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1493.14ART DESIGN 442 3.14.1 Art Design Paper 1 442 1 For More Free KCSE Past papers Visit www.freekcsepastpapers.com150For More Free KCSE Past papers Visit www.freekcsepastpapers.com151For More Free KCSE Past papers Visit www.freekcsepastpapers.com152For More Free KCSE Past papers Visit www.freekcsepastpapers.com153For More Free KCSE Past papers Visit www.freekcsepastpapers.com1543.14.2 Art Design Paper 2 Practical 442 2 For More Free KCSE Past papers Visit www.freekcsepastpapers.com155For More Free KCSE Past papers Visit www.freekcsepastpapers.com.


Marks Kenya Certificate of Secondary Education, 2019919417 223es19417 6Given that R and T are related by the equation Log R Log K n Log T, determine thevalue of; oan 1 mark K 2 marks Kenya Cerificate of Secondary Edueation, 20192323Question 2 You are provided with the following: Ametre rule Asstand, boss and clamp Apiece of sting A20g mass A50g mass A measuring cylinder containing water Aconcave mirtor Ascreen Acandle Pieces of sewing threadsg Amimor holder Lens holder Proceed as follows:PART A Using string, suspend the metre rule on the stand so that it balances horizontally a itscenter of gravity. Record the centimetre mark at which the metre rule balances. Centimetre mark senso CRY 0 mark With the metre rule balanced at its centre of gravity, suspend a 20g mass ata distance of30em from the centre of gravity. Suspend the 50g mass on the other side ofthe centre oferavity and adjust its position until the rue is balanced, See figure 3. 2 String ITT TTT T metre rate208 50g, Figure 3 Kenya Certificate of Secondary Education, 2019919417 2323 Turn overRecord the distance d of the 50g mass from the centre of gravity.em Record the volume of the water in the measuring cylinder provided. VE omen 0 mark 0 mark Gi Immerse the 20g mass fully into the water and adjust the positon of the 50g mass so that the rule balances horizontally,Record the volume V, of the water plus 20g mass and the distance d, of the 50 mass from the centre of gravity. Mark 1 mark 1 mark G marks gGil Determine the volume of the water displaced U1 Determine the weight of the water displaced. Density of water I gem i . .


2 String ITT TTT T metre rate208 50g, Figure 3 Kenya Certificate of Secondary Education, 2019919417 2323 Turn overRecord the distance d of the 50g mass from the centre of gravity.em Record the volume of the water in the measuring cylinder provided. VE omen 0 mark 0 mark Gi Immerse the 20g mass fully into the water and adjust the positon of the 50g mass so that the rule balances horizontally,Record the volume V, of the water plus 20g mass and the distance d, of the 50 mass from the centre of gravity. Mark 1 mark 1 mark G marks gGil Determine the volume of the water displaced U1 Determine the weight of the water displaced. Density of water I gem i ..a Use the principle of moments to determine the apparent weight ofthe 20g mass hen fully immersed in water. G 10.Nkg" Calculate the weight of the 20g mass in air g 10 Nig! Kenya Certificate of Secondary Education, 201919417 2323 2 marks 1 mark g9 Determine the apparent loss in weight of the 20 mass. 1 mark PARTB Light the candle and place it at distance u 20cm in front ofthe concave mirror. Adjust the position ofthe screen until a sharp image of the candle flame is obtained. See figure 4.Figure 4 Read and record the distance v between the sereen and the mirror. Q mark i Determine:1 emineionnottieminrgtentucn 2, iy Mev gen f my Kenya Certificate of Secondary Education, 20192323919417 Turn over Repeat part e for distance u, Read and record the distance v, between the screen and the mirror. 1 mark ii Determine the magnification m, ofthe mirror. 1 mark iii Hence determine f, Determine the average value off. Mark THIS IS THE LAST PRINTED PAGE.Kenya Cerificate of Secondary Education, 2019919417 2323.


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THE KENYA NATIONAL EXAMINATIONS COUNCILKenya Certificate of Secondary Education101 3 ENGLISH Paper 3 Creative Composition and Essays Based on Set Texts Nov. 2019 - 2 hours Candidate's Signature ... Instructions to candidates 2 . Write your name and index number in the spaces provided above. Sign and write the date of examination in the spaces provided above. C Answer three questions only. A Questions one and two are compulsory. 0 In question three choose only one of the optional texts you have prepared on. 9 Where a candidate presents work on more than one optional text, only the first one toappear will bo marked. G Each of your essays must not exceed 450 words. H All answers should be written in the answer booklet provided. I This paper consists of 16 printed pages. Candidates should check the question paper to ascertain that all the pages are printed asindicated and that no questions are missing. K Candidates must answer the questions in English. For Examiner's Use Onlycvewion Me Soaros 3 20Twulssoe 2019 The Kenya National Examinations Council1013919249 Turn overAnswer three questions only.1. Imaginative Composition Compulsory 20 marks Either Write a story beginning with the following sentence: Lwas mistaken to have thought that the night would be like other peaceful nightsOr Write a composition on the advantages and disadvantages of the internet.2. The Compulsory Set Text 20 marks HR, Ole Kulet, Blossoms of the SavannahIrresponsible decisions can lead to serious consequences, Referring closely to H.R. Ole Kulet inBlossoms of the Savannah, write an essay in support of this statement.3. The Optional Set Texts 20 marks Answer any one of the following three questions. Either TheShort StoryMoran Ed. ,. Memories We Lost and Other StoriesWrite a composition on the evils of war, using illustrations from The President byMariatu Kamara,Or DramaDavid Mulwa, InheritanceUL-gotten wealth can never bring true happiness.


The Compulsory Set Text 20 marks HR, Ole Kulet, Blossoms of the SavannahIrresponsible decisions can lead to serious consequences, Referring closely to H.R.Ole Kulet inBlossoms of the Savannah, write an essay in support of this statement.3. The Optional Set Texts 20 marks Answer any one of the following three questions. Either TheShort StoryMoran Ed. ,. Memories We Lost and Other StoriesWrite a composition on the evils of war, using illustrations from The President byMariatu Kamara,Or DramaDavid Mulwa, InheritanceUL-gotten wealth can never bring true happiness. Write a composition in support ofthisstatement, drawing examples from Lucuna Kasoo s life. Or TheNovelJohn Steinbeck, The PeartDesire without limits can be a source of agony both to ourselves and our family members. Using illustrations from The Pearl, write an essay in support of this statement. Kenya Cerificate of Secondary Education, 2019919249 1003.


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Www.freekcsepastpapers.comPage 1 CEKENAS MOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 1 CHEMISTRY Paper 1 Theory TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1.All working must be clearly shown where necessary.2.Mathematical tables and silent electronic calculations may be used1.Give two difference between a thistle funnel and a dropping funnel 2marks 2.Give names of the following processes used toa Separate calcium carbonate from water 1mark b Separate a mixture of nitrogen and Helium 1mark 3.The table below shows some solutions and their pH valueSolution pH values P 1.5 Q 6.0 R 14.0 S 8.0 Which of the above solutions is likely to be of a Sodium carbonate 1mark b Solution with high concentration of Hydrogen ions 1mark 4.In the laboratory preparation of oxygen gas, Hydrogen peroxide is used.a Name the catalyst used 1mark b Write a balanced chemical equation for the reaction 1mark 5.State three observation made when a piece of potassium metal is dropped into cold water giving a reason for each. 3marks 6.In the extraction of iron, the iron ore is reduced to iron in a blast furnacea Name the main ore used in extraction of iron 1mark b What is the main reducing agent in the blast furnace 1mark c Write the equation for the reaction through which the iron ore is reduced to iron in the blast furnace. 1mark 7.Draw the structure of the followinga Mg 1mark b Hydroxonium ion 1mark 8.When 27.8g of hydrated aluminium oxide OXHOAl was heated to a constant mass 20.6 g of aluminiumoxide was obtained. Determine the value of X Al 27, O 16, H 1 3marks 9.In the Haber process, the industrial manufacture of ammonia is given by the following equation gggNHHN2 molkJH 97 a Name one source of nitrogen gas used in this process 1mark b Name the catalyst used in the above reaction 1mark c What is the effect of increasing temperature on the yield of ammonia?


Www.freekcsepastpapers.comPage 1 CEKENAS MOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 1 CHEMISTRY Paper 1 Theory TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1.All working must be clearly shown where necessary.2.Mathematical tables and silent electronic calculations may be used1.Give two difference between a thistle funnel and a dropping funnel 2marks 2.Give names of the following processes used toa Separate calcium carbonate from water 1mark b Separate a mixture of nitrogen and Helium 1mark 3.The table below shows some solutions and their pH valueSolution pH values P 1.5 Q 6.0 R 14.0 S 8.0 Which of the above solutions is likely to be of a Sodium carbonate 1mark b Solution with high concentration of Hydrogen ions 1mark 4.In the laboratory preparation of oxygen gas, Hydrogen peroxide is used.a Name the catalyst used 1mark b Write a balanced chemical equation for the reaction 1mark 5.State three observation made when a piece of potassium metal is dropped into cold water giving a reason for each. 3marks 6.In the extraction of iron, the iron ore is reduced to iron in a blast furnacea Name the main ore used in extraction of iron 1mark b What is the main reducing agent in the blast furnace 1mark c Write the equation for the reaction through which the iron ore is reduced to iron in the blast furnace. 1mark 7.Draw the structure of the followinga Mg 1mark b Hydroxonium ion 1mark 8.When 27.8g of hydrated aluminium oxide OXHOAl was heated to a constant mass 20.6 g of aluminiumoxide was obtained. Determine the value of X Al 27, O 16, H 1 3marks 9.In the Haber process, the industrial manufacture of ammonia is given by the following equation gggNHHN2 molkJH 97 a Name one source of nitrogen gas used in this process 1mark b Name the catalyst used in the above reaction 1mark c What is the effect of increasing temperature on the yield of ammonia? Explain 2marks 10.


1mark 7.Draw the structure of the followinga Mg 1mark b Hydroxonium ion 1mark 8.When 27.8g of hydrated aluminium oxide OXHOAl was heated to a constant mass 20.6 g of aluminiumoxide was obtained. Determine the value of X Al 27, O 16, H 1 3marks 9.In the Haber process, the industrial manufacture of ammonia is given by the following equation gggNHHN2 molkJH 97 a Name one source of nitrogen gas used in this process 1mark b Name the catalyst used in the above reaction 1mark c What is the effect of increasing temperature on the yield of ammonia? Explain 2marks 10. Describe the correct process of heating a liquid in a test-tube using a bunsen burner. 3marks 11. Draw a labelled diagram of a set up that can be used to prepare dry sample of carbon IV oxide using calciumcarbonate 3marks 12. A Draw structural formulae of two positional isomers with molecular formula C4H8 2marks b Study the equation below and answer the questions that followHClClHCClHC 146i State the condition under which this reaction occurs 1mark www.freekcsepastpapers.comPage 2 ii Give the general name of this type of reaction 1mark 13. A Define hydration energy 1mark b Given that the lattice energy of NaCl is 781kJ mol and hydrated energy of Na and Cl are -390kJ mol and 384kJ mol respectively. Calculate the heat of solution of one mole of NaCl s using energy cycle. 3marks 14. 240cm3 of nitrogen I oxide gas takes 16 seconds to diffuse through a certain porous pot. 300cm3 of x takes 12 seconds to diffuse through the same pot calculate the relative molecular mass of gas x. N 14, O 16 3marks 15. Draw a well labelled diagram that can be used during electrolysis of molten sodium chloride in the laboratory 3marks 16.


300cm3 of x takes 12 seconds to diffuse through the same pot calculate the relative molecular mass of gas x. N 14, O 16 3marks 15. Draw a well labelled diagram that can be used during electrolysis of molten sodium chloride in the laboratory 3marks 16. The figure below describes the manufacture of detergent B a What type of detergent is B 1mark b Draw the structure of detergent B 1marks c State two disadvantage of using detergent B 2marks 17. Use the flow chart below to answer the question below a Explain the observation in step II 1mark b Name the process that takes place when flower petals are put into solution T 1mark c Reaction in step I takes place only in presence of moisture. Give a reason for this 1mark 18. The diagram below represent a dry cell with Zinc can and graphite as the electrodes and ammonium chloride paste as an electrolyte a Write an ionic equation for the reaction taking place at i Anode 1mark ii Cathode 1mark b State the property of carbon powder that make it suitable for use in the cell 1mark c State one other substance that could be used in place of manganese IV oxide 1mark 19. The diagram bellow represents part of periodic table. Use it to answer the question that follow. A Q Z W X a Write the electronic arrangement for the stable ion formed by X 1mark b Write an equation for the reaction between W and Q 1mark c Compare the ionization energy of element A and Z. Explain. 2marks Zinc can Ammonium chloride Carbon manganese iv oxidewww.freekcsepastpapers.comPage 3 20. Write equations to show the effect of heat on each of the following a Ammonium nitrate 1mark b Potassium nitrate 1mark c Anhydrous iron II sulphate 1mark 21.


Explain. 2marks Zinc can Ammonium chloride Carbon manganese iv oxidewww.freekcsepastpapers.comPage 3 20. Write equations to show the effect of heat on each of the following a Ammonium nitrate 1mark b Potassium nitrate 1mark c Anhydrous iron II sulphate 1mark 21. When excess chlorine gas is bubbled through diluted sodium hydroxide solution; the resulting solution act as a bleaching agent a Write an equation for the reaction between chlorine gas and sodium hydroxide solution 1mark b Name the bleaching agent 1mark c Write an equation to show the bleaching and explain how it occurs 2marks 22 Alpha and beta particles can be distinguished using papers, aluminium foil and an electric field complete the diagram below to show how this is done 3marks 23. During electrolysis of magnesium sulphate, a current of 0.3A was passed for 30 minutes calculate the volume of gas produced at the anode molar gas volume 24dm3, IF 96500C 3marks 24. Starting with sodium metal, describe how a sample of crystal of sodium hydrogen carbonate may be prepared 3marks 25. When 20cm3 of 0.5M sulphuric VI acid was mixed with 20cm3 of 1M NaOH, the temperature of the solution rose from 24.0oC to 32.0oC calculate the molar heat of neutralisation. Specific heat capacity of the solution is 4.2Jg-1density is 1g cm3 3marks 26.


Starting with sodium metal, describe how a sample of crystal of sodium hydrogen carbonate may be prepared 3marks 25. When 20cm3 of 0.5M sulphuric VI acid was mixed with 20cm3 of 1M NaOH, the temperature of the solution rose from 24.0oC to 32.0oC calculate the molar heat of neutralisation. Specific heat capacity of the solution is 4.2Jg-1density is 1g cm3 3marks 26. The table below shows the test carried out on a sample of water and results obtained Sample Test Observation A Addition of NaOH solution drop wise until in excess White precipitate soluble in exess B Adding of NH3 aq solution White precipitate C Addition of dilute HNO3 followed by Ba NO3 2 White precipitate a Identify the anion present in the water 1mark b Write the ionic equation for the reaction in C 1mark c Write the formula of the complex ion in A 1mark www.freekcsepastpapers.comPage 4 CEKENAS MOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 2 Chemistry PAPER 2 Theory TIME: 2 HOURS 1. The grid below represents part of the periodic table. Study it and answer the questions that follow. The letters do not represent the actual symbol of elements. G I V K J L M a i Select elements which belong to the same chemical family 1mark ii Write the formulae of ions for two elements in the same period 1mark b The first ionization energies of two elements K and M at random are 577kJ mol and 494kJ mol. I Write equations for the 1st ionisation energies for elements K and M and indicate their energies 2marks ii Explain the answer in b i 1mark iii Write the formula of the compound formed when I and L react 1mark iv Give one use of element L 1mark c I How do the reactivity of elements K and L compare? Explain 2marks II Element L and M form chlorides.


G I V K J L M a i Select elements which belong to the same chemical family 1mark ii Write the formulae of ions for two elements in the same period 1mark b The first ionization energies of two elements K and M at random are 577kJ mol and 494kJ mol. I Write equations for the 1st ionisation energies for elements K and M and indicate their energies 2marks ii Explain the answer in b i 1mark iii Write the formula of the compound formed when I and L react 1mark iv Give one use of element L 1mark c I How do the reactivity of elements K and L compare? Explain 2marks II Element L and M form chlorides. Complete the table by writing the formulae of each chloride and state the nature of the solutions 2marks Element Formula of chloride Nature of chloride solution L M III The chloride of element M vaporizes easily while its oxide has a high melting point. Explain 2marks IV Which elements forms a trivalent: a Cation mark b Anion mark 2. I The following is a structure of an organic compound. A Which organic series does the compound belong? 1mark b Give the structures and names of the reactants that form the above compound 2marks ii The table shows structural formula of some organic compounds Compound Structural formula A CH3CH2CH2CH3 B CH3CH2COOH C CH3CHCH2 D CHCCH3 E CH3CH2CH2CH2OH a Give the chemical test that can be used to identify compound C. 1mark b Compare the boiling points of compound E and A 2marks c State and explain the observation made when Sodium carbonate is added to compound G. 2marks d Write an equation to show the reaction between compound E and magnesium metal and give the name of the product formed. 2marks e The following is a structure of a section of a polymerwww.freekcsepastpapers.comPage 5 i Draw the structure of the monomer 1mark ii Give the name of the polymer 1mark iii State one use of the polymer. 1mark 3.


2marks d Write an equation to show the reaction between compound E and magnesium metal and give the name of the product formed. 2marks e The following is a structure of a section of a polymerwww.freekcsepastpapers.comPage 5 i Draw the structure of the monomer 1mark ii Give the name of the polymer 1mark iii State one use of the polymer. 1mark 3. A Dry chlorine gas was passed over heated iron resulting in P. P was dissolved in water resulting in the formation of a solution of P. To a little of the solution P a few drops of Sodium hydroxide were added and solid Q was obtained. I Name substance P and Q 2marks II Write equations to show how substances P and Q were formed. 2marks III Name a suitable drying agent for chlorine gas 1mark b Chlorine burns in dry ammonia gas as shown in the diagram below. I Identify solid N 1mark ii A colourless and odourless gas is produced. Identify the gas 1mark iii Write the equation for the burning of chlorine in dry ammonia gas 1mark iv 3g of divalent metal X atomic mass 24 react with dilute hydrochloric acid. Calculate the volume of hydrogen gas produced at STP. X 12, H 1 molar gas volume at STP 22.4dm3 3marks v When excess chlorine was bubbled into hot concentrated sodium hydroxide, the following reaction occurred. LaqaqaqgOHNaClNaClONaOHCl3 . In which product did chlorine under oxidation. Explain 2marks 4. A Aqueous potassium sulphate was electrolysed using platinum electrodes in a cell. I Shows the product formed at the anode and cathode with the help of an equation 2marks Anode Cathode ii Why would it not be advisable to electrolyse aqueous potassium sulphate using potassium metal electrodes?


Explain 2marks 4. A Aqueous potassium sulphate was electrolysed using platinum electrodes in a cell. I Shows the product formed at the anode and cathode with the help of an equation 2marks Anode Cathode ii Why would it not be advisable to electrolyse aqueous potassium sulphate using potassium metal electrodes? 1mark b Use the standard electrode potential for elements A, B, C, D and F given below to answer that follow; E0 volts 87.2.0200.038.2290.222 aqgaqaqaqaqaqaqsaqFeFDeDCeCBeBAeA I Which element is likely to be hydrogen? Explain 1mark II What is the Eo value of the strongest reducing agent? 1mark III In the space provided draw a labelled diagram of the electrochemical cell that would be formed when the half cells of elements B and D are combined. 3marks IV Calculate the Eo value of the electrochemical cell constructed in III above 1mark c During electrolysis of aqueous copper ii sulphate using copper electrodes, a current of 0.2 amperes was passed through the cell for 5 hours. I Write an ionic equation for the reaction that took place at the anode 1mark ii Determine the change in mass of the anode which occurred as a result of electrolysis CFaradayICu96500,5.63 1mark Chlorine gas Dry ammonia White fumes of solid Nwww.freekcsepastpapers.comPage 6 5. A The diagram below represents the electrolytic cell used for extraction of aluminium. I Write the formula of the main ore in which aluminium is extracted 1mark ii Explain why the ore is first dissolved in hot concentrated sodium hydroxide.


I Write an ionic equation for the reaction that took place at the anode 1mark ii Determine the change in mass of the anode which occurred as a result of electrolysis CFaradayICu96500,5.63 1mark Chlorine gas Dry ammonia White fumes of solid Nwww.freekcsepastpapers.comPage 6 5. A The diagram below represents the electrolytic cell used for extraction of aluminium. I Write the formula of the main ore in which aluminium is extracted 1mark ii Explain why the ore is first dissolved in hot concentrated sodium hydroxide. 2maks iii Write equations for the reactions that takes place at I The anode 1mark II The cathode 1mark iv State why the graphite lining is used as the cathode 1mark v Give two reasons for mixing aluminium oxide with cryolite in the electrolyte cell 2marks b Aluminium is resistant to corrosion while iron corrodes very fast. I Why is aluminium not used to make window frames? 1mark II State one reason why galvanised iron is resistant to corrosion even when the protective surface of zinc is broken? 1mark III Write an equation to show the reaction between aluminium and concentrated sodium hydroxide solution 1mark IV Explain how one word obtain aluminium oxide given the following; aluminium chloride solid, sodium hydroxide solid and distilled water. 3marks 6. A What are isotopes 1mark b The table below shows the isotopic composition of naturally occurring neon particle Ne2210 Abundance 9.2 0.3 90.5 i Which is the most stable isotope of Neon? Explain 2marks ii Calculate the relative mass of Neon 2marks iii Balance the nuclear equation below NC6 1mark iv Distinguish between nuclear fission and nuclear fusion. 1mark c Bismuth undergoes radioactive decay. The table below shows the mass of Bismuth remaining at different times.


Explain 2marks ii Calculate the relative mass of Neon 2marks iii Balance the nuclear equation below NC6 1mark iv Distinguish between nuclear fission and nuclear fusion. 1mark c Bismuth undergoes radioactive decay. The table below shows the mass of Bismuth remaining at different times. Time min 0 6 12 22 38 62 100 mass of Bismuth remaining g 50 41.5 32.5 23 14.5 6 1.5 i Plot a graph of mass of bismuth remaining vertical axis against time. 3marks ii From the graph determine I Mass of Bismuth remaining after 30 minutes 1mark II The half-life of bismuth. 1mark III What would happen to the rate of disintegration of bismuth if the temperature is increased? Explain 2marks d State one application of radio isotopes in agriculture 1mark www.freekcsepastpapers.comPage 7 CEKENAS MOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY Paper 3 CONFIDENTIAL REQUIREMENTS 1. Solid E 2. 50cm3of solution F 3. 80cm3of solution H 4. 0.5g of solid K 5. 0.5g of solid L 6. Distilled water 7. Burette 8. Pipette 9. Pipette filter 10. Label 11. 250ml volumetric flask 12. Two 250ml conical flasks 13. Test tube holder 14. 2 boiling tube 15. 6 test tubes 16. Stopwatch 17. 10ml measuring cylinder 18. Spatula 19. 0.5g sodium hydrogen carbonate 20. 5cm3of ethanol 21. Filter paper 3 pieces 22. Filter funnel 23. Blue and red litmus paper Access to 1. 0.1M BaCl2 2. 2M HCl 3. 2M Ammonia solution 4. 2M NaOH 5. 2M H2SO4 acid 6. Source of heat 7. Phenolphthalein indicator Preparations 1.


2M H2SO4 acid 6. Source of heat 7. Phenolphthalein indicator Preparations 1. Solid E 5cm magnesium ribbon 2. Solution F 2M HCl 3. Solution H 0.375M NaOH 4. Solid K sodium benzoate 5. Solid L Ammonium aluminium sulphatewww.freekcsepastpapers.comPage 8 CEKENAS MOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 3 Chemistry PRACTICAL Paper 3 TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1. Answer all the questions in the spaces provided 2. All working must be clearly shown where necessary. 3. You are not allowed to start working with the apparatus for the first 15 minutes. This time is to enable you read the question paper and make sure you have all the requirements. 1. You are provided with: - Magnesium ribbon solid E - 2M hydrochloric acid, solution F - 0.375M sodium hydroxide, solution H You are required to determine i The rate of reaction between magnesium and hydrochloric acid ii The mass of 1cm length of magnesium ribbon PROCEDURE 1 Step 1: Cut out five pieces of exactly 1cm length of magnesium ribbon solid E. Carefully fill the burette with solution F. Step 2: Drain from the burette 10cm3 solution F into a test tube. Put one piece of magnesium ribbon into the tube and immediately start a stopwatch. Record the time taken for the magnesium ribbon to completely react. Step 3: Transfer all the contents of the test tube into a 250ml volumetric flask. Rinse the test tube with distilled water and put in into the volumetric flask. Step 4: Repeat step 2 and 3 by placing 9cm3 of solution F and 1cm3 of distilled water shake the contents before use. After each experiment transfer the mixture into the volumetric flask. Repeat the procedure using contents in test tube 3, 4 and 5 as shown in the table below.


Step 4: Repeat step 2 and 3 by placing 9cm3 of solution F and 1cm3 of distilled water shake the contents before use. After each experiment transfer the mixture into the volumetric flask. Repeat the procedure using contents in test tube 3, 4 and 5 as shown in the table below. RETAIN THE SOLUTION IN THE VOLUMETRIC FLASK FOR USE IN PROCEDURE II Table I Test tube number 1 2 3 4 5 Volume of solution F cm3 10 9 8 7 6 Volume of water added cm3 0 1 2 3 4 Time taken seconds t1 sec-1 5mks a i Plot a graph of rate t1 , against volume of solution F. 3mks ii Use the graph to determine the time taken for 1cm length of magnesium to dissolve if volume of water added is 1.5cm3 . 2mks iii a In terms of rate of reaction, explain the shape of the graph 2mks PROCEDURE II Add distilled water into the solution in the 250ml volumetric flask up to the mark. Label it as solution G. Clean the burette and fill it with Sodium hydroxide, solution H. Pipette 25cm3 of solution G into 250ml conical flask. Add 2 drop of phenolphthalein indicator and titrate it with solution H from the burette. Record your results in table below Table II 4mks I II III Final burette reading cm3 Initial burette reading cm3 Volume of solution H used cm3 www.freekcsepastpapers.comPage 9 b Determine the i Average volume of solution H used. 1mk ii Number of moles of hydrochloric acid in 250cm3 of solution G. 2mks iii Number of moles of hydrochloric acid solution F that reacted with solid E. 2mks iv The mass of magnesium ribbon that reacted. Mg 24 . 2mks v Mass of 1cm length magnesium ribbon. 1mk 2. You are provided with solid K.


On adding 3cm3of 2M sodium hydroxide to a simple of solution B, a white precipitate C is formed that dissolves to form a colourless solution D on adding more sodium hydroxide. On adding 2M aqueous ammonia, a white precipitate E is formed which dissolves in excess aqueous ammonia. On adding 5cm3 of 1M lead II nitrate to a sample of solution B a white precipitate G is formed which remains on heating. Identify: 3marks a Gas A b Solution B c Precipitate C d Solution D e Precipitate E f Precipitate G 4. Potassium sulphite solution was prepared and divided into two portions. The first portion gave a white precipitate when reacted with lead II nitrate. On addition of dilute nitric V acid the white precipitate disappeared. A Give the identity of the compound which formed as the white precipitate. 1mark b Write the equation for the reaction between dilute nitric V acid and the compound whose formula is written in a above. 1mark c What observation would be made if one drop of potassium dichromate solution was added to the second portion followed by dilute sulphuric VI acid? 1mark 5. A What name is given to the process by which an alkanol is formed from a carbohydrate? 1 mark b Explain why the solubility of ethane in water is lower than that of ethanol. 1 mark 6. Study the standard reduction potential given and answer the questions that follow. The letters are not the actual symbols of the elements . E volts M2 aq 2e M s -0.76 N2 aq 2e N s -2.37 P aq e P s 0.80 Q2 aq 2e Q s : -0.14 a The standard reduction potential for Fe 2 aq is -0.44 volts. Explain why M would be more effective in protecting iron from rusting than P. 2 marks b Calculate the E value for the cell represented as M s M2 aq P aq P s . 1 mark 7.


Explain why M would be more effective in protecting iron from rusting than P. 2 marks b Calculate the E value for the cell represented as M s M2 aq P aq P s . 1 mark 7. A State Charles s law. 1mark b A sealed glass tube containing air at s.t.p was immersed in water at 1000c. Assuming that there was no increase in the volume of the glass tube due to the expansion of the glass, calculate the pressure of the inside tube. Standard pressure 760mmHg, standard temperature 273K 2marks 8. A Methane reacts with oxygen as shown by the equations I and II below: I CH4 g 2O2 g CO2 g 2H2O l II 2CH4 g 302 g 2CO g 4H2O l Which one of the two reactions represents the complete combustion of methane? Explain. 1 marks b 80cm3 of methane was reacted with 150cm3 of oxygen forming carbon IV oxide and water. If the resultant mixture was allowed to cool to room temperature: Calculate the volume of: i Carbon IV oxide formed 1 mark ii The unreacted gaseous mixture. Mark www.freekcsepastpapers.comPage 20 9. An isotope of Uranium; 23492 decays by emission of an alpha particle to form thorium Th a Write the equation for the nuclear reaction undergone by the isotope. 1 mark b Explain why it is not safe to store radioactive substances in containers made from aluminum sheets. 1 mark c Give one use of radioactive isotopes in agriculture 1mark 10. Consider the following reaction at equilibrium. PCl5 g PCl3 g Cl2 g Complete the table below to show the effect of different factors on the position of equilibrium. Factor Effect on the equilibrium position i Decrease pressure ii Removing chlorine iii Adding Helium gas to mixture 3marks 11. Sulphur burns in air to form sulphur IV oxide. A simple energy level diagram for the reaction is given below.


Describe you would prepare a pure sample of zinc carbonate starting with zinc oxide. 3marks 16. A The diagram below shows a structure of water molecules. Name the bonds labeled R - mark S - mark b Using dot and cross x diagram show bonding in; i Potassium chloride K 19 Cl 17 1mark ii Carbon tetrachloride C 6, Cl 17 1mark www.freekcsepastpapers.comPage 21 17. I In an experiment to determine solubility of solid P in water at 250C, the following results were obtained. Mass of empty evaporating dish 24.2g Mass of evaporating dish saturated solution 40.4g Mass of evaporating dish dry solid P 28.4g Using the information above calculate the solubility of solid P at 250C in g 100g of water. 2marks ii State one precaution observed when carrying out the experiment in i above 1 1mark 18. I On complete combustion of a hydrocarbon 0.88g of carbon iv oxide and 0.36g of water were formed calculate the molecular formula of the hydrocarbon given that relative molecular mass of the hydrocarbon is 70. C 12, H 1, O 16 2marks ii Draw the structural formula of the hydrocarbon in i above and give its name 1mark 19. The table below shows solutions and their PH values. Solution PH value L 2.0 M 7.0 N 14.0 i Select two solutions that will react with calcium metal. Give a reason. 2marks ii Which solution is likely to be that of sodium chloride solution? 1mark 20. During the extraction of aluminium, cryolite is added to molten aluminium oxide. I State the function of cryolite during the process 1mark ii Give two reasons why aluminium is used in making overhead cables. 2marks 21. The diagram below represents a paper chromatogram of pure inks marked 1, 2, 3 and 4. Ink 5 is a mixture that contains inks 1 and 4 only.


2marks 21. The diagram below represents a paper chromatogram of pure inks marked 1, 2, 3 and 4. Ink 5 is a mixture that contains inks 1 and 4 only. A Give a reason why ink 1 moves faster to the solvent front than ink 2. 1mark b Show on the chromatogram diagram the: i chromatography of ink 5. 1mark ii The baseline 1mark 22. A What is the half life? 1mark b X g of a radioactive element was reduced to 12.5g in 15.6years. If the half life of the element is 5.2years. Calculate the value of X. 2marks 23. Study the table below and answer the question that follow. The letters do not represent the actual symbols of the element. Formula of ion Electron configuration W2 2 V2- 2.8 X3 2.8 U2 2.8 Y- 2.8.8 a Select letters representing elements found in; i The same group and name the group 1mark Letters Group .. ii Period three and name the period. 1mark Letters ..Period . B What is the family name given the group members to which element Y belongs 1mark 24. Both anhydrous calcium chloride and anhydrous copper II sulphate are put in separate petri dishes in the laboratory and left overnight. A What was the observable difference made in the morning? 2marks www.freekcsepastpapers.comPage 22 b Name the process represented by each change. 1mark Anhydrous calcium chloride: Anhydrous copper II sulphate: 25. Plastics are made from petroleum products. A Name two plastics derived from ethene and give their use. 2marks b State one disadvantage of continuous use of plastics 1mark 26.


Plastics are made from petroleum products. A Name two plastics derived from ethene and give their use. 2marks b State one disadvantage of continuous use of plastics 1mark 26. Dilute hydrochloric acid and Sodium sulphite were reacted as shown in the set-up below: a Name the gas produced in the flask 1mark b Write a chemical equation for the reaction taking place 1mark c Give two reasons why no gas was collected in the gas jar. 1mark 27. Temporary water hardness can be removed by boiling; a What is hard water? 1mark b Write a chemical equation to show how temporary hardness can be removed by boiling. 1mark c State one advantage of hard water. 1mark 28. Study the set-up below and answer the questions that follow; a Name gas X . 1mark b State the condition which is not indicated on the diagram for gas X to be formed. 1mark 29. Calculate the number of moles of ammonia in 8.9dm3 of the gas at s.t.p Molar gas volume at s.t.p 22.4dm3, L 6.0 x 1023 mol-1 1mark Gas X Chlorine water Gas jar Sodium sulphite Dilute HCl aq www.freekcsepastpapers.comPage 23 EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 2 CHEMISTRY PAPER 2 TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1. Answer all the questions 2. KNEC or electronic calculators may be used in calculations. 3. All working MUST be shown clearly where necessary. 1. The table below shows some elements in the periodic table. Use it to answer the questions that follow. The letters are not the actual symbols of the elements. F A G E B D C i Select the most reactive metal. Explain. 1mk ii Write the formula of the compound formed between element G and D. 1mk iii Compare the following with explanations: I The electric conductivity of A and E. 2mks II The atomic radius of B and D.


1mk ii Write the formula of the compound formed between element G and D. 1mk iii Compare the following with explanations: I The electric conductivity of A and E. 2mks II The atomic radius of B and D. 2mks iv Which element has the highest ionisation energy? Explain. 2mks v Show on the periodic table above an element Z belonging to period 4 and group VI. 1mk vi Element C has relative atomic mass of 40.2 and has two isotopes of mass 39 and 42. Calculate the relative abundance of each isotope. 3mks 2. The scheme below shows a series of reactions starting with propan-I-ol. Study it answer the questions that follow. A Name the type of reaction that takes place in: i Step I 1mk ii Step II 1mk b Write the equation for the reaction that takes place in step III. 1mk c Name the substances labelled: A, C, D and E. 2 mks d Draw the structural formula of the product C. 1mk e Name the process in step IV 1mk f Name compound B and state the type of reaction involved in its formation. 2mks g If the relative molecular mass of B is 35700, determine the value of n. 2mks www.freekcsepastpapers.comPage 24 h Below are structures of two cleaning agents X and Y. X: R COO - Na i Identify the cleaning agent suitable to be used with water containing magnesium chloride. 1mk ii State one advantage of using cleaning agent Y. 1mk 3. Study the reaction scheme shown below and answer the questions that follow. A Identify the following: i Metal S 1mk ii Green precipitate T: 1mk iii Blue precipitate U: 1mk b Write ionic equation for the reaction that takes place in step II. 1mk c i Distinguish between a strong acid and a weak acid.


Study the reaction scheme shown below and answer the questions that follow. A Identify the following: i Metal S 1mk ii Green precipitate T: 1mk iii Blue precipitate U: 1mk b Write ionic equation for the reaction that takes place in step II. 1mk c i Distinguish between a strong acid and a weak acid. 1mk ii A student tested pH value of solutions using universal indicator and obtained the following results: Solution A B C D E Colour Blue Violet Red Green Yellow PH 10 14 1 7 5 Classification Neutral Complete the table by classifying the solutions as strongly acid, weakly acid, strongly basic, weakly basic. 2mks iii Identify two solutions likely to react with aluminium oxide. Give a reason. 2mks 4. A Use the diagram below and answer the questions that follow: The above experiment was performed using a carbon electrode and another electrode. I Identify electrode B. 1mk ii Name the colourless gas Y. 1mk iii Explain why no gas was observed in X. 1mk iv Write chemical equation for the reaction which occur at electrode: A: 1mk B: 1mk b Study the reduction potentials below and answer the questions that follow. Half cell E Volts A2 aq 2e- A s 0.34 B aq e- B s -2.92 12 C2 g e- C- aq 2.87 i Identify the weakest oxidizing agent. 1mk ii Calculate the e.m.f of the cell that would produce highest output voltage. 2mkswww.freekcsepastpapers.comPage 25 iii Write the cell representation for the cell formed in ii above. 1mk c In electrolysis of dilute magnesium sulphate using inert electrodes, a current of 2.5A was passed through the electrolyte for 1 hour 20 minutes. Calculate the volume of the gas produced at the anode at standard temperature and pressure s.t.p. IF 96500C, molar volume at s.t.p 22.4 dm3 3mks 5.


1mk c In electrolysis of dilute magnesium sulphate using inert electrodes, a current of 2.5A was passed through the electrolyte for 1 hour 20 minutes. Calculate the volume of the gas produced at the anode at standard temperature and pressure s.t.p. IF 96500C, molar volume at s.t.p 22.4 dm3 3mks 5. A Define standard enthalpy of combustion of a substance. 1mk b Study the heats of combustion shown below: H2 g O2 g H2O l H -393KJmol-1 C s O2 g CO2 g H -286KJmol-1 C3H8 5O2 g 3CO2 g 4H2O l H -2218KJmol-1 i Draw an energy level diagram linking heat of formation of propane C3H8 with its heat of combustion of its constituent elements. 2mks ii Use the information above to calculate heat of formation of propane. 2mks c A given mass of propane was used to heat one litre of water. The temperature of water rose from 25oC to 50.5oC Specific heat capacity of water 4.2Jg-1K-1 i Calculate the heat change for the reaction. 2mks ii Find the mass of propane burnt C 12; H 1 2mks d Calculate the calorific value of propane. 2mks e Apart from heating value, state two other factors to consider when choosing a fuel. 2mks 6. A The diagram below shows preparation of nitric V acid in the laboratory. I Name solid E. 1mk ii Give the reason why apparatus used is all made of glass. 1mk iii Write the equation for the reaction between solid E and concentrated sulphuric VI acid. 1mk iv State and explain two observations made during the experiment. 2mks b During the industrial manufacture of nitric V acid, a mixture of purified dry ammonia and air is passed through a catalyst at 900oC.


1mk iii Write the equation for the reaction between solid E and concentrated sulphuric VI acid. 1mk iv State and explain two observations made during the experiment. 2mks b During the industrial manufacture of nitric V acid, a mixture of purified dry ammonia and air is passed through a catalyst at 900oC. A series of reactions take place leading to production of concentrated nitric V acid. I Name the catalyst used. 1mk ii Give three reactions in order in which they occur leading to production of nitric V acid. 3mks iii Give one use of nitric V acid in agriculture. 1mk 7. A Name the main ore from which sodium metal is extracted. 1mk b The diagram below shows Down s cell for extraction of sodium. Study it and answer the questions that follow. Www.freekcsepastpapers.comPage 26 i Identify the following: I Gas Q 1mk II Electrode R 1mk III Liquid P 1mk ii Write equation for the reaction which takes place at the cathode. 1mk iii State the role of the following in the cell. I Calcium chloride 1mk II Steel diaphragm 1mk iv State one use of sodium metal. 1mk c i Give the name and formula of the major ore from which copper is extracted. 1mk ii Draw a diagram of a set up used in the electrolytic purification of blister copper.


I Calcium chloride 1mk II Steel diaphragm 1mk iv State one use of sodium metal. 1mk c i Give the name and formula of the major ore from which copper is extracted. 1mk ii Draw a diagram of a set up used in the electrolytic purification of blister copper. 2mks EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY PRACTICAL Paper 3 CONFIDENTIAL INSTRUCTIONS TO SCHOOLS In addition to the normal fittings and apparatus in the laboratory, each candidate would need the following: Solid P in a boiling tube 100 cm3 of solution Q 1 Burette 1 Pipette 1 Filter funnel 1 Label 1 Pipette filler 1 Thermometer 250 cm3 volumetric flask 1 Conical flask 1 Test tube holder Water bath 1g Solid E 4cm3 liquid G supplied in a test tube 1 Boiling tube 6 test tubes in a test tube rack Distilled water in a water bottle 2 Filter papers 10cm3 measuring cylinder 1 blue and 1 red litmus papers 1 wooden splint 1 Watch glass ACCESS TO Source of heat Phenolphthalein indicator supplied with a dropper 2M sodium hydroxide solution supplied with a dropper 2M ammonia solution supplied with a dropper Sodium chloride solution supplied with a dropper Barium nitrate solution supplied with a dropper Nitric v acid supplied with a dropper Acidified potassium manganate vii supplied with dropper Universal indicator supplied with a dropper pH chart PREPARATION Solution Q is 0.2M sodium hydroxide Solid P is 4.5 g oxalic acid supplied in a boiling tube Solid E is a mixture of 0.5g aluminium sulphate and 0.5 g zinc carbonate.


1mk c i Give the name and formula of the major ore from which copper is extracted. 1mk ii Draw a diagram of a set up used in the electrolytic purification of blister copper. 2mks EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY PRACTICAL Paper 3 CONFIDENTIAL INSTRUCTIONS TO SCHOOLS In addition to the normal fittings and apparatus in the laboratory, each candidate would need the following: Solid P in a boiling tube 100 cm3 of solution Q 1 Burette 1 Pipette 1 Filter funnel 1 Label 1 Pipette filler 1 Thermometer 250 cm3 volumetric flask 1 Conical flask 1 Test tube holder Water bath 1g Solid E 4cm3 liquid G supplied in a test tube 1 Boiling tube 6 test tubes in a test tube rack Distilled water in a water bottle 2 Filter papers 10cm3 measuring cylinder 1 blue and 1 red litmus papers 1 wooden splint 1 Watch glass ACCESS TO Source of heat Phenolphthalein indicator supplied with a dropper 2M sodium hydroxide solution supplied with a dropper 2M ammonia solution supplied with a dropper Sodium chloride solution supplied with a dropper Barium nitrate solution supplied with a dropper Nitric v acid supplied with a dropper Acidified potassium manganate vii supplied with dropper Universal indicator supplied with a dropper pH chart PREPARATION Solution Q is 0.2M sodium hydroxide Solid P is 4.5 g oxalic acid supplied in a boiling tube Solid E is a mixture of 0.5g aluminium sulphate and 0.5 g zinc carbonate. Liquid G is 4 cm3 of ethanol supplied in a stoppered test tubewww.freekcsepastpapers.comPage 27 EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY Paper 3 PRACTICAL TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES Answer all questions.


1mk ii Draw a diagram of a set up used in the electrolytic purification of blister copper. 2mks EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY PRACTICAL Paper 3 CONFIDENTIAL INSTRUCTIONS TO SCHOOLS In addition to the normal fittings and apparatus in the laboratory, each candidate would need the following: Solid P in a boiling tube 100 cm3 of solution Q 1 Burette 1 Pipette 1 Filter funnel 1 Label 1 Pipette filler 1 Thermometer 250 cm3 volumetric flask 1 Conical flask 1 Test tube holder Water bath 1g Solid E 4cm3 liquid G supplied in a test tube 1 Boiling tube 6 test tubes in a test tube rack Distilled water in a water bottle 2 Filter papers 10cm3 measuring cylinder 1 blue and 1 red litmus papers 1 wooden splint 1 Watch glass ACCESS TO Source of heat Phenolphthalein indicator supplied with a dropper 2M sodium hydroxide solution supplied with a dropper 2M ammonia solution supplied with a dropper Sodium chloride solution supplied with a dropper Barium nitrate solution supplied with a dropper Nitric v acid supplied with a dropper Acidified potassium manganate vii supplied with dropper Universal indicator supplied with a dropper pH chart PREPARATION Solution Q is 0.2M sodium hydroxide Solid P is 4.5 g oxalic acid supplied in a boiling tube Solid E is a mixture of 0.5g aluminium sulphate and 0.5 g zinc carbonate. Liquid G is 4 cm3 of ethanol supplied in a stoppered test tubewww.freekcsepastpapers.comPage 27 EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY Paper 3 PRACTICAL TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES Answer all questions. You are not allowed to start working with the apparatus for the first 15 minutes of the 2 hours allowed for this paper.


2mks EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY PRACTICAL Paper 3 CONFIDENTIAL INSTRUCTIONS TO SCHOOLS In addition to the normal fittings and apparatus in the laboratory, each candidate would need the following: Solid P in a boiling tube 100 cm3 of solution Q 1 Burette 1 Pipette 1 Filter funnel 1 Label 1 Pipette filler 1 Thermometer 250 cm3 volumetric flask 1 Conical flask 1 Test tube holder Water bath 1g Solid E 4cm3 liquid G supplied in a test tube 1 Boiling tube 6 test tubes in a test tube rack Distilled water in a water bottle 2 Filter papers 10cm3 measuring cylinder 1 blue and 1 red litmus papers 1 wooden splint 1 Watch glass ACCESS TO Source of heat Phenolphthalein indicator supplied with a dropper 2M sodium hydroxide solution supplied with a dropper 2M ammonia solution supplied with a dropper Sodium chloride solution supplied with a dropper Barium nitrate solution supplied with a dropper Nitric v acid supplied with a dropper Acidified potassium manganate vii supplied with dropper Universal indicator supplied with a dropper pH chart PREPARATION Solution Q is 0.2M sodium hydroxide Solid P is 4.5 g oxalic acid supplied in a boiling tube Solid E is a mixture of 0.5g aluminium sulphate and 0.5 g zinc carbonate. Liquid G is 4 cm3 of ethanol supplied in a stoppered test tubewww.freekcsepastpapers.comPage 27 EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY Paper 3 PRACTICAL TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES Answer all questions. You are not allowed to start working with the apparatus for the first 15 minutes of the 2 hours allowed for this paper. This time is to enable you to read the questions paper and make sure you have all the chemicals and apparatus that you may need.


Liquid G is 4 cm3 of ethanol supplied in a stoppered test tubewww.freekcsepastpapers.comPage 27 EASTERN CLUSTER EVALUATION - 2023 Kenya Certificate of Secondary Education K.C.S.E 233 3 CHEMISTRY Paper 3 PRACTICAL TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES Answer all questions. You are not allowed to start working with the apparatus for the first 15 minutes of the 2 hours allowed for this paper. This time is to enable you to read the questions paper and make sure you have all the chemicals and apparatus that you may need. All working must be clearly shown where necessary. 1. You are provided with:- 4.5g of solid P in a boiling tube. Solution Q, 0.2M sodium hydroxide. Phenolphthalein indicator. You are required to determine: i Solubility of solid P at different temperatures. Ii The value of n in the formula HX n 2H2Oof solid P. Procedure I a Fill the burette with distilled water. Using the burette, add 4.0cm3 of distilled water to solid P in a boiling tube. Heat the mixture in a water bath while stirring with a thermometer to about 700C until all the solid dissolves. B Allow the solution to cool while stirring with the thermometer and note the temperature at which crystals of solid P start to appear. Record this temperature in table I. c Using the burette, add 2.0cm3 of distilled water to the contents of the boiling tube. Heat the mixture in a water bath while stirring with the thermometer until all the solid dissolves. D Allow the mixture to cool while stirring and note the temperature at which crystals of solid P start to appear. E Repeat the procedure c and d three more times, heating the solution in a water bath and record the temperature in the table I. Retain the contents of the boiling tube for use in procedure II. F Complete the table by calculating the solubility of solid P at the different temperatures.


E Repeat the procedure c and d three more times, heating the solution in a water bath and record the temperature in the table I. Retain the contents of the boiling tube for use in procedure II. F Complete the table by calculating the solubility of solid P at the different temperatures. The solubility of a substance is the mass of that substance that dissolves in 100cm3 100gm of water at a particular temperature. TABLE I Volume of water in boiling tube cm3 Temperatures at which crystals of solid P first appear 0C Solubility of solid P g 100g of water 4 6 8 10 12 5mks i On the grid provided, plot a graph of solubility P against temperature. 3mks ii Using your graph, determine the temperature at which 100g of solid P would dissolve in 100cm3 of water. 1mk iii Determine the solubility of solid P at 550C. 1mk Procedure II Transfer the contents of the boiling tube from Procedure I into 250ml volumetric flask. Rinse the boiling tube and the thermometer with distilled water and add to the volumetric flask. Add more distilled water to make up the mark. Label this solution P. Fill the burette with solution P. Using a pipette and pipette filler place 25.0cm3 of solution Q into a conical flask. Titrate solution Q with solution P using phenolphthalein indicator. Www.freekcsepastpapers.comPage 28 Table II I II III Final burette reading cm3 Initial burette reading cm3 Volume of P used cm3 4mks Calculate the: i Average volume of solution P used in the experiment. 1mk ii Number of moles of sodium hydroxide used in solution Q. 1mk iii Concentration of solution P in moles per dm3 given that the relative formula mass of P, HX n 2H2O is 126. 2mks iv Number of moles of HX n 2H2O used in solution P. 1mk v The number of moles of sodium hydroxide required to react with one mole of P.


A Give the name of the Structure. 1mk b What is the total number of electrons used for bonding in a molecule of the structured Named in a 2mks 8. The purple color of a solution containing manganese vii ions disappears when iron ii ions are added. The ionic equation for the reaction which occurs is; MnO 4 aq 5Fe2 aq 8H aq Mn2 aq 5Fe3 aq 4H2O l With reasons state which substance is acting as a; 2 mks i Reducing agent. Ii Oxidizing agent. Www.freekcsepastpapers.comPage 40 9. 3.1g of an organic compound containing carbon, hydrogen and oxygen only produced 4.4g of carbon iv and 2.0 of water on combustion a Calculate its empirical formulae 2mk b Calculate its molecular formula if its mass 90. 1mk 10. Esters, fats and polyesters all contain the ester linkage. The structural formula of the ester is given below. Name two chemicals that could be used to make this ester and draw their structural formulae. Show all bonds. 2mks 11. An iron sculpture was produced to commemorate the anniversary of founder of a certain village. To prevent it from rusting, the village elder attached it by a wire to a block of zinc which was stored underground out of sight. I Explain how the village elder s action would prevent the rusting of the sculpture. 1mk ii What name is given to this method of preventing rusting? 1mk iii List down two other ways in which rusting of the statue could be prevented. 1mk 12. 50cm3 ammonia gas diffuses through a small orifice in 20 seconds. How long will it take a similar volume of propane C3H8 to diffuse through the same orifice under the same conditions of temperature and pressure? C 12.0, H 1.0, N 14.0 3mks 13. A what observations would be made if hydrogen sulphide gas was bubbled through a solution of Copper II sulphate.


The letters do not represent the actual symbols of elements. R S N Q T U P a Indicate in the grid the position of an element represented by letter V, whose atomic number is 14. 1mk b Select a letter which represents a monoatomic gas. 1mk c Write an equation for the reaction between Q and T 1mk 17. The table below shows ammeter readings recorded when two equimolar solutions were tested separately. Electrolyte Current A Dilute Sulphuric VI Acid Ethanoic Acid 7.2 4.0 Explain the difference in the ammeter readings. 1mk www.freekcsepastpapers.comPage 41 18. A student set up the apparatus for the preparation of carbon IV oxide gas as shown below. Study the set up and answer the questions that follow. A Explain using an equation why the reaction in apparatus Y occurs for a very short time then stops. 1mk b What is the purpose of passing the gas through potassium hydrogen carbonate? 1mk c State and explain why there is no sample of carbon IV oxide gas collected. 1mk 19. Describe how a solid of ammonium sulphate can be prepared starting with 100cm3 of 2M ammonium hydroxide 20. Study the scheme below and answer the questions that follow. A Write an equation for the formation of white fumes Y. 1 mk b What is the function of solid W in the reaction? 1 mk c Identify gas V. 1 mk 21. Explain the effect of the following on the rate of reaction in terms of the collisions theory; 3mks a Increase in concentration b Change in pressure c Use of catalyst 22. Explain each of the following observations. A Soft drinks fizz when the cap is removed from the bottle. 1mk b Diamond does not conduct electricity while graphite does. 1mk c Pure nitric V acid is colourless but during its laboratory preparation, it appears yellow. 1mk 23. Polyvinyl chloride PVC is an example of an addition polymer whose monomer is Chloroethene. A What is a polymer? 1mk b What is meant by addition polymerization?


The grid below shows part of the periodic table. Study it and answer the questions that follow. The letters do not represent the true symbols of the elements. I II III IV V VI VII VIII a b Which element forms ions with charge of -2? Explain your answer. 2mks c Which element is the most reactive metal? 1mk d Name the chemical family to which element B and G belong. 1mk e What is the nature of the oxide formed by C? 1mk f How does the reactivity of H compare with that of E? Explain. 2mks g Write a balanced equation between B and Chlorine. 1mk h Explain how the atomic radii of F and G compare. 2mks i If the oxides of B and D are separately dissolved in water, what effects will their aqueous solutions have on litmus paper? 2mks 2. A i State what is meant by dynamic equilibrium . 1mk ii Dichromate VI ions are orange in colour while chromate VI ions are yellow. Consider the following equilibrium. Cr2 7 2 2OH- aq 2Cr 4 2 2H2O 1 State and explain the observations that will be made if sulphuric VI acid is added to the mixture. 2mks b One of the reactions in the manufacture of Nitric V acid involves catalytic oxidation of ammonia as shown in the equation. 4NH3 g 502 g 4NO g 6H2O g ; -90kjmol-1 The reaction is carried out at a pressure of 10 atmospheres and a temperature of 9000C. i Other than Nitric V acid, name another product that is formed. 1mk ii State and explain the effect on the position of equilibrium if the reaction is carried out; I at 10 atmospheres pressure and 4500C. 2mks II at 9000C and 20 atmospheres pressure.


I Other than Nitric V acid, name another product that is formed. 1mk ii State and explain the effect on the position of equilibrium if the reaction is carried out; I at 10 atmospheres pressure and 4500C. 2mks II at 9000C and 20 atmospheres pressure. 2mks III In the absence of a catalyst. 1mk c State and explain the effect on the rate of the reaction if the reaction is carried out at 10 atmospheres and 4500C. 2mks d A factory uses 100kg of ammonia each day to produce 160kg of nitrogen II oxide. Calculate the percentage yield of nitrogen II oxide. 3mks A K B C D E F G Hwww.freekcsepastpapers.comPage 44 3. The scheme below shows reactions of some organic compounds. Study it and answer the following questions. A Give the name and draw the structural formula of compound P. 2mks b Give the reagents and conditions necessary for carrying out:- i Step I 1mk ii Step II 2mks c Give the name of the type of reaction that takes place in:- i Step 1 ii Step II iii Step IV d Name reagent Q. e Write an equation forming compound T 1Mk f Draw the structural formula of M and give its name 1Mk g I Name compound K 1Mk II If the relative molecular mass of K is 84,000, determine the value of n C 12, H 1 2Mks 4. The following data was obtained during an experiment to determine the molar heat of combustion of methanol. Volume of water used 100cm3 Initial temperature of water 220C Final temperature of water 380C Mass of methanol Lamp before burning 88.10g Mass of methanol Lamp after burning 87.78g a Calculate:- i The highest temperature change.


E Write an equation forming compound T 1Mk f Draw the structural formula of M and give its name 1Mk g I Name compound K 1Mk II If the relative molecular mass of K is 84,000, determine the value of n C 12, H 1 2Mks 4. The following data was obtained during an experiment to determine the molar heat of combustion of methanol. Volume of water used 100cm3 Initial temperature of water 220C Final temperature of water 380C Mass of methanol Lamp before burning 88.10g Mass of methanol Lamp after burning 87.78g a Calculate:- i The highest temperature change. 1mk ii The mass of methanol burnt 1mk iii The number of moles of methanol used in the experiment C 12, O 16, H 1 . 1mk iv The heat change in the experiment. 2mks Density of water 1g cm3, specific heat capacity of water 4.2 Jg-1K-1 v The molar heat of combustion of methanol. 2mks vi Write the thermochemical equation for the combustion of methanol. 1mk vii In the space provided, sketch a simple energy level diagram for the above change, showing activation energy. 2mks 5. A Study the standard electrode potentials for the half cells given below and answer the questions that follow. The letters do not represent the actual symbols of the elements . Half cells E Volts N aq e N s -2.92 J aq e J s 0.52 K aq e K2 g 0.00 G2 g e G- aq 1.36 M2 aq 2e M s -0.44 i Identify the strongest reducing agent. Give a reason for your answer. 1mk ii Which two half cells would produce the highest potential difference when combined.


Half cells E Volts N aq e N s -2.92 J aq e J s 0.52 K aq e K2 g 0.00 G2 g e G- aq 1.36 M2 aq 2e M s -0.44 i Identify the strongest reducing agent. Give a reason for your answer. 1mk ii Which two half cells would produce the highest potential difference when combined. 1mk iii Explain whether the reaction represented below can take place. 2mks 2N aq M s 2N s M2 aq www.freekcsepastpapers.comPage 45 b 100cm3 of 2M Sulphuric VI acid was electrolyzed using the set-up represented by the diagram below. I Name electrode A and B 1mk ii Write an equation for the reaction that produces gas L. 1mk iii Describe how gas K can be identified. 1mk iv Explain the difference in. I The volume of the gases produced at the electrodes. 1mk II Brightness of the bulb if 100cm3 of 2M ethanoic acid was used in place of sulphuric VI acid. 1mk 6. A The diagram below was used to prepare hydrogen chloride gas which was passed over heated iron powder. I Give a pair of reagents that will produce hydrogen chloride gas in flask A. 1mk ii Name the substance in flask B. 1mk iii State the observation made in the combustion tube. 1mk iv Write an equation for the reaction in the combustion tube. 1mk b i Identify the gas that burns at the jet. 1mk ii Explain why the gas in b i is burned. 1mk c Give reasons why excess hydrogen chloride gas is dissolved using the funnel arrangement. 1mk d State what will be observed when the reaction in the combustion tube is complete. 1mk www.freekcsepastpapers.comPage 46 7.


1mk c Give reasons why excess hydrogen chloride gas is dissolved using the funnel arrangement. 1mk d State what will be observed when the reaction in the combustion tube is complete. 1mk www.freekcsepastpapers.comPage 46 7. A Define radioactivity. 1mk b Give two differences between chemical and nuclear reactions. 2mks c Study the diagram below and answer the questions that follow. I What property of radiations is being investigated by the illustration above. 1mk ii Give the name of the radiation B and give a reason. 1mk e Below is the radioactive decay starting with 21483 Bi, study it and answer the questions that follow. I Identify the radiations emitted at: - 1mk Step 1 Step V ii Write a nuclear equation for step II. 1mk e State one application of radioactivity in: - i Medicine 1mk ii Agriculture 1mk f State two dangers associated with radioactivity. 1mk g The decay rates of a sample of radioisotope of Bismuth at different time. Intervals as indicated in the following table. Time Hours 0 5 10 15 20 25 Rate of disintegration in counts 5-1 730 570 455 365 292 232 i Draw a graph of disintegration rate against time. 3mks ii Determine the half-life of Bismuth. 1mk www.freekcsepastpapers.comPage 47 LUGARI JOINT EVALUATION EXAMINATION, 2023 233 3 Chemistry Paper 3 PRACTICAL CONFIDENTIAL In addition to the apparatus and fittings found in a chemistry laboratory, each candidate will require the following: 1. About 100cm3 of 0.2m hydrochloric acid labelled solution S 2. Accurately weighed 2.4g of anhydrous sodium carbonate. 3. 250ml volumetric flask 4. 50ml measuring cylinder 5. Distilled water 6. 250ml empty beaker 7. Glass rod 8. About 50cm3 of 0.5m sulphuric VI acid labelled solution G 9.


250ml empty beaker 7. Glass rod 8. About 50cm3 of 0.5m sulphuric VI acid labelled solution G 9. About 70cm3 of 1m sodium hydroxide solution labelled solution F 10. 10ml measuring cylinder 11. 100ml empty beaker 12. 0-110 C thermometer 13. One burette 0-50ml 14. One 25.0ml pipette 15. One pipette filler 16. Retort stand 17. 2 labels 18. Two conical flasks 250ml 19. One boiling tube 20. Six dry test tubes in a test tube rack 21. Methyl orange indicator 22. One filter funnel 23. A white tile 24. Metallic spatula 25. 1.5 g of solid C 26. 1g of solid P 27. About 0.5g anhydrous sodium carbonate. Access to i Means of heating ii 2m NaoH solution with a dropper iii 2m ammonia solution with a dropper iv 0.5m sodium chloride solution with a dropper v 1m sulphuric VI acid with a dropper NOTE 1. Solid C is lead ii nitrate 2. Solid P is oxalic acid 3. Solution F is sodium hydroxide solution prepared by dissolving 40g of it in 1 litre of solution 4. Solution S is 0.2m Hydrochloric acid prepared by dissolving 17.2cm3 of concentrated hydrochloric acid in 1 litre. 5. Solution G is 0.5m sulphuric vi acid prepared by dissolving 27.5cm3 of concentrated sulphuric vi acid in 1 litre of solution Density 1.84g cm3 6.


Solution S is 0.2m Hydrochloric acid prepared by dissolving 17.2cm3 of concentrated hydrochloric acid in 1 litre. 5. Solution G is 0.5m sulphuric vi acid prepared by dissolving 27.5cm3 of concentrated sulphuric vi acid in 1 litre of solution Density 1.84g cm3 6. 0.5m sodium chloride solution is prepared by dissolving 29.25g of solid sodium chloride in 1 litre of solutionwww.freekcsepastpapers.comPage 48 LUGARI JOINT EVALUATION EXAMINATION, 2023 233 3 Chemistry Paper 3 Practical 2 HRS INSTRUCTIONS TO CANDITATES a Answer all the questions b You are NOT allowed to start working with the apparatus for the first 15 minutes of the 2 hrs allowed for this paper. This time is to enable you to read the question paper and make sure you have all the chemicals and apparatus that you may need. C All working must be clearly shown where necessary. 1. You are provided with - Solution S 0.2m Hydrochloric acid solution - N grams of anhydrous sodium carbonate - Methyl orange indicator You are required to prepare a solution of sodium carbonate and then standardize it with hydrochloric acid solution. Procedure Transfer all the N grams of sodium Carbonate into a 250ml volumetric flask Add 100cm3 of distilled water and shake till all the solid dissolves. Add more distilled water up to the 250ml mark and label it solution P using a measuring cylinder, transfer 50cm3 of solution P into a clean 250ml beaker and add 50cm3 of distilled water. Stir well with a glass rod and label it solution T. Pipette 25.0cm3 of solution T and place it into a conical flask, add 3 drops of methyl orange indicator and titrate with solution S from the burette. Record your results in the table I below. Repeat the titration two more times and complete the table below.


Pipette 25.0cm3 of solution T and place it into a conical flask, add 3 drops of methyl orange indicator and titrate with solution S from the burette. Record your results in the table I below. Repeat the titration two more times and complete the table below. 3mks I II III Final burette reading cm3 Initial burette reading cm3 Volume of S used cm3 a Calculate the average volume of solution S used 1mk b i Calculate the number of moles of solution S used. 2mks ii Write a balanced chemical equation for the reaction between solution T and S 1mk iii Calculate the number of moles of sodium carbonate solution in 25cm3 of solution T. 2mks iv Calculate the number of moles of sodium carbonate in 100cm3 of solution T 2mks v Calculate the number of moles of sodium carbonate in 50cm3 of the original solution P 1mk c Given that Na 23.0, C 12.0, O 16.0 Calculate i. The mass of sodium carbonate N grams that were dissolved to make solution P 2mks ii. The concentration of sodium carbonate solution P in moles per litre 2mks 2. You are provided with 1M sodium hydroxide solution F. 0.5m Solution of an acid solution G. You are required to determine the molar heat of neutralization of sodium hydroxide with acid G. Procedure Place six test tubes on the test tube rack. Using 10cm3 measuring cylinder measure 5cm3 portions of solution G and place them into each of the six test tubes. Measure 25cm3 of solution F using a 50cm3 measuring cylinder and place it into a 100cm3 beaker. Measure the temperature of this solution F and record it in table II below. Pour the first portion of the 5cm3 of solution G from the test-tube into the beaker containing 25cm3 of solution F. Stir with the thermometer and record the highest temperature of the mixture pour the second portion of solution G, stir carefully and record the highest temperature of this mixture.


2mks 2. State two functions of a fume chamber in a laboratory. 2mks 3. The diagram below shows a structure of water molecule. 4. Two samples of water were put in separate beakers. They were boiled for some time and allowed to cool. Equal volumes of soap were added to each sample and stirred. Water in beaker C readily formed lather with soap while water in beaker D required more soap to lather. I Write the formula of one salt likely to be in water in beaker. 2mks a C b D ii Name one method that can be used to soften water in beaker D. 1mk 5. Describe how you would prepare lead ii sulphate given the following reagents: dilute nitric v acid, distilled water, sodium sulphate solid and lead metal. 3mks 6. During manufacture of sulphuric vi acid, sulphur iv oxide is oxidised to sulphur vi oxide in the presence of vanadium oxide catalyst as shown below: The reaction is carried out at a pressure of 3 atmospheres and a temperature of 4500C. State and explain the effect on the yield of sulphur vi oxide if the reaction is: a Carried out at 3 atmospheres and 6000C. 2mks b In absence of a catalyst. 2mks 7. A Hydrogen gas was passed over 4.64g of an oxide of iron in a combustion tube until there was no further change. The mass of the final substance was found to be 3.36g. Determine the empirical formula of the oxide. Fe 56, O 16 . 3mks b State the property of hydrogen demonstrated in the experiment above. 1mk 8. Atoms of element X exist as 14 6X and 12 6 X. a What name is given to the two types of atoms? 1mk b Use dot and x diagram to represent electrons draw the atomic structure of x. 2mks 9. Hydrogen sulphide gas was passed through a solution of iron ii chloride. I State two observations made.


2mks 9. Hydrogen sulphide gas was passed through a solution of iron ii chloride. I State two observations made. 2mks ii Write an equation for the reaction taking place in i above. 1mk 10. Two clean iron nails of the same size were connected with wire to magnesium and silver stripes as shown. State and explain the observation made on nail x and y if they were left in the open for 2 weeks. 2mks Name the bonds labelled. 2mks i A ii Bwww.freekcsepastpapers.comPage 59 11. The diagram below shows an incomplete setup used to prepare sulphur iv oxide in the laboratory. A Identify solid H. 1mk b Complete the set up above to show how dry sulphur iv oxide may be collected. 2mks 12. Some average bond energies are given below. Bond Energy in kJ MOL C-C 348 C-H 414 Cl- Cl 243 H-Cl 340 C Cl 432 Determine whether the reaction below is exothermic or endothermic. 3mks C2 H6 g Cl2 g C2H5Cl g HCl g 13. Study the scheme below and answer questions that follow. 14. Ethanedioic acid H2C2O4 is used instead of methanoic acid HCOOH to prepare carbon ii oxide in the laboratory. It gives equal volume of carbon ii oxide and carbon iv oxide. A Write an equation for the dehydration of ethanedioic acid. 1mk b Explain how pure carbon II oxide can be obtained from the mixture. 2mks 15. The diagram below represents a set-up of apparatus used to investigate the effect of an electric current on lead ii bromide. A Describe the observation made at electrode C. 2mks b State two applications of electrolysis. 1mk a Identify reagent A. 1mk b Name process B 1mk c What does PVC stand for? 1mk www.freekcsepastpapers.comPage 60 16. The set up below was used to investigate a property of ammonia gas.


1mk b Name process B 1mk c What does PVC stand for? 1mk www.freekcsepastpapers.comPage 60 16. The set up below was used to investigate a property of ammonia gas. I What property of ammonia gas is being investigated? 1mk ii The experiment above is commonly known as the fountain experiment ; explain. 2mks iii Identify another gas that may be used instead at ammonia gas. 1mk 17. Draw a well labelled diagram to show how crystals of sodium chloride can be obtained from sodium chloride solution. 3mks 18. A Define the term solubility. 1mk b 40g of a saturated solution yields 15g of salt when evaporated to dryness. Calculate the solubility of the salt. 2mks 19. Increased levels of carbon ii oxide leads to global warming. Give two reasons why the amount of carbon iv oxide in the atmosphere is increasing gradually. 2mks 20. Explain the observation made when a blue litmus paper is dipped in methylbenzene in which hydrogen chloride gas is bubbled through. 2mks 21. The reaction between hydrogen gas and oxygen releases energy. A student drew the reaction profile for the reaction between hydrogen gas and oxygen gas. State two errors made when drawing the reaction profile. 2mks 22. Both water 18 and hydrogen sulphide 34 are molecular substances. However water has a higher boiling point than hydrogen sulphide. Explain. 2mks 23. The grid below represents part of a periodic table. Study it and answer the questions that follow. E A X R G C Q a How do the atomic radii of R and G compare. 1mk b How do the pH of the oxides of A and E compare. 1mk c On the grid, indicate with a tick the position of K which is found on the third period and forms K3- ions. 1mk www.freekcsepastpapers.comPage 61 24. The curves below were obtained when equal volumes of nitric v acid of same concentration were reacted with 25.0g of calcium carbonate, labelled Y. In one case, the acid was first warmed before the reaction.


1mk www.freekcsepastpapers.comPage 61 24. The curves below were obtained when equal volumes of nitric v acid of same concentration were reacted with 25.0g of calcium carbonate, labelled Y. In one case, the acid was first warmed before the reaction. A Which curve represents the reaction involving warm nitric v acid? 1mk b Sketch the curves obtained if the graph of the volume of CO2 produced against time were plotted. NB: on the same axis . 2mks 25. I State two observations made when a small piece of potassium metal is put in a beaker full of water. 2mks ii Name the group of the periodic table to which potassium belongs. 1mk 26. When a hydrocarbon with formula CxHy burns in chlorine gas, black specks and a colourless gas are obtained. A To which homologous series does the hydrocarbon belong? 1mk b Write the general equation for the reaction between the hydrocarbon and chlorine gas. 1mk 27. The diagram below represents a set up for large scale manufacture of hydrochloric acid. Study it and answer the questions that follow. I Name the substance X. 1mk ii What is the purpose of glass beads? 1mk iii Give one use of hydrochloric acid. 1mk 28. When 25cm of 0.5M HCl is added to 25cm of 0.5M NaOH, the temperature of the solution rose from 230C to 260C. Given that the density of the solution is 1g cm and its specific heat capacity is 4.2Jg 1k 1. A Determine the amount of heat evolved that caused the temperature to rise. 1mk b Work out the molar enthalpy of neutralization for this reaction. 2mks www.freekcsepastpapers.comPage 62 BUURI FORM 4 JOINT EXAMINATION, 2023 233 2 Chemistry PAPER 2 TIME: 2 HOURS Instructions to candidates 1. Answer all the questions. 2. Mathematical tables and scientific calculators may be used. 3. All working must be clearly shown where necessary. 1. The diagram shows part of the Periodic Table.


All working must be clearly shown where necessary. 1. The diagram shows part of the Periodic Table. The letters are not the actual symbols of the elements. A Compare the reactivity between elements Q and T. 2mks b Explain the electrical conductivity of the chloride of element T. 2mks c Compare the melting and boiling points of elements R and S. 2mks d Write an equation for the second ionization energy of element Q. 1mk e How does the atomic and ionic radius of each of the following elements compare? I Element T. 1 mks ii Element P 1 mks f Compare atomic radius of elements R and Q. 1 mks g Explain the difference in the melting points of the oxides of element Q and the oxide of element R. 1 mks 2. A The diagram below shows the structure of an allotrope of sulphur b Study the flow chart below and answer the questions that follow. I Write the equation for the reactions in: I. Step I. 1mk II. Step II. 1mk ii State two observations made in step II. 2mks iii Explain the observations made in: I. Step IV. 1 mks II. Step V. 1 mks iv State one use of gas T. 1mk i What are allotropes? 1mk ii Identify the allotrope shown in the diagram above. 1mk iii State two properties of the allotrope above. 2mks www.freekcsepastpapers.comPage 63 3. Next to each letter, A to F, in the table below is the molecular formula of an organic compound. A Choose a molecular formula above that represents an organic compound below. Write down only the letter A to F next to the question numbers i A haloalkane mk ii An alcohol mark iii An unsaturated hydrocarbon mark iv A product of thermal cracking of compound C.


Next to each letter, A to F, in the table below is the molecular formula of an organic compound. A Choose a molecular formula above that represents an organic compound below. Write down only the letter A to F next to the question numbers i A haloalkane mk ii An alcohol mark iii An unsaturated hydrocarbon mark iv A product of thermal cracking of compound C. mark b If compound F is a carboxylic acid, write down the following: i The structural formula of a functional isomer an isomer with a different functional group of F. 1mk ii The IUPAC name of a functional isomer of F. 1mk c Compound B is a monomer used to make a polymer. Write down the: i Definition of a polymer. 1mk ii IUPAC name of the polymer. 1mk iii Balanced equation for the polymerisation reaction 1mk d Compound A is used as a reactant in the production of compound D. i Name the type of reaction that takes place. 1mk ii State two changes that can be made to the reaction conditions in d i to obtain compound B, instead of D, as product. 2mks 4. The flow chart below summarizes the extraction of Zinc, study it and answer the questions that follow. A Name the process represented by A and B 2mks b Identify the reagents required for process B, C and D 3mks c Write a chemical equation of the reaction that occurs in process B 1mk d With an aid of a diagram, explain how you would obtain a pure sample of Zinc by process E. 2mks e State two uses of Zinc metal 2mks 5. A The table below gives some values of standard enthalpies of formation Hf .


A Name the process represented by A and B 2mks b Identify the reagents required for process B, C and D 3mks c Write a chemical equation of the reaction that occurs in process B 1mk d With an aid of a diagram, explain how you would obtain a pure sample of Zinc by process E. 2mks e State two uses of Zinc metal 2mks 5. A The table below gives some values of standard enthalpies of formation Hf . Substance F2 g CF4 g HF g Hf kJmole 1 0 680 269 The enthalpy changes for the reaction C2H6 g 7F2 g 2CF4 g 6HF g is 2889 kJ mol 1. Use this value and the standard enthalpies of formation in Table 2 to calculate the standard enthalpy of formation of C2H6 g . 3mks b In an experiment to determine the enthalpy of solution of concentrated sulphuric VI acid Specific gravity 1.84gcm-3 the following procedure was used: - A clean 250.0 cm3 glass or plastic beaker is wrapped with a newspaper leaf. -. About 50.0 cm3 of tap water is measured into the beaker and the steady temperature noted. -. The beaker is held in a tilted position and 2.0 cm3 of and sulphuric acid added into the waterwww.freekcsepastpapers.comPage 64 i Why was the beaker wrapped with newspaper leaf? 1mk ii Why was the acid added into water and not vice versa? 1mk iii Explain the reason for tilting the beaker during addition of the acid into water. 2mks iv Calculate the molar enthalpy of solution of concentrated sulphuric VI acid given that T for the reaction T 1oC. Density of water 1gcm-3; specific heat capacity of water 4.2kJkg-1K-1 . 4mks 6.


2mks iv Calculate the molar enthalpy of solution of concentrated sulphuric VI acid given that T for the reaction T 1oC. Density of water 1gcm-3; specific heat capacity of water 4.2kJkg-1K-1 . 4mks 6. A Consider the electrochemical cell represented by the cell notation below, where X is an unknown metal: Pt s Fe2 aq , Fe3 aq X aq X s The cell potential of this cell was found to be 0.03 V. i Write down the type of electrochemical cell illustrated above. 1mk ii What does the single line in the above cell notation represent? 1mk iii Write down the half-reaction that takes place at the anode in the above cell. 1mk iv Given that: Half reaction E volts Fe3 aq e Fe2 aq 0.77 Ag aq e Ag s 0.80 Na aq e Na s 2.87 K aq e K s 2.92 Identify X with the aid of a calculation. 2mks b The diagram below shows the apparatus that can be used to electrolyse dilute Sulphuric acid. Study it to answer the questions that follow. I Identify the gases H and G I. H 1mk II. G 1mk ii What happens to the concentration of the Sulphuric acid during the process with time? Explain 2mks iii During the electrolysis a current of 0.72A was passed through the electrolyte for 15 minutes. Calculate the volume of gas H produced. 1 Faraday 96,500C, molar gas volume 24 dm3 at r.t.p . 3mks 7. A i What is a salt? 1mk ii Write the formula of any two double salts. 1mk b A student has found that her sample of potassium nitrate is contaminated with small amounts of a green solid.


A i What is a salt? 1mk ii Write the formula of any two double salts. 1mk b A student has found that her sample of potassium nitrate is contaminated with small amounts of a green solid. She picks out a small piece of the green solid and finds that it is insoluble in water. I Describe how you would make a pure sample of potassium nitrate from the impure mixture. 3mks ii The student believes that the green solid is copper II carbonate. Describe a series of 3 tests that the student could use to confirm this. 6 marks Test Procedure Observations Conclusion 1 2 3 c In an experiment 50g of a saturated solution of a salt X was heated to dryness in an evaporating dish. The mass of crystals when weighed gave a reading of 2.7g. Determine the solubility of the salt. 2mks www.freekcsepastpapers.comPage 65 BUURI FORM 4 JOINT EXAMINATION, 2023 233 3 Chemistry PAPER 3 Practical CONFIDENTIAL Requirements for candidates In addition to the apparatus and fittings found in a Chemistry laboratory, each candidate will require the following. 1. About 100cm3 of solution F 2. About 50cm3 of solution G 3. 30cm3 of solution M 4. 30cm3 of solution N 5. One burette 0 50ml 6. One pipette 25ml 7. Two conical flasks 8. 100ml measuring cylinder 9. 200ml or 250ml beaker 10. About 500ml distilled water 11. Phenolphthalein indicator 12. Thermometer 0 1100C 13. Source of strong heat preferably Bunsen burner 14. Clock or stop watch 15. 2 boiling tubes 16. One CLEAN METALLIC spatula 17. 6 clean dry test-tubes 18. One test-tube holder 19. At least 6cm length of universal indicator paper 20. 0.5g of sodium hydrogen carbonate 21. PH chart pH 1 14 22. Bromine water supplied with a dropper 23. 0.5g of solid K oxalic acid. 24.


Bromine water supplied with a dropper 23. 0.5g of solid K oxalic acid. 24. 0.5g of solid P Sodium sulphite The students should have access to the following a. 2.0M NaOH solution with a dropper b. 1.0M barium nitrate solution with a dropper c. Bromine water with a dropper d. Acidified potassium manganate vii with a dropper e. 2.0M HCl with a dropper 1. Bromine water is prepared by adding 1ml of liquid bromine to 100cm3 of distilled water and shaking thoroughly in a fume cupboard. 2. Acidified potassium permanganate is prepared by adding 3.16g of solid potassium permanganate to 400cm3 of 2M sulphuric acid and diluting to one litre of solution using distilled water. 3. Solution M is made by dissolving 12.6g of oxalic acid in 400cm3 distilled water and making it to 1 litre. 4. Solution N is prepared by dissolving 3.16g of potassium manganate VII in 200cm3 of 2M sulphuric acid and adding more water to make 1 litre 5. Solution F is prepared by dissolving 4g of sodium hydroxide pellets in about 800cm3 of distilled water and diluting it to one litre solution. 6. Solution G is prepared by dissolving 9.0g of oxalic acid ethan-1,2-dioic acid in 200cm3 of distilled water and diluting it to 250cm3 solution. Www.freekcsepastpapers.comPage 66 BUURI FORM 4 JOINT EXAMINATION, 2023 233 3 Chemistry Paper 3 TIME: 2HRS 15MINS INSTRUCTIONS TO CANDIDATES 1. Answer all the questions. 2. All working must be clearly shown where necessary. 3. You are not allowed to start working with the apparatus for the first 15 minutes. This time is to enable you read the question paper and make sure you have all the requirements. 1.


1 mark b 50cm3 of carbon IV oxide diffuses through a porous plate in 15 seconds. Calculate the time taken by 75cm3 o nitrogen IV oxide to diffuse through the same plate under similar conditions. C 12, O 16, N 14 3 marks 21. A Give equations to show the reactions that take place when: i Magnesium reacts with dilute hydrochloric acid. 1 mark ii Iron reacts with steam. 1 mark b Give one industrial use of the gas produced in the reactions in a i and a ii above. 1 mark 22. The grid below is a section of the periodic table. The letters do not represent the actual symbol of the elements. Use it to answer the questions that follow. K C F H D E G I J a How does the electronegativity vary from H to J. 1 mark b Give the formula of the compound between E and J. 1 mark c State the nature of the oxide formed by E. 1 mark 23. Potassium consists of three isotopes with mass numbers Y, 40 and 41 having relative abundances 93.1 , 0.01 and 6.89 respectively. Determine the value of Y given the atomic number of potassium is 19 and its relative atomic mass is 39.1379 3 marks 24. The set up below was used to react dry chlorine gas with iron powder. The product Z was collected in flask B. HeatProduct ZCalcium oxideFlask BDry Cl 2 g Iron powder a Identify product Z. 1 mark b i What property of product Z makes it possible to be collected as shown in the diagram. 1 mark ii Explain why calcium oxide is preferred to calcium chloride. 1 mark 25. A molecule of one of the elements is shown below. I Identify the element. 1 mark ii Explain why this element has a higher boiling point compared to that oxygen. 2 marks iii Write an equation to show the reaction between this element with oxygen. 1 mark 26. Boilers used for boiling hard water are normally covered with scales after some time. A What is the chemical name for boilers scales? 1 mark b How is the boiler scale removed?


Boilers used for boiling hard water are normally covered with scales after some time. A What is the chemical name for boilers scales? 1 mark b How is the boiler scale removed? 1 mark 27. State Charle s law. 1 mark www.freekcsepastpapers.comPage 80 IMENTI SOUTH EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 2 CHEMISTRY Paper 2 Theory TIME: 2 HOURS INSTRUCTIONS: Answer ALL the questions. Electronic calculators may be used. All working must be clearly shown where necessary. 1. The grid below shows part of the periodic table. Study it and answer the questions that follow. The letters does not represent the actual symbol of the elements P R Q V S T U a i Select an element that can form an ion with a charge of -2. 1 mark ii What type of structure will the chloride of Q have? 1 mark iii Explain how the reactivity of R and S can be compared. 2 marks b 2.5g of Q react completely with 1.2dm3 of gas R at s.t.p i Write a balanced equation for the reaction between Q and R. 1 mark ii Determine R.A.M of Q. Molar gas volume at s.t.p 22.4 dm3 3 marks c T and V reacts with oxygen to form an oxide. I State the nature of oxide of T and V 2 marks ii Write down the formula of the oxides formed between T and oxygen and V and oxygen. 2 marks 2. A The diagram below shows a set up used to obtain nitrogen gas in an experiment. IceLiquid RWaterNitrogen gasCopper II oxideTube KDry ammonia gas i Name liquid R. 1 mark ii What observation would be made in the tube K after heating for same time? 1 mark iii Write an equation for the reaction that took place in tube K. 1 mark b i If 320cm3 of ammonia gas reacted with copper II oxide, calculate the volume of nitrogen gas produced. 1 mark ii The mass of copper II oxide that reacted.


1 mark iii Write an equation for the reaction that took place in tube K. 1 mark b i If 320cm3 of ammonia gas reacted with copper II oxide, calculate the volume of nitrogen gas produced. 1 mark ii The mass of copper II oxide that reacted. Cu 63.5, O 16.0, 1 mole of a gas occupies 24 litres at r.t.p 2 marks iii At the end of the experiment the pH of the liquid R in the U-tube was found to be about 10.0. Explain. 1 mark c Why is it advisable to obtain nitrogen from air instead of ammonia? 1 mark www.freekcsepastpapers.comPage 81 d A beaker containing concentrated hydrochloric acid was brought near a gas jar containing concentrated ammonia solution. I What observation was made? 1 mark ii Write the equation for the reaction. 1 mark e State two uses of ammonia gas. 2 marks 3. The following is the procedure that was used to obtain the solubility of salt R in water at 25oC. Study it and answer the questions that follows. Salt R was dissolved in water until no more could dissolve. The mixture was then cooled to 25oC and allowed to settle. A dry evaporating dish and dry watch glass were weighed. Some of the solution was decanted into the dish, covered with the watch glass and then weighed. The solution was evaporated to dryness over a small flame. The residue, the dish and the watch glass were weighed. The residue was heated repeatedly until a constant mass was obtained. The below results were obtained: Mass of dish watch glass 50.60g Mass of solution dish watch glass 80.60g Mass of residue dish watch glass 62.60g a Use the data to answer the questions that follows. I What is the purpose of the watch glass in such an experiment? 1 mark ii Why would the heating be continued until a constant mass was obtained? 1 mark iii Calculate the mass of the solution. 1 mark iv Calculate the mass of the residue. 1 mark v Calculate the mass of water.


1 mark iii Calculate the mass of the solution. 1 mark iv Calculate the mass of the residue. 1 mark v Calculate the mass of water. 1 mark vi Calculate the solubility of salt R in g per 100g of water at 25oC. 2 marks b Hard water has both advantages and disadvantages. Give one advantage and one disadvantage. I Advantage 1 mark ii Disadvantage 1 mark c Using an equation, explain how addition of sodium carbonate is used to remove water hardness. 2 marks 4. A Two reagents that can be used to prepare chlorine gas are manganese IV oxide and concentrated hydrochloric acid. I Write an equation for the reaction. 1 mark ii Give the formula of another reagent that can be reacted with concentrated hydrochloric acid to give chlorine gas. 1 mark iii Describe how chlorine could be dried in the laboratory. 1 mark c In another experiments dry chlorine gas was reacted with aluminium as shown. HeatGuard tabDry chlorine gasAluminiumA i Name substance A. 1 mark ii Write an equation for the reaction that took place in the combustion tube. 1 mark iii 0.84g of aluminium reacted completely with chlorine gas. Calculate the volume of chlorine gas used. Al 27.0, Cl 35.5 3 marks iv Name one substance that can be put in the guard tube. 1 mark www.freekcsepastpapers.comPage 82 5. A student set up apparatus as shown below to determine the molar enthalpy of displacement for the reaction between zinc and copper II sulphate solution. ThermometerPolystyrene cup25cm of 0.2M copper II sulphatePlastic cup3 An excess of powdered zinc was added to 25cm3 of 0.2M copper II sulphate solution and stirred. The temperature of the solution was noted to have risen from 24oC to 32oC. a Define the term Molar heat of displacement. 1 mark b Explain why polystyrene cup was used instead of glass beaker. 1 mark c Write an ionic equation for the reaction that took place.