Chemistry Paper 2 Questions and Answers - Bunamfan Cluster Pre Mock Exam 2022

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Instructions To Candidates:

  • Answer all the questions in the spaces provided.
  • All working must be clearly shown where necessary.
  • Mathematical tables, Electronic calculators may be used.


    1. The grid below show part of the periodic table.(The letter do not represent the actual Symbols. Use it to answer the questions that follow.
      04 Chem p2q1
      1. Select the most reactive non-metal. (1mk)
      2. Select an elements that forms a divalent cation. (1mk)
      3. Element Z has atomic number 14.Show its position in the grid. (1mk)
      4. How do the atomic radii of U and J compare? (2mks)
      5. How do electrical conductivity of A and Y compare? (2mks)
      6. How does the boiling point of elements K, L and M vary? Explain (2mks)
    2. The table below gives information on four elements by letters V, X, E and G. Study it and answer the questions that follow. The letters do not represent the actual symbols of the elements.
      Element Electron arrangement Atomic radius Ionic radius
      V 2:8:2 0.136 0.065
      2:8:7 0.099 0.181
      E 2:8:8:1 0.203 0.133
      G 2:8:8:2 0.174 0.099

      1. Which two elements have similar properties? Explain. (2mks)
      2. Which element is a non-metal? Explain. (1mk)
      3. Which one of the elements is the strongest reducing agent. (1mk)
    1. Petrol is a mixture of several alkane molecules ranging from pentane (C5H12) to decane (C10H22).Name the process by which petrol is obtained from crude oil. (1mk)
    2. A decane molecule derived from petrol is cracked into hydrocarbon with equal number of carbon atoms in each molecule.
      1. What is cracking? (1mk)
      2. State two conditions necessary for the above process. (2mks)
      3. Write an equation for the cracking of decane molecule. (1mk)
      4. Draw and name two isomers of molecule with lower molecular mass obtained from cracking of decane as shown in b(iii) above. (2mks)
      5. How would you distinguish the products formed by cracking as shown in b(iii) in the laboratory. (2mks)
    3. Name the class to which the following cleansing agents belong.
      1. R-COONa+ (1mk)
      2. R- o -O-SO3Na (1mk)
    4. Which cleaning agent above is not environmental friendly? Explain. (2mks)
  3. Study the flow diagram below and use it to answer the questions that follow.
    04 Chem p2q3
    1. Give the name and formula of the following.
      1. White precipitate E
        Name……………………… ( ½ mk)
        Formula……………………… ( ½ mk)
      2. Colourless solution F
        Name ………………………………… ( 1mk)
    2. What property is exhibited by white precipitate E when it reacts with Sodium hydroxide and HCl acid. (1mk)
    3. Write an ionic equation for the reaction between white precipitate E and excess sodium hydroxide solution. (1mk)
    4. The information below gives the solubilities ( In g/100g of water) of substances X and Y at various temperatures
      Temeprature   0 20 40 60 80 100
       Solubility g/100g of water X 10 15 26 40 63 100
      Y 30 34 37 40 44 48

      1. Plot a graph of solubility against temperature for the two salts X and y on the same axis. (4mks)
      2. From the graph state:
        1. The solubility of X at 50°C (1mk)
        2. The temperature at which solubility of Y is 36g/100g of water. (1mk)
        3. Calculate the mass of crystals of substance X which will deposit when a solution containing 50g of X in 100g of water initially at 80oC is cooled to a temperature of 30oC (1mk)
    1. The diagram below shows a set – up that was used to prepare oxygen gas and passing it over a burning candle. The experiment was allowed to run for some time.
      04 Chem p2q4
      1. Name liquid X (1mk)
      2. Suggest the PH of the solution in conical flask K. (1mk)
      3. Write an equation for the reaction taking place in the conical flask M. (1mk)
    2. During the extraction of sodium metal from sodium chloride in the Down’s cell, calcium chloride is added
      1. Explain why it is necessary to add Calcium chloride (1mk)
      2. Explain why sodium metal is not used in making the overhead electric cables yet it is a conductor of electricity (1mk)
      1. Describe a simple chemical test that can be used to distinguish carbon (IV) oxide and Carbon(II) oxide gases. (1mk)
      2. Give one use of carbon (II) Oxide (1mk)
    4. A form two student inverted a gas jar full of carbon (IV) oxide over water and sodium hydroxide solution separately as shown below
      04 Chem p2q4d
      Explain the observations made. (2mks)
    1. Study the diagram below and use it to answer the questions that follow.
      04 Chem p2q5a
      1. Name liquids A and B (2 mks)
      2. Suggest a suitable reagent that can be used as solid D (1mk)
      3. State the role of Solid D (1mk)
      4. Write a balanced chemical equation for the reaction in the conical flask (1mk)
      5. Explain why solid C collects further away from the heated aluminium metals. (1mk)
      6. In the combustion tube above, 0.675g of aluminium metal reacted completely with 1800cm3 of chlorine gas at room temperature. Determine the molecular formula of Solid C, given that its relative formula mass is 267 ( Al= 27.0, Cl= 35.5 molar gas volume at r.t.p = 24.0 litres) (3mks)
    2. The reaction between hot concentrated sodium hydroxide and chlorine gas produces Sodium Chlorate (V) as one of the products
      1. Write the equation for the reaction. (1mk)
      2. Give one use of sodium chlorate.(V) (1mk)
      3. Explain the difference between bleaching by chlorine and bleaching by sulphuric (IV)oxide gases. (2mks)
    1. Study the diagram below that is used to prepare a gas Q.
      04 Chem p2q6a
      1. What component of air is eliminated in wash bottle labelled R? ( 1 mark )
        1. Write the reaction equation for the reaction that eliminates the component of air in a(i) above. (1 mark)
        2. What component of air is removed in hard glass tube labelled P? ( 1 mark )
        3. Identify gas Q. (1 mark )
    2. In an experiment 1.54g of nitrogen reacted with 3.53g of oxygen to form a compound. N = 14, O = 16
      1. Calculate the moles of nitrogen and oxygen that reacted. (2 marks )
      2. Determine the simplest formula of the compound formed between nitrogen and oxygen. (2 marks )
      3. Commend on the melting and boiling points of the compound in B(ii) above, explain. (2 marks)
  7. In the preparation of Copper carbonate, copper was burnt in air and the product collected. Dilute sulphuric acid was added and the mixture filtered and cooled. Sodium carbonate was added to the filtrate and the content filtered. The residue was washed and dried to give a white powder.
    1. Give the chemical name of the product formed when magnesium burns in air (1mk)
    2. Write a chemical equation for the formation of product. (1mk)
      1. Name filtrate collected after sodium carbonate was added (1mk)
      2. Name the white powder. (1mk)
    4. Write chemical equation for the reaction between product in (a) and acid. (1mk)
    5. Write an ionic equation to show the formation of the white powder (1mk)
    6. Write an equation to show what happened when white powder is strongly heated. (1mk)
    7. Using a diagram, describe how a salt can be obtained from the filtrate in c(i) above (3mks)

Marking Scheme

      1. K √1mk
      2. J or C √1mk
      3. Group 4 , period i.e. below S in the grid
      4. J and U are in the same period and across the period the nuclear charge increases hence nuclear charge of U is greater than that of J hence it pulls the outermost electron more strongly reducing the radius.
      5. Y – is better conductor because it has more delocalized electrons. OR Y- has 3 delocalized electrons while A how one delocalized electron.
      6. The B.p of the elements increases √1mk down the group. This is because the intermolecular forces of attraction increase √1mk down the group with increase in the size of the molecules.
      1. V and G√1mk because they are in the same group or loses 2 electrons / some number of electrons in the outer energy levels.
      2. X, √½mk because its ionic radius is bigger tendency to donate its electron is high. √½mk
      3. E, √½mk because its ionic radius is bigger than atomic radius so its tendency to donate its electron is high. √½mk
    1. Fractional distillation √1mk
      1. Cracking – is the braking of long-chain alkane molecules into shorter alkanes and an alkene by
        heating or use of catalyst. √1mk
        • Heat or temperature 400oC – 700oC Any two correct for√1mk each
        • Silica /SiO2 or Catalyst – silica /SiO2
        • Aluminium oxide Al2O3
      3. C10H22(l) → C5H12 + C5H10(g) √1mk
        04 Chem p2qa2iv
      5. Shake a sample with;
        Bromine C5H12 does not decolourise, C5H10 decolourise OR. – Acidified Potassium
        chromate (VI) with C5H12 the orange colour does not change but with C5H10 the orange
        colour changes to green OR Burn a sample of C5H12 burns with a non-luminous flame; while C5H10 burns with luminous
      1. Soapy √1mk Detergent √1mk
      2. Soapless detergent √1mk because it is non-biodegradable √1mk hence pollutes the Environment.
      1. Name – Aluminium hydroxide √½
        Formula: Al(OH)3(s) √½ (1mk)
      2. Name: Sodium aluminate / tetrahydroxo aluminate √1
        Formular: NaAl(OH)4(aq) /[Al(OH)4]-(aq) √1 (2mks)
    2. Amphoterism
    3. Al(OH)3(s) + OH-(aq)→ [Al(OH)4]-(aq) (1mk)
        04 Chem p2qa3di        
        1. 33/100g of H2O (must be on the graph)
        2. 25°C √1
        3. Solubility of X at 30oC = 19g/100g of water mass of crystals deposited 50-19 = 31g √½ (1mk)
      1.  Water
      2. 6.5; √1 presence of Carbonic acid
        i.e CO2 + H2O → H2CO3
      3. 2 Na2O2(s) + 2H2O(l) →4NaOH(aq) + 2O2(s) √1
      1. to lower the melting point of sodium chloride √1
      2. sodium react with air and water vigorously/sodium would react with moist air √1
      1. If CO2 is bubbled in lime water for a few minutes white ppt. is formed. No white ppt. forms when CO is bubbled into lime water.
      2. Extraction of metals √1
    4. CO2 is highly soluble√½ in sodium hydroxide to form Na2CO3 √½soluble in water to form Carbonic acid. √ (2mks)
      1. A – Concentrated hydrochloric acid√1
        B – water √ 1mk
      2. Calcium oxide / CaO√ (1mk)
      3. To absorb unreacted /excess chlorine √
      4. 2KMnO4(s) + 16HCl(aq) →2KCl(aq) + 2MnCl(aq) + 8H2O(l) + 5Cl2(g) √1
      5. Solid C sublimes √ hence collects on a cooler place away fromheating.
         Elements  present  Al  Cl
        Mass/ volume
        R.A.M/ M.G.V   
        No. of moles  0.675/27 = 0.0025 1800/24100 = 0.075
        Mole ratio 0.025/0.025=1 0.075/0.025 = 3
          ED = AlCl3  
        (AlCl3)n = 267
        (27 + 35.5 x 3)n = 267
        n = 267/ 133.5 = 2
        M.F = (AlCl3)= Al2Cl6
      1. 6NaOH(aq) + 3Cl2(g) → NaClO3(aq) + 5NaCl(aq) + 3H2O(l)
      2. Bleaching agent in paper pulp√1 // Used as herbicides √1
    3. Sulphur (IV) oxide bleaches by reduction√½ and removal of oxygen from the dye hence temporary √½ while chlorine bleaches by oxidation√½/adding oxygen to the dye hence permanent. √½
      1. Carbon (IV) oxide or CO2 or
        Carbon (IV) oxide (CO2) √1 (Any)
        1. KOH(aq) + CO2(g) → KHCO3(aq) √1
          Wrong balanced = 0
          State symbols wrong or missing ½ mark
        2. Oxygen gas or O2(g) or oxygen (O2) gas √1
        3. Nitrogen gas or N2(g) or nitrogen (N2) gas. √1
      1. Moles of nitrogen =     1.54       √ ½ = 0.11 √ ½
        Moles of oxygen =        3.53    √ ½ = 0.22 √ ½
           N  O
        Mole ratio  0.11/0.11= 1  0.22/0.11= 2
        Simplest formular  NO2  
      3. Compound has low melting and boiling points √1 because it has a weak Van der wall forces √1
    1. copper oxide / CuO √1mk
    2. CuSO4(aq) + Na2CO3(aq) → CuCO3(s) + Na2SO4(aq) √1mk
      1. Sodium sulphate / Na2SO4 √1mk
      2. Copper carbonate √1mk
    4. CuO(s) + H2SO4(aq) → CuSO4(aq) + H2O(l) √1
    5. Cu2+(aq) + CO32-(aq) → CuCO3(s) √1mk5
    6. CuCO3(s)→  CuO(s) + CO2(g) √1mk
    7. Filtrate √ ½
      Beaker √ ½
      Water bath√ ½
      Tripond stand √ ½
      Workability √1mk
      04 Chem p2qa7g
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