Chemistry Paper 3 Questions and Answers - Eagle II Joint 2021 Mock Exams

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  • Answer all questions.
  • You are NOT allowed to start working with the apparatus for the first 15 minutes of the 2 ¼ hours allowed for this paper. This time is to enable you to read the question paper and ensure that you have all the chemicals and apparatus that you may require.
  • Mathematical tables and electronic calculators may be used.

Question 1

You are provided with the following:

  1. Sodium hydroxide, solution B
  2. Hydrochloric  acid, solution A
  3. Sodium carbonate, solution Q prepared by dissolving 31.8 grams in one litre of solution.
    You are required to: 
    1. Standardize Hydrochloric acid, solution A using sodium carbonate, solution Q
    2. Determine the molar enthalpy of neutralization of the acid using sodium hydroxide, solution B.

Procedure I

Fill the burette with hydrochloric acid, solution A. Pipette 25 cm3 of sodium carbonate, solution Q and transfer into a clean conical flask. Add 3 drops of methyl orange indicator and titrate against Solution A from the burette.  Repeat the procedure two more times and fill table I below.

Table 1.
    I  II  II
 Final burette reading (cm3)      
 Initial burette reading (cm3)      
 Volume of solution A used (cm3)      
  1. Calculate the average volume of solution A used.                                                   (1mk)
  2. Calculate the concentration of sodium carbonate solution Q in moles per litre.        (1mk)
    (Na=23, O=16, C=12)
  3. Calculate the number of moles of sodium carbonate, solution Q in the 25 cm3 that reacted.  (1mk)
  4. Calculate the number of moles of Hydrochloric acid, solution A that reacted with the 25cm3 portion of solution Q.               (1mk)
  5. Calculate the concentration of Hydrochloric acid, solution A in moles per litre.       (1mk)

Procedure II 

Pipette 25cm3 of sodium hydroxide, solution B into a clean 100ml plastic beaker.
Measure the temperature of this solution and record it in the table II below. Fill the burette with hydrochloric acid solution A. Run 5cm3 portion of the acid from the burette into the 100 ml plastic beaker containing 25cm3 of solution B. Stir using the thermometer and record the highest temperature reached. Repeat the procedure by running 5cm3 portions to the solution in the beaker until the total volume of the acid added is 35cm3 (3marks)
 Volume of acid added(cm3)  0   5   10   15   20   25   30   35
 Temperature (°C) of solution                
  1. Plot the graph of temperature (Y- axis) against volume of hydrochloric acid added  (X-axis).   (3mks)
  2. From your graph;
    1. Determine the highest temperature rise ∆T                                                        (1mk)
    2. Determine the volume of acid used                                                                       (1mk)
  3. Calculate the heat change for the reaction.                                                                  (1mrk)
    (Take C = 4.2kJkg-1k-1, density of solution 1g/cm3)
  4. Calculate the number of moles of the acid in the volume that reacted.                        (1mrk)
  5. Calculate the molar enthalpy of neutralization for this reaction.                                (1mk)

Question 2

You are provided with solid D. Carry out the following tests and record your observations and inferences in the spaces provided.

  1. Place a half a spatula-full of solid D onto a boiling tube. Heat gently and then strongly. Test the gases produced using both moist red and blue litmus papers.
     Observations  Inferences 
     (2 marks) (2 marks)
  2. Transfer the remaining solid D to a clean boiling tube. Add 8 cm3 of distilled water and divide into 4 portions.
    1. To the first portion, add sodium hydroxide solution until in excess.
       Observations  Inferences 
       (1 mark) (1 mark)
    2. To the second portion, add ammonia solution until in excess.
       Observations  Inferences 
       (1 mark) (1 mark)
    3. To the third portion, add 3 drops of 2M hydrochloric acid.
       Observations  Inferences 
       (1 mark) (1 mark)
    4. To the last portion add 3 drops of barium nitrate. 
       Observations  Inferences 
       (1 mark) (1 mark)

Question 3

You are provided with solid P. Carry out the following tests and record your observations and inferences in the spaces provided. 

  1. Place about one-third of solid P on a clean metallic spatula and burn it in a non-luminous Bunsen burner flame.
     Observations  Inferences 
     (1 mark) (1 mark)
  2. Place the remaining amount of solid P in a boiling tube. Add about 10 cm3 of distilled water and shake. Use the mixture for tests (i), (ii), (iii) and (iv) below.
     Observations  Inferences 
     (½ mark) (½ mark)
    1. Using about 2cm3 of the mixture in a test-tube, determine the PH using universal indicator solution and pH chart.
       Observations  Inferences 
       (½ mark) (½ mark)
    2. To about 2cm3 of the solution, add 3 drops of acidified potassium manganate (VII) solution.
       Observations  Inferences 
       (½ mark) (1 mark)
    3. To about 2cm3 of the solution, add the clean magnesium ribbon provided.
       Observations  Inferences 
       (½ mark) (1 mark)
    4. To about 2cm3 of the solution, add all the sodium carbonate provided.
       Observations  Inferences 
       (½ mark)

      (½ mark)


Table 1

    I  II  II
 Final burette reading (cm3)      
 Initial burette reading (cm3)      
 Volume of solution A used (cm3)   a   b   c

CT = 1
OP =1
AC =1
PA =1
FA = 1

Marking points
Complete table (CT) ……..……….1mrk
The table should be completed.
Penalize the following errors if any occurs.

  • Arithmetic error in subtraction.
  • Values recorded beyond 50cm3
  • Inversion of table
  • Penalize ½ mk only on any one of these errors.

Decimal point (d.p)………………… 1mk
All values to be recorded to 1d.p or
All values to be recorded to 2dp second decimal value being 0 or 5 only
Award 0-mark if whole numbers used or 2dp are used.
Accuracy mark (A)……………………1mrk
Consider any one candidates’ titre if within ± 0.10cm3 of school value award 1mk.
If it is  ± 0.11 to 0.20 award ½ mk. If beyond 0.20 award 1mk
Averaging principle (A)………………….1mrk
Three titres to be averaged if within ±0.1cm3 to one another.
Two titres can only be arranged if they are consistent.
N/B- If a student averages two titres when three are consistent award 0mk.
Final answer (F. A)………………………1mrk
If averaged titre is within 0.0 to 0.10cm3 of S.V award 1mk
0.11 to 0.2cm3 of s.v award ½ mk
If beyond 0.20cm3 award 0mk.
Complete table (CT) = 1mk
Correct use of decimals(dp) = 1mk
Accuracy (AC) = 1mk
Averaging (PA) = 1mk
Final answer (FA) = 1mk)
N/B – school vale (SV) teacher to perform practical to obtain school value.


Procedure I

  1. a+ b + c =  correct answer
  2. Concentration of Na2CO3, Solution Q.
    R. F. M of Na2CO3 = (23x2) + 12 + (16x3) = 106
    42.4 g
    = 0.4M
  3. Moles of Na2CO3 in 25cm3 that reacted.
    0.4 x 25
    = 0.01moles.
  4. Moles of Hydrochloric acid that reacted with 25 cm3 of solution Q.
    Na2CO3 + 2HCl →2NaCl + CO2 + H2O
    Mole ratio of Na2CO3   :   HCl   is 1 : 2
    Moles of HCl =  0.01 x 2 = 0.02 moles
  5. Concentration of hydrochloric acid, solution A
    0.02 X 1000
       ans in a
    = correct answer

Procedure II


  1. Complete table 1 mk
  2. Accuracy to S.V. ½ mk
  3. Decimal ½ mk
  4. Trend. 1mk

Distributed as follows:

Complete table

  • All columns filled 1mk
  • Any 7 correctly filled ½mk
  • Otherwise penalize fully
Compare candidate’s initial temperature with S.V; if with 1units award ½ mk,  otherwise penalize fully. 
Use of decimals. Award ½ mkfor decimal consistency, otherwise penalize fully.   
Award 1mk for, increase in temperature andat least a drop.
  1. Graph
    Chem EJM PP3Ans 1a
    Labelling - ½ mk
    Scale - ½ mk
    Plotting - 1 mk
    Shape - 1 mk
    1. ∆T shown in graph - (½ mk )
      Correct answer from graph - (½ mk
      • Shown in graph (½ mk)
      • Correct reading (½ mk)
        N/B: Wrong lines on the graph earns no mark on b) (i) and (ii)but score on the subsequent questions when transferred correctly.
  3. ∆H   = MC∆T   = (25 + c(ii) x 4.2 x c (i) ✓½mk
                            Correct answer ✓½
  4. Moles   = ans in procedure I (e) x  ans in proc II b (ii) ✓½  =  correct ans✓½
  5. Molar heat = 1 x ans in (c). ✓½
                              ans. (d)
                       = Correct answer. ✓½
    Penalize ½mk for missing sign and also for wrong units

Question 2: Solid D

 Observations  Inferences 
 a)Colorless liquid formed at the upper cooler  parts of the boiling tube. √½
Moist blue litmus paper turns red√½
While red litmus paper remains red.√½
White residue. √½    
                                                                                    Max 2 mrks

Hydrated salt √1
Acidic gas produced/
SO32-,CO32-, SO42-HCO3-√1
 4 ions = 1mk
3 ions = ½ mk
Less than 3 = 0 mk
N/B: Hydrated tied to colorless liquid formed. 
Max 2mks
i) –White precipitate √½soluble in excess √½
Zn2+,  Al 3+,  Pb2+ present √1
3 ions = 1mk
2 ions = ½ mk
1 ion = 0mk
- Penalize ½ mk for every contradictory ion to a max of 1mk
ii) - White ppt√½
         - Insoluble in excess√½
 Al3+,  Pb2+ present √1
 iii) No white precipitate √½
      No effervescence/ bubbles√½ 
 Al3+ present √½
SO32- CO32- absent√½
 iv) – White precipitate,√1  SO42- present √1
Question 3
  1. Solid P
     Observations  Inferences 
    Burn with yellow sooty flame√1
    Yellow flame √½
    Unsaturated organic compound. √1
    –C = C– or – C  C–
    Rej   C = C or  C   C 
    - Penalize fully for any contradiction
     Observations  Inferences 
     Dissolve√½ forming a colorless solution
    Polar organic compound. √½
    Rej. Polar hydrocarbon 
       Observations  Inferences 
       pH= 4, 5 or 6√½
      Weakly acidic.√½
       Rej: weak acid
       Observations  Inferences 
      Purple color of H+/ KMnO4 changes to colorless. √½
      R-OH,  –C = C– or – C   C -√1
      2 Mentioned, ½ mks
      1 mentioned, 0 mk
      Penalize fully for any contradiction
       Observations  Inferences 
       Effervescence observed√½
      R-OH, RCOOH √1
      1 mentioned ½
       Observations  Inferences 
       Effervescence observed.√½ RCOOH√½
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