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Form 3 Chemistry Paper 3 End of Term 2 Exams 2021

Class: Form 3

Subject: Chemistry

Level: High School

Exam Category: Form 3 End Term 2 Exams

Document Type: Pdf

Views: 927 Downloads: 16

Exam Summary

CHEMISTRY
Paper 3
(Practical)
TERM TWO 2021
FORM THREE

1. You are provided with;
- Solution C which is solution of dibasic acid #(COOH)_2 XH_2 O# containing 10.08g per litre of solution.
- Solution D which is 0.2M solution of sodium hydroxide.
You are required to determine the value of X in the formula #(COOH)_2XH_2O#
(H= 1, C = 12, O = 16)

Procedure
- Fill the burette to the mark with solution C.
- Pipette 25.0#cm^3# of solution D into a clean conical flask
- Add two drops of phenolphthalein indicator and titrate with solution C.
- Repeat the titration to obtain consistent results and record your results in table 1 below. 4mks

a) Calculate the average volume of solution C used. (1mark)

b) Calculate the number of moles of D used. (2marks)

c) Calculate the number of moles of C used given that the reacting ratio of acid to base is 1:2 (2marks)

d) Calculate the concentration of acid solution C in moles per litre. (2marks)

e) Calculate the relative formula mass of the acid #(COOH)_2 X H_2O#. (2marks)
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f) Hence, determine the value of X in #(COOH)_2 X H_2O#. (2marks)
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2. You are required to determine the enthalpy of displacement of #Cu^(2+) (aq)# by Zinc.
Procedure
i) Wrap the plastic beaker that has been provided with a tissue paper.
ii) Place 50#cm^3# of 0.2M Copper (II) Sulphate solution in the beaker. Dip the thermometer in the solution and note the steady temperature of the solution.
iii) Carefully transfer all the 1.0g of Zinc powder provided into the plastic beaker and stir carefully with the thermometer.
iv) Record the highest temperature that the solution attain.
Record the results in the Table II below.

(2marks)
Specific heat capacity = #4.2kJKg^(-1)k^(-1#
Density of the solution = 1g/#cm^3#
a) Calculate the number of moles of #Cu^(2+)# ions that are in 50#cm^3# of the solution. (2marks)

b) Calculate the amount of heat liberated in the reaction. (2marks)

c) Determine the enthalpy of displacement of Copper. (2marks)

d) Explain why excess Zinc powder was added into the beaker. (1mark)

e) Write the ionic equation for the reaction that takes place. Indicate the enthalpy change for the reaction. (2marks)

3. You have been provided with solid Q. Perform the tests below and identify ions present in the sample.
i) Put all the solid Q in a boiling tube and then add 8#cm^3# of distilled water a little at a time while shaking. Divide the solution formed into five portions in test tubes.

ii) To the first portion add dilute sodium hydroxide drop wise until in excess.

iii) To the second portion add ammonia solution dropwise until in excess.

Form 3 Chemistry Paper 3 End of Term 2 Exams 2021

Exam Summary

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