THE PRESIDENT’S OFFICE
REGIONAL ADMINISTRATION AND LOCAL GOVERNMENTS
CHEMISTRY FORM JOINT EXAMINATION ASSEMENT 2021.
TIME: 3:00 HOURS STUDENT NAMES:
1: This paper consists of eight (8) pages with section A, B and C with a total of fourteen (14) questions
2: Answer all questions in both sections A and B and ONLY ONE QUESTION FROM SECTION C
3: All working must be in blue or black ink except for drawings which must be in pencil.
4: Scientific calculator can be allowed in the examination room.
5: The following constant may be used.
- ATOMIC MASSES : H = 1 C = 12 O = 16 Ca = 40 Mn = 55
- GRAM MOLECULAR VOLUME = 22.4dm3 AT S.T.P
- 1 FARADAY = 96500 COULOMBS
1 LITRE = 1dm3 = 1000cm3
FOR EXAMINER’S USE ONLY
SECTION A (15 MARKS)
1. Choose the most correct answer from among multiple alternatives and write the answer in the answer booklet you have provided.
i. Which of the following pairs of compounds will give oxides when heated?
- Cu (NO3) and Na2 CO3
- Zn (NO3)2 AND k2 CO3
- Ca (NO3)2 and Cu (NO3)2
Pb (NO3)2 and AgNO3
ii. Sodium hydroxide was added to three different test tubes, X,Y and Z. blue, green and reddish-brown precipitates were formed, respectively. The metal ions present in test tubes X,Y and Z in the respective are likely to be:
- Ca2+, Pb2+ and Al3+
- Cu2+, Fe2+ and Fe3+
- Ag+, Pb2+ and Mg2+
Pb2+, Mg2+ and Ca3+
iii. Group I elements burn in oxygen to form ______
- Non-metal oxides
- Metal oxides
iv. Which of the following is not a physical way of separating a mixture?
- Paper chromatography
- Simple distillation
V. What number of Faradays of electricity are required to deposit 4 g of calcium from molten calcium chloride?
vi. What type of fire is associated with electrical equipment?
- Class E
- Class F
- Class B
- Class C
vii. A nitrogen molecule forms covalent bonds. How many electrons are shared between nitrogen atoms?
- 2 electrons
- 3 electrons
- 6 electrons
- 4 electrons
viii. The reaction that can proceed on either direction by changing the condition that governs the reaction is called ______
- Endothermic reaction
- Displacement reaction
- Reversible reaction
- Exothermic reaction
ix. Which of the following are primary macronutrients?
- Phosphorus, calcium and potassium.
- Potassium, calcium and nitrogen
- Nitrogen, phosphorus and potassium
Magnesium, calcium and nitrogen.
x. The formulae below represent some chemical substances. Which formula represents a substance that does not contribute to global warming?
2. Match list A with their corresponding letter in list B (5MARKS)
SECTION B (70 MARKS)
3 (a) What volume of ethyne measured at S.T.P would be evolved from 32g of 50% pure calcium dicarbide?
(b) Describe how stoichiometry is important in medicine.
4. With a well balanced chemical equation explain what will happen for each of the following observation?
(a) Sodium metal is placed in cold water.
(b) A piece of cobalt paper is exposed in air for a while.
(c) Silver nitrate is kept in a colored bottle.
(d) A heated copper oxide is passed over hydrogen gas.
(e) A reaction between lead nitrate with dilute sulphuric acid stops as soon as starts.
(f) Hydrogen sulphide gas is placed in a jar full of sulphur dioxide gas.
(g) A blue litmus paper in ammonia gas.
5. (a) What are four constituents of universal indicator?
(b) Two different solutions P and Q into different test tubes were tested using solutions X and Y. On reaction with solution X solution P turns purple and colorless on reaction with solution Q. But on reaction with solution Y solution P turns yellow and finally pink on reaction with solution Q.
- Identify solutions P and Q.
- State one example of solution P and Q
Identify solutions X and Y.
6 (a) Permanent hardness of water is the type of water that cannot be removed by boiling. Explain
(b) Is water a mixture of hydrogen and oxygen? Give four reasons to support your answer.
7(a Copper obtained during extraction process is known as a Blister copper which is impure one. It is purified through electrolysis is to obtain pure copper.
- Name the electrolyte used to purify impure copper
- Name the nature of electrode used.
(b) Consider the electroplating of a spoon using a silver metal
- Name the type of electrolyte that can be used
- At which electrode a spoon will be placed?
- Draw a well labeled diagram to represent this information process.
- Write down the ionic equations at each electrode.
8(a) Describe four human activities that cause air pollutants.
(b) The prevention of using plastic bags plays a great role to our environment. Write three advantages of stopping the use of plastic bags to the environment.
9. Study the fgure given below then answer the questions that fol
- Label subastances A, B and C
- Write a well banaced chemical equation for the preparation of gas C
- State the role of B and concentrated sulphuric acid.
- What will happen when green leaves are placed in a jar of gas C? Explain
11. Sulphuric acid is prepared by contact process. During the catalytic conversion of sulphur dioxide to sulphur trioxide equilibrium is established.
(a) Show the catalytic conversion process with a well-balanced chemical equation.
(b) State the role of a catalyst used in this process.
(c) Show how temperature and pressure would increase the production of sulphur trioxide.
(d) Explain why is it unfavorable to work with very low temperature and high pressure in this process?
12(a) Determine the empirical formula of a substance that has the following composition by mass:
49.5% manganese and 50.5% oxygen.
(b) An isotope of neon has a mass number of 21 and an atomic number of 10
- Write its nuclide notation
- How many neutrons does it have?
- How many electrons does it have?
- Explain why an atom is electrically neutral
SECTION C (15 MARKS)
13. On reaction with water gas R produces solution S (C2H5OH). When R reacted with oxygen in the presence of potassium permanganate produces solution T. On reaction with U solution T produces substance solution V with liquid W. When solution V reacted with alkaline solution X gave gas Y which produces tetrachloro methane on reaction with chlorine gas in the presence of sunlight.
(a) Identify substance R, T, U, V, X and Y
(b) Show all chemical reactions involved in each step.
14. With a critical reason explain what will happen for each of the following phenomenon.
(a) Magnesium sulphate solution is added into a test tube contains sodium carbonate solution.
(b) Potassium iodide solution mixed with lead carbonate solution.
(c) Manganese (iv) oxide solid was added in a solution of sodium chloride then heated gently.
(d) Barium nitrate solution together with dilute nitric acid was added into a lead sulphate solution.
(e) A concentrated sulphuric acid was added in a mixture of ferrous sulphate with copper nitrate solution.