Chans
(80 MARKS)
Answer only four (4) question from this section.
2
Credit will be given for clarity of expression and orderly presentation of material.
1. a. i) List three sources of organic matter in the
soil (3 marks)
ii) State two ways in which organic matter is
important to the soil (2 marks)
b. i) State three differences between esterification
reaction and neutralization reaction (3 marks)
ii) Write the structural formula of each of the
chemical compounds
a) Ethanoic acid
B) 2,2-dimethylbutane
Y) 3-methylpent-2-ene
c) 2-methylbutan-2-ol (4 marks)
c) i) Explain the term oxidation number of an atom
(2 marks)
ii) Determine the oxidation number of
Manganese(Mn) in potassium permanganate
(KMnO4) (2 marks)
d) i) Explain the term potential energy (2 marks)
ii) A body of mass 70kg is placed 20m above the
ground. Calculate its potential energy. (g=10.0m/s²)
(2 marks)
2. a. i) Explain the term ration as used in animal
production (2 marks)
ii) Give three reasons for feeding animals with a
balance diet. (3 marks)
b. i) State three processes involved in purifying
water to be supplied to a community (3 marks)
ii) What is the function of liquid ammonia in
refrigerators (2 marks)
c. i) What does the expression plastics are insulators
mean? (2 marks)
ii) A simple electrical circuit has a supply delivering
1.5V. If the current in the circuit is 0.5A. Calculate
the resistance. (2 marks)
d) Explain each of the following ecological terms:
i) Community
ii) population
iii) Ecosphere (6 marks)
3. a) Give four reasons why farm records are kept (
marks)
b) i) Name two organisms involved in the nitrogen
cycle (2 marks)
ii) State two processes in the nitrogen cycle that
contribute to the return of nitrogen to the
atmosphere. (2 marks)
c) i) What are radioisotopes (2 marks)
ii) Mention two problems associated with disposal
of nuclear waste (2 marks)
iii) Mention two electronic components in which
junction diodes are used (2 marks)