Define a chemical reaction. Which observation help you to determine whether a chemical reaction has taken place?

3

(a)

Define the term decomposition reaction. Give one example each of thermal decomposition and electrolytic decomposition.

3

(a)

Write the chemical equation of the reaction with an example each in which the following change has taken place:
(i) Change in colour
(ii)Change in temperature
(iii) Formation of precipitate.

3

(a)

A sanitary worker uses a white chemical having strong smell of chlorine gas to disinfect the water tank.
(i) Identify the chemical compound, write its chemical formula.
(ii) Give chemical equation for its preparation.
(iii) Write its two uses other than disinfection.

3

(a)

Explain the action of dilute hydrochloric acid on the following with chemical equation:
(i) magnesium ribbon
(ii) sodium hydroxide
(iii) crushed egg shells

3

(a)

After drinking an excess of cold drink, a person suffered from acidity. Explain

3

(a)

Name a major ore from which iron is extracted. Write chemical equations for the reactions that take place in the blast furnace for the extraction of iron from this ore.

3

(a)

State five points of differences between ionic compound and covalent compound.

3

(a)

List three properties of sodium in which it differs from the general physical properties of most metals.

3

(a)

You are given samples of three metals: Sodium, magnesium and copper. Suggest any two activities to arrange them in order to their decreasing reactivity

3

(a)

Draw a diagram of human brain and label on it the following of its parts:
(i) Cerebrum
(ii) Meninges
(iii) Medulla Oblongata
(iv) Cerebellum

3

(a)

How do neurons transmit information?

3

(a)

A touch bulb is rated 2.5 V and 750 mA. Calculate (i) its power, (ii) its resistance and (iii) the energy consumed if this bulb is lighted for four hours.

3

(a)

Distinguish between an electric motor and generator?

3

(a)

(a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity required to obtain useful energy with a windmill?
(c) Define the term 'nuclear fission'.

3

(a)