Define the following terms:

(a) Chemical change

(b) Chemical bond

(c) Effervescence

(d) Precipitate

Give an example of a reaction where the following are involved:

(a) Heat

(b) Light

(c) Electricity

(d) Close contact

(e) Solution

(f) Pressure

(g) Catalyst

Give an example of each of the following chemical changes.

(a) A photochemical reaction involving 1. silver salt 2. water

(b) A reaction involving 1. blue solution 2. formation of a dirty green precipitate

(c) Two gases combine to form a white solid.

(d) Two solids combine to form a liquid.

(e) A reaction where color change is noticed.

Write the chemical reaction where the following changes are observed.

(a) Gas is evolved

(b) Colour change is noticed

(c) Precipitate is formed

(d) Physical state of reactants is changed