What do you observe in the following cases?

(a) Lead nitrate is heated.

(b) Silver chloride is exposed to sunlight.

(c) Hydrogen peroxide is exposed to sunlight

(d) H₂S gas is passed through copper sulphate solution

(e) Barium chloride is added to sodium sulphate solution.

(f) Water is added to quick lime

(g) Sodium chloride solution is added to silver nitrate solution.

Discuss the factors that affect a chemical change.

State the main characteristics of chemical reactions. Give at least one example in each case.