Give an example of each of the following chemical changes.

(a) A reaction involving

(i) change of state

(ii) formation of a precipitate

(b) An exothermic and an endothermic reaction involving carbon as one of the reactants.

(c) A reaction where colour change is noticed.

What is a chemical change? Give two examples of a chemical change?

Why is energy involved in a chemical change?

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