Which of the following are chemical changes?

(a) Growth of a plant

(b) Rusting of iron

(c) Mixing of iron filings and sand

(d) Cooking of food

(e) Digestion of food

(j) Freezing of water

(g) Burning of a candle

Growth of a plant, Rusting of iron, Cooking of food, Digestion of food and Burning of a candle are chemical changes.

Chemical change brings change in the chemical properties of matter and a new substances is formed. A chemical change is also called a chemical reaction. All of the above changes have resulted in the formation of new substances as a result of chemical reactions.