Question

Question 11
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
f. Freezing of water
g. Burning of a candle

Answer 1

A chemical change is usually an irreversible reaction involving the rearrangement of the atoms of one or more substances. The change occurs in the chemical properties or composition, resulting in the formation of at least one new substance. Growth of a plant, rusting of iron, cooking of food, digestion of food, and burning of a candle are chemical changes because the chemical composition of the substance changes.