Question

Which of the following are chemical changes?
$\left(a\right)$ Growth of a plant
$\left(b\right)$ Rusting of Iron
$\left(c\right)$ Mixing of iron fillings and sand
$\left(d\right)$ Cooking of food
$\left(e\right)$ Digestion of food
$\left(f\right)$ Freezing of water
$\left(g\right)$ Burning of a candle.

Answer 1

A chemical change is a change that brings a change in the chemical properties of matter and a new substance is formed.

Examples of chemical changes from the given list of changes are:
Rusting of iron, Cooking of food, Digestion of food, and Burning of a candle.