Question

Classify the following into physical and chemical changes.
1) Digestion of food
i) Mixing of Iron filings and sand
11) Burning of a candle.
1) Freezing of water.
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Answer 1

Digestion of food is a chemical change, as there are chemicals in the digestive tract that break down the food.

Mixing of iron filings and sand is a physical change, as they just mix with each other without the need of a chemical reaction.

Burning of a candle is also a physical change, as the flame causes the wax to melt down.

Freezing of water is also a physical change, as liquid water changes into solid ice without the need of a chemical reaction.

Answer 2

Among these Rusting of iron, cooking of food, Burning of a candle are chemical changes.