Question
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
✓
Answer
Physical changes in burning candle On heating, candle's wax melts. Since, it can be turned into solid wax again on cooling. Hence, it is a physical change.
Chemical changes in burning candle The wax near to flame burns and gives new substances like carbon dioxide, carbon soot, water vapours, heat and light. Hence, it is a chemical change.
Cooking of food, boiling of eggs are examples of both physical and chemical changes. In both cases, the physical appearance of the substances change and new substances are formed together.
Chemical changes in burning candle The wax near to flame burns and gives new substances like carbon dioxide, carbon soot, water vapours, heat and light. Hence, it is a chemical change.
Cooking of food, boiling of eggs are examples of both physical and chemical changes. In both cases, the physical appearance of the substances change and new substances are formed together.
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