Some changes are given here. Write physical changes in the area marked 'A' and chemical changes in the area marked 'B'. Enter the changes which are both physical and chemical in the area marked 'C'. Process of burning a candle; Tearing of paper; Rusting; Curdling of milk; Ripening of fruits; Melting of ice; Folding of clothes; Burning of magnesium and Mixing baking soda with vinegar.
Area A (Physical changes): Tearing of paper, Melting of ice, Folding of clothes.
Area B (Chemical changes): Rusting, Curdling of milk, Ripening of fruits, Burning of magnesium, Mixing baking soda with vinegar.
Area C (Both physical and chemical changes): Process of burning a candle.
The burning candle involves both physical changes (melting of wax, solidification, evaporation) and chemical changes (burning of wax vapour to produce flame and new substances).
Explanation
The chapter clearly categorizes various changes. Physical changes like tearing, melting, and folding only alter physical properties without forming new substances. Chemical changes like rusting, curdling, ripening, burning, and mixing baking soda with vinegar form new substances. The burning candle is specifically explained in Activity 5.7 as involving both types of changes - melting and evaporation of wax are physical, while burning of vapour is chemical.
Solution Steps
Physical changes like tearing, melting, and folding only alter physical properties without forming new substances
Chemical changes like rusting, curdling, ripening, burning, and mixing baking soda with vinegar form new substances
The burning candle involves both types of changes - melting and evaporation of wax are physical, while burning of vapour is chemical