Question

Comment on each of the following statements :- a) Evaporation causes cooling. b) Sugar Crystals dissolve faster in hot water than cold water. c) Ice is solid at 0 degree C, while water is liquid at room temperature.

Answer 1

Dear Student ,

1. Evaporation creates cooling as the particles at the surface of the liquid gain energy from the
   surroundings and change into vapour, thereby producing a cooling effect.
2. Ice is solid at 0°C because it has a certain volume and specific shape due to strong intermolecular forces. Water is liquid at room temperature because it has only definite volume and no particular shape due to weak intermolecular forces of attraction.
3. Sugar crystals dissolve easily in hot water than cold water because hot water molecules have more kinetic energy. Due to this reason, they strike faster on the particles of sugar than cold water molecules. As a result, hot water will dissolve sugar crystals faster than cold water.

Regards