3. Explain the following- a) Gases exert pressure on the walls of the container b) Water is liquid at room temperature c) Evaporation causes cooling
Answers
a)The pressure exerted by a gas is due to the random motion of particles in the gas. Gases have weak intermolecular forces and the particles in continuous random motion and these particles collide with the walls of the container. These collisions with the walls of the container exerts pressure on the gas.
b)At room temperature (25°C), water is a liquid because it has the following characteristics of liquid: At room temperature, water has no shape but has a fixed volume i.e., it occupies the shape of the container in which it is kept. At room temperature, water flows easily
c)During evaporation particles of the liquid gain energy from the surroundings to overcome the force of attraction between them. As a result loss of heat energy occurs in the surroundings that is why evaporation causes cooling .
Answer:
itxuf urcgxyurxurc fu ts ufcydc ig ig hin