P6 Molecules And Matter

Question 1

What is the specific latent heat of a substance?

Answer 1

The amount of energy required to change the state of 1kg of a substance with no change in temperature

Question 2

Explain in terms of particles, how evaporation causes the cooling of water (4)

Answer 2

• Fastest particles have enough energy (Ek) to escape off of the surface of the water. The mean energy of the remaining particles decreases, and a lower mean energy = lower temperature