Phase Changes and Latent Heat worksheet

Worksheet 9- Section 10.4

Phase Changes and Latent Heat

1. Why is the evaporation of sweat from the skin a cooling process?

2. What is latent heat, and how does it affect the temperature of a substance?

3. How much thermal energy must be removed from 0.96 kg of water at 0 °C to make ice cubes at 0 °C? ( Latent heat of fusion of water = 335000 J/ kg)

4. A portion of the vapor-pressure curve for water is shown in figure 10.28 above. Referring to the figure, estimate the pressure (in kPa) required for water to boil at 30 °C.

5. Using the vapor-pressure curve for water is shown in figure 10.28 above. Estimate the temperature at which water boils when the pressure is 1.5 kPa.