Specific Heat Capacity and Latent Heat

1. Specific Heat Capacity and Latent Heat Unit 5: Heat

2. Specific Heat Capacity (c) • The quantity of heat required to raise the temperature of a unit of mass by a unit change in temperature

3. example • When 4.0 kg of water is cooled from 40oC to 5oC. How much heat energy is lost?

4. solution

5. assignment • Specific heat practice problems • Lab: specific heat capacity in liquids

6. Specific Latent Heat • Is the quantity of heat energy required to change the state of a unit of mass of substance

7. Specific latent heat of fusion • The quantity of heat energy released when 1 kg of substance solidifies without changing temperature • Ex. how much heat energy is needed to change 2.0 kg of ice @ 0oC to water @ 0oC (lfus= 3.3x103 J/kg)

8. Solution

9. Specific latent heat of vaporization- • is the quantity of heat energy needed to vaporize 1 kg of substance without changing its temperature • Ex. how much heat energy is needed to change 0.50 kg of water @ 100oc to steam @ 100oc? (lvap= 2.3x106 J/kg)

10. solution

11. Latent Heat applications • Picnic coolers- ice in a cooler will absorb some heat from food keeping it @ a cool temperature • Preventing frost damage-gardeners turn sprinklers on crops, because when the water hits the plants and starts to freeze it will actually release some heat to plant • Cooling off when wet- when you get out of a shower the water will use your body heat to vaporize (if you don’t dry off) and since heat has left your body, you will feel cooler

12. Do practice problems • Assignment- latent heat problems