unit 5: heat specific heat capacity and latent heat
TRANSCRIPT
Unit 5: Heat
SPECIFIC HEAT CAPACITY AND LATENT HEAT
SPECIFIC HEAT CAPACITY (C)
• The quantity of heat required to raise the temperature of a unit of mass by a unit change in temperature
EXAMPLE
• When 4.0 kg of water is cooled from 40oC to 5oC. How much heat energy is lost?
SOLUTION
ASSIGNMENT
• Specific heat practice problems
• Lab: specific heat capacity in liquids
SPECIFIC LATENT HEAT
• Is the quantity of heat energy required to change the state of a unit of mass of substance
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)
SOLUTION
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)
SOLUTION
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
• Do practice problems
• Assignment- latent heat problems