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SHC and SLH
Fourth form revision stack
Question | Answer |
---|---|
What is specific heat capacity? | The energy needed to change the temperature of 1kg of something by 1 degree without a change of state. |
What is specific latent heat? | The energy needed for 1 kg of substance to change state without a change in temperature. |
Units of specific heat capacity? | Joules per kg per degree Celsius. |
Units of specific latent heat? | Joules per kg |
What is another word for melting? | Fusion |
What does condensation mean? | Change from gas (or vapour) to liquid. |
What does sublimate mean? | Change from solid to gas. |
Name two ways liquids change to gases. | Boil and evaporate |
Why does a boiling liquid have bubbles but an evaporating one does not? | Evaporation just from surface, boiling all through liquid. |
Name three ways to increase rate of evaporation of some water. | Larger area, breeze, higher temperature. |
What happens to KE of molecules when temperature rises? | The KE increases. |
Why do molecules need energy for a liquid to vapourise? | Bonds between molecules in the liquid need to be broken. |
What does a horizontal section of a cooling curve show? | steady temperature, probably change of state |
What is Melting Point? | Temperature when solid turns to liquid. |
What is Freezing Point? | Temperature when liquid turns to solid. |
Specific Latent Heat of fusion of a metal is 200 kJ per kg. How much energy is given out when 3 kg solidifies at 150 degC? | 600kilojoules (600 000 joules) |
Specific Heat Capacity of a liquid is 3000 J per kg per deg C. How much heat energy is needed to warm 2 kg by 3 deg? | 18 000 joules (18 kJ) |
At any temperature, a liquid has a mixture of fast and slow molecules. Which ones are most likely to escape by evaporation? | Fast ones |
If the average KE of the molecules in a liquid goes down, what happens to the temperature? | It falls, liquid cools. |
What does KE stand for? | Kinetic Energy |