Specific and Latent Heat Flashcards
what is specific heat capacity
The specific heat capacity of a substance is the amount of heat required to raise the temperature of a 1kg substance by 1°C. This depends on:
Mass, specific heat capacity and (the change in) temperature
Conservation of energy
An isolated system is one in which no energy or matter can enter or leave. Therefore, within an isolated system, the total amount of energy remains constant. Energy can be converted from one form to another. Energy can be transferred from place to place. But the total energy within the isolated system remains constant.
state changes and latent heat and power
A pure solid starts to change state to a liquid at its melting point. A pure liquid starts to change state to a gas at its boiling point. Both processes, melting (fusion) and vaporisation require energy input. Energy removal causes gases to undergo condensation and liquid, solidification.
lateent heat
Quite large amounts of heat are necessary to cause a change of state and all this, without a change in temperature. This heat is referred to as latent heat (hidden heat). The energy added during a state change is called latent heat.
formula for specific heat
Q=mcT
specific heat of fusion
The specific latent heat of fusion is the amount of heat required to change 1kg of a substance from solid to liquid (or vice versa) without any change in temperature. When a solid is heated to its melting point, its particles gain energy and are able to partly overcome the forces of attraction between them.
specific heat of vaporisation
The specific latent heat of vaporisation is the amount of heat required to change 1kg of a substance from a liquid to gas (or vice versa) without any change in temperature. When the liquid is heated to its boiling point, its particles gain enough energy to completely overpower the intermolecular forces of attraction.
On warm days people often use fans to help them keep cool even though the fans themselves don’t cool the air. Explain why you feel cool.
The sensation of feeling cool while using a fan is because of the process of evaporative cooling. When air blows across our skin. It increases the evaporation of moisture from our skin which helps dissipate heat and make us feel cooler.
