Specific Latent Heat Flashcards
What is specific latent heat?
Latent heat means hidden heat
It tells us how much energy is needed to change its state of matter
What is specific latent heat of fusion - J/kg?
Solid to Liquid/Liquid to Solid
A solid substance turns into a liquid at its melting point
It’s temperature stays constant until all solid is melted
The energy required to change the state of 1kg from solid to liquid at its melting point
It is the energy needed for the particles to break free from each other
The unit is joules per kilogram - J/kg
Energy➗mass
What is specific latent heat of vaporisation - J/kg?
Liquid to Gas/Gas to Liquid
Energy needed to change 1kg of substance from Liquid to gas at its boiling point
A liquid substance turns into vapour at its boiling point when it’s heated
Energy supplied is latent heat of vaporisation
The energy needed for particles to break away from their neighbouring particles
If the gas cools it will condense at the same temperature as its boiling point
Latent heat is transferred to the surroundings as the substance condenses into a liquid and particles form new bonds
What is the equation for specific latent heat?
Energy = mass x vaporisation E = m x Lv Energy = mass x fusion E = m x Lf
What do we use to measure specific latent heat of ice?
A low voltage heater to melt the ice or to boil the water
What happens to temperature in the changing state of matter?
Temperature rises to melting point and boiling point but stays the same at melting point and boiling point until all solid is melted or liquid is vaporised
Why does a scald (burn) from steam at 100c worse than a scald from water at 100c?
Steam has more energy because it took extra energy to convert water to steam and it’s because the particles are free
Specific latent heat equation
Energy - makes sure it is energy x time
Mass - can be mass evaporated
