specific latent heat

• energy needed to change state is latent heat
• when a substance boils/melts, energy is being put in increasing internal energy and temperature but energy is used for breaking bonds (flat lines on graph)
• when a substance is freezing/condensing, bonds are forming between particles which releases energy decreasing internal energy but temp does not go down until change in state(flat parts show energy transfer)
• specific latent heat is energy needed to change the state of a 1kg mass of a substance without changing its temperature
• for cooling, specific latent heat is energy released by a change in state
• specific latent heat of fusion is the amount of energy needed to change the state of 1kg of a substance from solid to liquid
• specific latent heat of vaporisation is the amount of energy needed to change the state of 1kg of a substance from liquid to gas
• energy= mass x specific latent heat