specific latent heat

Question 1

when a substance is melting or boiling

Answer 1

you’re putting in energy so increasing internal energy but the energy is used to break bonds rather than raising temperature

flat spots on heating graph = energy transferred by heating = not to change temp

Question 2

when a substance is condensing or freezing

Answer 2

bonds form between particles which release energy so internal energy decreases but temp doesn’t go down until all substance has turned to liquid or solid. Flat parts of graph show the energy transfer.

Question 3

what is latent heat ?

Answer 3

energy needed to change state of substance

Question 4

specific latent heat of a substance

Answer 4

amount of energy needed to change 1kg of it from one state to another w/o changing its temperature

For cooling, SLH is the energy released by change in state

SLH is diff for diff materials and for changing between diff states

Question 5

define SLH of fusion and SLH of vaporisation

Answer 5

SLH for changing between a solid and a liquid is called SLH of fusion. The SLH for changing between liquid and gas = SLH of vaporisation

Question 6

Formula

Answer 6

Energy ( J) = mass (KG) x SLH (J/KG )