Heat of fusion, also called the specific latent heat of a substance, is the amount of heat energy provided to one gram of substance that changes its state from a solid to a liquid keeping pressure constant.
For example, If we want to change ice to water, a specific amount of heat is required which will be dependent upon the heat of fusion of ice and the amount of water present.
The Heat of fusion is denoted by Δl
The heat of fusion formula is given as
q = m·Δl
where
q is heat energy
m is mass
ΔHf is the heat of fusion
Example:
Find the amount of heat needed to melt 200gms of ice, if the heat of fusion of ice is 330 J/gm
Ans:
Mass of ice(m) = 200gm
Heat of fusion(Δl) = 330 J/gm
Heat needed(q) = m.Δl
= 200 x 330
=66000J or 6.6 x 104 J.
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