Question

10g of ice at 0℃ absorbs 5460 J of heat energy to melt and change to water at 50℃. Calculate the specific latent heat of fusion of ice. Specific heat capacity of water is 4200 J kg^-1  K^-1.

Answer 1

Given, Mass of ice = 10g 

Heat energy absorbed (Q) = 5460 J

Specific heat capacity of water = 4200 J kg^-1 K^-1 = 4.2 J g^-1 K^-1

Specific latent heat of fusion of ice = ?

(i) Heat energy required to melt the ice at 0° C to water at 0° C (Q₁) = m × L

Substituting the values in the formula we get,

Q₁ = 10 × L

(ii) Heat energy required to raise temperature from 0° C to 50° C = m × c × rise in temperature

Substituting the values in the formula we get,

Q₂ = 10 × 4.2 × 50

Q₂ = 2100 J

Then,

Q = Q₁ + Q₂

∴ 5460 J = 10 × L + 2100 J

∴ 5460 J - 2100 J = 10 × L

∴ 3360 = 10 × L

∴ `3360/10` = L

∴ L = 336 Jg^-1