Question

Calculate the total amount of heat energy required to melt 200 g of ice at 0°C to water at 100°C. (Specific latent heat of ice = 336 Jg^-1, specific heat capacity of water = 4.2 Jg^-1 °C^-1)

Answer 1

200 g of ice at 0°C

Q₁ = mL_f

200 g of H₂O at 0°C

Q₂ = m × c × θ_R

200 g of H₂O at 100°C

Total heat required

Q = Q₁ + Q₂ 

= mL_f + m × c × θ_R

= (200 × 336) + (200 × 4·2 × 100)

= (67200) + (84000)

= 1,51,200 J