Question

How much energy is required to change $2Kg$ of ice at $0^{0}C$ into water at ${20}^{0}C$? (specific latent of heat of fusion of water = $3,34,000J/Kg$, specific heat capacity of water = $4200J{Kg}^{-1}{K}^{-1}$).

Answer 1

Total heat= $\left[\text{Heat required to convert 2 kg of ice to 2 kg of water at}{O}^{o}C\right]+$

$\left[\text{Heat required to convert 2 kg of water at}{o}^{o}C\text{to 2kg of water at}{20}^{o}C\right]$

$=m{h}_{fg}+m{C}_p\Delta T$

$=(2\times 334kJ)+(2\times 4.2\times 20)$

$=668+168=836kJ$ of heat is required.