How much heat melts 600 g of ice at 0°C into water at 0°C? Take Lf = 3.36 × 10⁵ J kg⁻¹.

Solution & explanation

1. Both initial and final temperatures are 0°C; only a phase change is required.

2. Convert grams to kilograms.

   $$m=\frac{600}{1000}=0.6$$

3. Use latent heat rather than mcΔT.

   $$Q=L_f\times m$$

4. Substitute mass and specific latent heat.

   $$Q=0.6\times 3.36\times {10}^5$$

5. Multiply the coefficients.

   $$Q=2.016\times {10}^5=201600$$

6. Convert joules to kilojoules.

   $$Q=\frac{201600}{1000}=201.6$$

Q = 201,600 J = 201.6 kJ