The energy required to melt 100 g of ice at 0°C using the same latent heat value ΔHf = 333.55 J/g is?

• A. 16,676 J
• B. 33,355 J
• C. 66,710 J
• D. 10,000 J

Answer: (B)

Melting at a fixed temperature requires energy equal to the mass times the latent heat of fusion. Use Q = m ΔHf. With 100 g of ice and ΔHf = 333.55 J/g, the energy needed is 100 × 333.55 = 33,355 J. So the required energy is 33,355 joules (about 33.355 kJ). The other values would correspond to melting different masses (for example, 50 g would need about 16,676 J, 200 g would need about 66,710 J, and 30 g would need about 10,000 J), not the 100 g in this problem.