How much heat is required to melt 2 kg of ice at 0 C, given the latent heat of fusion L = 334 kJ/kg?

How much heat is required to melt 2 kg of ice at 0 C, given the latent heat of fusion L = 334 kJ/kg?

• A. 501 kJ
• B. 668 kJ
• C. 334 kJ
• D. 1000 kJ

Answer: (B)

To melt ice at its melting point, you must provide latent heat of fusion—the energy needed per kilogram to change phase without changing temperature. The heat required is Q = m × Lf. With 2 kg and Lf = 334 kJ/kg, you get Q = 2 × 334 = 668 kJ. So about 668 kilojoules are needed. This scales with mass, so melting 1 kg would take 334 kJ, and the other numbers would correspond to different masses.

To melt ice at its melting point, you must provide latent heat of fusion—the energy needed per kilogram to change phase without changing temperature. The heat required is Q = m × Lf. With 2 kg and Lf = 334 kJ/kg, you get Q = 2 × 334 = 668 kJ. So about 668 kilojoules are needed. This scales with mass, so melting 1 kg would take 334 kJ, and the other numbers would correspond to different masses.