How much energy is required to heat a 0.20 kg ice cube from -5°C to 0°C and then melt it?

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Multiple Choice

How much energy is required to heat a 0.20 kg ice cube from -5°C to 0°C and then melt it?

The energy needed has two parts: sensible heat to raise the ice from -5°C to 0°C, and latent heat to melt the ice at 0°C. First part: Q1 = m × c_ice × ΔT = 0.20 kg × 2.1 kJ/kg·°C × 5°C ≈ 2.1 kJ. Second part: Q2 = m × L_f = 0.20 kg × 333 kJ/kg ≈ 66.6 kJ. Total energy ≈ 2.1 kJ + 66.6 kJ = 68.7 kJ, about 69 kJ. Among the given options, 67 kJ is the closest match after rounding, so that value best fits.

The energy needed has two parts: sensible heat to raise the ice from -5°C to 0°C, and latent heat to melt the ice at 0°C.

First part: Q1 = m × c_ice × ΔT = 0.20 kg × 2.1 kJ/kg·°C × 5°C ≈ 2.1 kJ.

Second part: Q2 = m × L_f = 0.20 kg × 333 kJ/kg ≈ 66.6 kJ.

Total energy ≈ 2.1 kJ + 66.6 kJ = 68.7 kJ, about 69 kJ. Among the given options, 67 kJ is the closest match after rounding, so that value best fits.

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