If 1.0 kg of water is heated from 20°C to 60°C, how much energy is added? Use c = 4.18 kJ/kg°C.

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Multiple Choice

If 1.0 kg of water is heated from 20°C to 60°C, how much energy is added? Use c = 4.18 kJ/kg°C.

The energy needed to heat something depends on its mass, how much its temperature changes, and its specific heat capacity. Use Q = m c ΔT. Here, m = 1.0 kg, c = 4.18 kJ/(kg·°C), and ΔT = 60°C − 20°C = 40°C. So Q = 1.0 × 4.18 × 40 = 167.2 kJ. This is the amount of energy added for this 40°C rise in 1.0 kg of water; the other numbers would result from different temperature changes or a different specific heat value.

The energy needed to heat something depends on its mass, how much its temperature changes, and its specific heat capacity. Use Q = m c ΔT. Here, m = 1.0 kg, c = 4.18 kJ/(kg·°C), and ΔT = 60°C − 20°C = 40°C. So Q = 1.0 × 4.18 × 40 = 167.2 kJ. This is the amount of energy added for this 40°C rise in 1.0 kg of water; the other numbers would result from different temperature changes or a different specific heat value.

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