Energy required to raise 1 kg of water by 3°C?

Energy required to raise 1 kg of water by 3°C?

• A. 12.54 kJ
• B. 4.18 kJ
• C. 1.254 kJ
• D. 25.0 kJ

Answer: (A)

Energy required to raise the temperature of a substance depends on its mass, its specific heat capacity, and how much the temperature changes: Q = m c ΔT. For water, the specific heat capacity is about 4.18 kJ per kilogram per degree Celsius. With 1 kilogram of water and a temperature rise of 3°C, the heat needed is Q = 1 × 4.18 × 3 = 12.54 kJ. So 12.54 kJ is the correct amount of energy. The other numbers correspond to different temperature changes: 4.18 kJ would heat 1 kg by 1°C, 1.254 kJ would heat it by 0.3°C, and 25.0 kJ would heat it by about 6°C.

Energy required to raise the temperature of a substance depends on its mass, its specific heat capacity, and how much the temperature changes: Q = m c ΔT. For water, the specific heat capacity is about 4.18 kJ per kilogram per degree Celsius. With 1 kilogram of water and a temperature rise of 3°C, the heat needed is Q = 1 × 4.18 × 3 = 12.54 kJ. So 12.54 kJ is the correct amount of energy.

The other numbers correspond to different temperature changes: 4.18 kJ would heat 1 kg by 1°C, 1.254 kJ would heat it by 0.3°C, and 25.0 kJ would heat it by about 6°C.