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Questions
How much heat energy is necessary to raise the temperature of 5 kg of water from 20°C to 100°C?
How much heat energy is necessary to raise the temperature of 5 kg of water from 20°C to 100°C? [c = 1 kcal/kg°C]
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Solution
Given: Mass (m) = 5 kg, specific heat of water (c) = 1 kcal/kg °C
Change in temperature (ΔT) = 100 − 20
= 80°C
According to the principle of heat exchange,
Energy supplied to water = Energy gained by water
= Mass of water × specific heat of water × rise in the temperature of water
Q = mc ΔT
Q = 5 × 1 × 80
= 400 kcal
The heat energy necessary to raise the temperature of the water is 400 kcal.
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