Question

Suppose an amount of heat ΔQ supplied to a substance changes its temperature from T to T + ΔT. Heat capacity of a substance to be S = ΔQ/ΔT. We expect ΔQ and, therefore, heat capacity S to be proportional to the mass of the substance. Further, it could also depend on the temperature, i.e., a different amount of heat may be needed for a unit rise in temperature at different temperatures. To define a constant characteristic of the substance and independent of its amount, we divide S by the mass of the substance m in kg: s = S/m = (1/m) ΔQ/ΔT, s is known as the specific heat capacity of the substance. It depends on the nature of the substance and its temperature. The unit of specific heat capacity is J kg-1 K-1

A block of ice is heated until it melts completely. What happens to the temperature of ice water mixture during this process?

ASSERTION: If two different substances of equal mass at different temperature are mixed with each other equilibrium temperature is always different from their mean temperature. REASON: Two substances have different specific heat capacity.

Calculate the heat energy required to raise temperature of 500g water from 20°C to 80°C. (Specific heat capacity of water = 4.186 J/g°C)