Question

a. 100 J of heat energy are transferred to 20 g of mercury. By how much does the temperature increase?
b. How much heat is needed to raise the temperature of 20 g of water by the same amount?

Answer 1

a)

Given that

Heat energy Q = 100 J

mass of mercury m = 20 x 10^-3 kg

Heat capacity of mercury is c = 138 J/kg.oC

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The amount of heat energy is

            Q = mc ΔT

The temperature increase is

           ΔT = Q/(mc)

                 = (100 J)/((20x 10^-3 kg)(138 J/kg.oC))

                 = 36.23^oC

b) The amount of heat energy is

        Q = mc ΔT

   

Here heat capacity of water is c = 4186 J/kg.^oC

          Q= ( 20 x 10^-3 kg)(4186 J/kg.^oC)( 36.23^oC)

               = 3033.1756 J