Question

The specific heat capacity of silver is 0.24J/C.g .

Calculate the energy required to raise the temperature of 151.0 g from 278 K to 299 K.

Energy = J

Calculate the energy required to raise the temperature of 1.0 mole of by 1.0°C (called the molar heat capacity of silver).

Molar heat capacity = J/°C ⋅ mol

It takes 1.38 kJ of energy to heat a sample of pure silver from 11.4°C to 15.1°C.

Calculate the mass of the sample of silver. Mass = g

Answer 1

Ans. #1. # Heat gained by a sample during increase in its temperature is given by-

q = m s dT                            - equation 1

Where,

q = heat gained

m = mass of sample

s₁ = specific heat of sample

dT = Final temperature – Initial temperature = (T2 – T1)⁰C

                        = 299 K – 278 K = 21 K = 21⁰C

Note that the difference , dT in both the units K and ⁰C is the same.   

Putting the values in equation –

            q = 151.0 g x 0.24 J g^-10C^-1 x 21.0⁰C = 761.04 J

#2. Given – specific heat of Ag = 0.24 J g^-10C^-1

Now, molar heat capacity of Ag = Specific heat x MW

                                                = 0.24 J g^-10C^-1 x 107.8682 g mol^-1 = 25.89 J mol^-10C^-1

Now, Putting the values in equation –

            q = 1 mol x 25.89 J mol^-10C^-1 x 1.0⁰C = 25.89 J

#3.