A house has wellinsulated walls It contains a volume of 110

A house has well-insulated walls. It contains a volume of 110 m³ of air at 305 K.

(a) Consider heating it at constant pressure. Calculate the energy required to increase the temperature of this diatomic ideal gas by 0.7°C.
kJ

(b) If this energy could be used to lift an object of mass m through a height of 1.2 m, what is the value of m?
kg

Solution

a.) For an isobaric process, we know that the work done on a gas is obtained by

W = nR x Change in temperature.

Hence Work done = 2 x 8.314 x 0.7 = 11.64 J

Therefore the energy required is 11.64 J

b.) If this energy is used to lift an object of mass m through a height of 1.2 m, the change in potential energy will be equal to the energy supplied

Hence, 11.64 = m x 9.81 x 1.2

That is, m = 11.64 / 9.81*1.2 = 0.98 kg