Question

An ideal gas in a cylinder is compressed very slowly to one-third its original volume while its temperature is held constant. The work required to accomplish this task is 77 J.

(a) What is the change in the internal energy of the gas? __________J

(b) How much energy is transferred to the gas by heat in this process?____________J

Answer 1

(a)

This is the case of isothermal compression process. In Iso-thermal process, the change in internal energy is zero.

Thus, the change in internal energy of the gas is Zero

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(b)

In this case, the change in internal energy is zero. Hence, the energy transfered to the gas is equal to work done in accordance with the first law of thermodynamics. All the work done by the gas is equal to energy is transferred.

   Q = - W = - 77 J