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Energy and work done by a gas system

An insulated cylinder closed at one end by a frictionless piston contains 20g of hydrogen gas at 30 degrees Celsius. This is heated to 40 degrees Celsius with the pressure kept constant at 1 bar and the volume increases by 7*10^-4 m^3. (The specific heat of H2 at constant pressure is 1.4*10^4 JKg^-1 K^-1).

a) What is the work done by the gas?

b) What is the change in internal energy of the system?

Solution Preview

Work done by a system is defined as:

And the total work of a system starting at volume Vi and ends up with volume Vf is:

In most cases, the pressure and volume are interlinked (the pressure is a function of the volume). However, in this case the pressure is constant (isobaric process).

Thus, in the integral expression for work the pressure can be taken outside of the ...

Solution Summary

Energy and work done by a gas system is analyzed. A frictionless piston contains 20 g of hydrogen gas at a specific temperature. The energy of the gas as well as the change in internal energy of the system is calculated.

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