Question

Temperature of 5 moles of gas is decreased by 2 K at constant pressure. Indicate the correct statement.
A. Work done by gas is 5R
B. Work done by gas is 10 R
C. Work done over the gas is 10R
Work done is 0

Answer 1

Answer:

According to that correct statement is "work done over the gas is 10R

Answer 2

The correct statement among the following is that the work done over the gas is equal to 10R.

• The work done is equal to -PdV.
• In chemistry, the work is done by the gas if the work done is negative and the work is done over the gas if the work done is positive.
• We know that, PV = nRT , so differentiating this we get, PdV+ VdP = nRdT.
• Since pressure is constant, VdP=0, hence PdV = nRdT, so work done is equal to -nRdT.
• Substituting the values we get work done to be 10R.