An expansion process on an ideal diatomic ideal gas for which C_V = 5/2 R has a linear path between the initial and final coordinates on a pV diagram. The coordinates of the initial state are: the pressure is $300 \mathrm { kPa } \text {, }$ the volume is $0.030 \mathrm {~m} ^ { 3 } ,$ and the temperature is $390 \mathrm {~K} .$ The final pressure is $150 \mathrm { kPa }$ and the final temperature is $340 \mathrm {~K} .$ What is the change in the internal (thermal)energy of the gas, during this process? (R = 8.31 J/mol ? K) A)-2900 J B)-1700 J C)2900 J D)1700 J E)0 J

Question

Quizplus · Accepted Answer

The change in internal energy is given by:$$\Delta U = C_V \Delta T = \frac{5}{2}R(T_f - T_i)$$Substituting the given values, we get:$$\Delta U = \frac{5}{2}(8.31 \mathrm { J/mol~K})(340 \mathrm { K} - 390 \mathrm { K}) = -2900 \mathrm { J}$$Therefore, the correct answer is A.

An Expansion Process on an Ideal Diatomic Ideal Gas for Which