Question

In a process, the pressure and volume of a given mass of gas increase. Then :

• A. it is impossible
• B. the system does a positive work
• C. the temperature of the system must increase
• D. $\Delta Q=\Delta U$

Answer 1

Answer: (B), (C)

The correct options are
B the temperature of the system must increase
C the system does a positive work

Given that pressure and volume increase

$P{}_2>P{}_1$ and $V{}_2>V{}_1$

From ideal gas law

$\frac{P_1{V}_1}{T_1}=\frac{P_2{V}_2}{T_2}$

$\frac{P_1{V}_1}{T_1}=\frac{P_2{V}_2}{T_2}{T}_2=\frac{P_2{V}_2}{P_1{V}_1}{T}_1(\frac{P_2}{P_1}>1,\frac{V_2}{V_1}>1)$

Then temperature of the system will also increase

$Work={\int }_1^{2}PdV$

Since $V_2>V_1$

The system will do a positive work.