### Thermodynamics Question 1

#### Question 1 - 24 January - Shift 2

One mole of an ideal monoatomic gas is subjected to changes as shown in the graph. The magnitude of the work done (by the system or on the system) is__________ $J$ (nearest integer).

Given : $\log 2=0.3, \ln 10=2.3$

## Show Answer

#### Answer: (620)

#### Formula: Gibb’s Free Energy

#### Solution:

$1 \to 2 \Rightarrow$ Isobaric process

$2 \to 3 \Rightarrow$ Isochoric process

$3 \to 1 \Rightarrow$ Isothermal process

$W=W _{1 \to 2}+W _{2 \to 3}+W _{3 \to 1}$

$=(-P(V_2-V_1)+0[-P_1 V_1 \ln (\frac{V_2}{V_1})])$

$=[-1 \times(40-20)+0+[-1 \times 20 \ln (\frac{20}{40})]]$

$=-20+20 \ln 2$

$=-20+20 \times 2.3 \times 0.3$

$=-6.2$ bar $L$

$|W|=6.2$ bar $1=620 J$