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 $1=620 J$
