Thermodynamics and Thermochemistry - Result Question 65
65. For the reaction, $2 \mathrm{CO}+\mathrm{O}_2 \rightarrow 2 \mathrm{CO}_2 ; \Delta H=-560 \mathrm{~kJ}$. Two moles of CO and one mole of $\mathrm{O}_2$ are taken in a container of volume $1 $ L . They completely form two moles of $\mathrm{CO}_2$, the gases deviate appreciably from ideal behaviour. If the pressure in the vessel changes from $70$ to $40$ atm , find the magnitude (absolute value) of $\Delta U$ at $500 \mathrm{~K} .(1 \mathrm{~L}-\mathrm{atm}=0.1 \mathrm{~kJ})$
(2006, 3M)
Show Answer
Answer:
Correct Answer: 65. $(-563 \mathrm{~kJ})$
Solution:
$\begin{aligned} & \Delta H=\Delta U+\Delta(p V)=\Delta U+V \Delta p \\ & \Rightarrow \Delta U=\Delta H-V \Delta p \\ & =-560-1 \times 30 \times 0.1=-563 \mathrm{~kJ} \\ & \end{aligned}$
BETA
