Thermodynamics and Thermochemistry - Result Question 65
####65. For the reaction, $2 CO+O _2 \rightarrow 2 CO _2 ; \Delta H=-560 kJ$. Two moles of $CO$ and one mole of $O _2$ are taken in a container of volume $1 L$. They completely form two moles of $CO _2$, 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 $500 K$. ( $1 L$-atm $=0.1 kJ)$
(2006, 3M)
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Solution:
- $\Delta H=\Delta U+\Delta(p V)=\Delta U+V \Delta p$
$$ \begin{aligned} \Rightarrow \quad \Delta U & =\Delta H-V \Delta p \ & =-560-1 \times 30 \times 0.1=-563 kJ \end{aligned} $$
