Question

A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If $\Delta$H is the enthalpy change and $\Delta$E is the change in internal energy, then:

• A. $\Delta H>\Delta E$.
• B. $\Delta H<\Delta E$.
• C. $\Delta H=\Delta E$.
• D. the relationship depends on the capacity of the vesssel.

Answer 1

The correct option is B $\Delta H<\Delta E$.

$2CO+O_2\to 2C{O}_2$

$\Delta n$ = no. of moles of gaseous product$-$no. of moles of gaseous reactant

$\Delta n=2-(2+1)=-1$

$\Delta H=\Delta E+\Delta nRT$

$\Delta H=\Delta E+(-1)RT$

$\Delta H=\Delta E-RT$

$\Delta H<\Delta E$

Hence,option B is correct.