The difference between and , when the combustion of one mole of heptane is carried out at a temperature T, is equal to :Option 1) Option 2) Option 3)Option 4)

Can someone explain - Chemical Thermodynamics

The difference between $\Delta H$ and $\Delta U$ $\left ( \Delta H-\Delta U \right )$ , when the combustion of one mole of heptane $\left ( 1\right )$ is carried out at a temperature T, is equal to :

Option 1)
$-4\: RT$
Option 2)
$-3\: RT$
Option 3)
$4\: RT$
Option 4)
$3\: RT$

Answers (1)

S solutionqc

Combution of Heptane is -

$C_{7}H_{18}\left ( l \right )+11O_{2}\left ( g \right )\rightarrow 7CO_{2}\left ( g \right )+8 H_{2}O\left ( l \right )$

Change in gaseous moles = $7-11=-4$

$\Delta H=\Delta U+\Delta n_{g}RT$

$\Delta H-\Delta U=-4RT$

Option 1)
$-4\: RT$
Option 2)

$-3\: RT$

Option 3)

$4\: RT$

Option 4)

$3\: RT$