Discussion Forum

1)

Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at 27° C ?

 (R=2 cal K^-1 mol^-1)

Answer:

Option C

Explanation:

 Given,

 T=27° C=300K

 R= 2 cal K^-1 mol^-1

 Reaction for combustion of carbon monoxide is given as :

$CO(g)+\frac{1}{2}O_{2}(g)\rightarrow CO_{2}(g)$

 $\therefore$      $\triangle n_{g}=1-1.5=-\frac{1}{2}$

 Now, the difference between  heat of combustion of carbon monoxide gas at constant pressure and at constant volume is given by

$\triangle H -\triangle U= \triangle n_{g} RT$

$\therefore$     $\triangle H -\triangle U=-\frac{1}{2}\times 2\times300=-300 cal$