Question

When four moles of $O_2$ is used for complete combustion of methane.$1600kJ$ of heat is evolved.The calorific value of methane is ?

• A. $100kJ/g$
• B. $800kJ/g$
• C. $50kJ/g$
• D. $1600kJ/g$

Answer 1

The correct option is C $50kJ/g$

$C{H}_4+2O_2⟶C{O}_2+2H_{2}O$ $\Delta H_f$

$\Rightarrow$ for $1$ mole methane $2$ mole of oxygen is used.

$\Rightarrow$ for $2$ mole methane $4$ mole of oxygen is used.

$\Rightarrow$ For $2$ mole $\Delta H=1600$

$\Rightarrow$ For $1$ mole $\Rightarrow \frac{\Delta H}{2}=800KJ$

For $1g$ of $C{H}_4\Rightarrow \frac{800}{16}=50KJ$