Question

$4.8g$ of $C$ (diamond) on complete combustion evolves $1584kJ$ of heat. The standard heat of formation of gaseous carbon is $725kJ/mol$. The energy required for the process
(i) $C$ (graphite) $\to C$ (Gas) (ii) $C$ (diamond) $\to C$ (gas) are:

• A. $725,727$
• B. $727,725$
• C. $725,723$
• D. None of these

Answer 1

The correct option is A $725,727$

$C\left(graphite\right)\to C\left(gas\right)$

$\Delta H=725$ $kJ/mol$ (given)

As graphite is thermodynamically more stable than diamond. Therefore, the heat required to convert graphite to gaseous should be more.