Question

The standard heat of combustion of graphite carbon is -393.5 KJ mol${}^{-1}$. The standard enthalpy

of CO${}_2$ is

• A. +393.5 KJ mol${}^{-1}$
• B. -393. 5 KJ mol${}^{-1}$
• C. +196.75 KJ mol${}^{-1}$
• D. -196.75 KJ mol${}^{-1}$

Answer 1

The correct option is B -393. 5 KJ mol${}^{-1}$

$C\left(s\right)+O_2\left(g\right)\to C{O}_2\left(g\right)$
$\Delta H=-393.5KJmo{l}^{-1}$
formation of $C{O}_2$ equation
C (graphite) + $O_2\left(g\right)\to C{O}_2\left(g\right)$
$\Delta H=-393.5KJmo{l}^{-1}$

Hence, the correct option is $B$