Question

The heat of combustion of methane is $-880kJmo{l}^{-1}$. The quantity of heat liberated in the combustion of $3.2g$ methane is:

• A. $-88kJ$
• B. $+88kJ$
• C. $+176kJ$
• D. $-176kJ$

Answer 1

The correct option is D $-176kJ$

Heat of combustion of methane $=$ - 880 kJ mol${}^{-1}$

3.2 g methane $=\frac{3.2}{16}=0.2$ moles

$\therefore$ Heat liberated for 0.2 moles

$=$ 0.2 x (-880) $=-$176 kJ