Question

3. Consider the reaction of methane, CH4, burning in the presence of oxygen at constant pressure. Given the following equation, how much heat could be obtained by the combustion of 8.0 grams CH4? Given the thermochemical equation: CH4(g)+2O2→CO2(g)+2H2O(l); ΔH0=890.3kJ;

Answer 1

Answer: 445.15 kJ of heat could be obtained by the combustion of 8.0 grams $CH_4$

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$    

$\text{Moles of} CH_4=\frac{8.0g}{16.04g/mol}=0.50moles$

The given thermochemical equation is:

$CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)$  $\Delta H=890.3kJ$

According to stoichiometry :

1 mole of $CH_4$ on combustion produce heat = 890.3 kJ

Thus 0.50 moles of $CH_4$ on combustion produce heat =$\frac{890.3}{1}\times 0.50=445.15kJ$

Thus 445.15 kJ of heat could be obtained by the combustion of 8.0 grams $CH_4$