Question

The enthalpy of combustion of methane is 890 kJ/mol. How much heat is released when 8 g of methane is burned completely? (Molar mass of CH\(_4\) = 16 g/mol)

• A. 445 kJ
• B. 222.5 kJ
• C. 890 kJ
• D. 1780 kJ

Hint:

To calculate the heat released during combustion, multiply the enthalpy of combustion by the number of moles of the substance burned.

Answer 1

The Correct Option is A

The number of moles of methane (\(n\)) in 8 g is: \[ n = \frac{\text{Mass}}{\text{Molar mass}} = \frac{8}{16} = 0.5 \, \text{mol} \] The enthalpy of combustion of methane is 890 kJ/mol. Therefore, the heat released when 0.5 moles of methane is burned is: \[ \text{Heat released} = 0.5 \times 890 = 445 \, \text{kJ} \]
Final answer
Answer: \(\boxed{445\, \text{kJ}}\)