The number of moles of methane required to produce 11 g CO₂(g) after complete combustion is : (Given molar mass of methane in g mol⁻¹: 16 )

Solution

Chemistry ma’am · 4 steps

Each CH₄ gives exactly one CO₂, so find moles of CO₂ and you have moles of methane.

1. Balanced equation. Methane burns completely to carbon dioxide and water.

   CH₄ + 2O₂ → CO₂ + 2H₂O

2. Moles of CO2. Molar mass of CO₂ is 12 + 2 × 16 = 44 g mol⁻¹. So 11 g is 11/44 = 0.25 mol.
3. Use the ratio. The equation has a 1 : 1 ratio between CH₄ and CO₂, because methane has one carbon atom and each carbon ends up in one CO₂.
4. So. Moles of methane needed = 0.25 mol, which is option (b).

The idea to keep. In combustion questions, follow the carbon atoms: moles of CO₂ formed equal moles of C in the fuel. Convert the given mass to moles first, then use the mole ratio.

Answer from the NTA final answer key. Solution by PrepWiser.