Number of moles of methane required to produce 22 g CO_(2( g)) after combustion is x × 10⁻² moles. The value of x is _________.

Solution

Chemistry ma’am · 3 steps

Each CH₄ has exactly one carbon, so moles of CH₄ burnt equal moles of CO₂ formed.

1. Balanced equation. Methane burns as shown below. The ratio of CH₄ to CO₂ is 1 : 1.

   CH₄ + 2O₂ → CO₂ + 2H₂O

2. Moles of CO2. Molar mass of CO₂ is 12 + 2 × 16 = 44 g mol⁻¹. So 22 g is 22/44 = 0.5 mol.
3. So. Moles of CH₄ needed = 0.5 = 50 × 10⁻² mol, so x = 50.

The common slip: 0.5. Reporting the moles directly gives 0.5, but the answer asks for x in x × 10⁻², which is 50.

The idea to keep. In combustion questions, count the carbon atoms. Each carbon in the fuel ends up in one CO₂, so the mole ratio comes straight from the formula.

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