5.6 liters of of methane gas (CH4) is ignited in oxygen gas. Calculate the number of moles of CO2 formed  

CH₄ + 2O₂ → 2H₂O + CO₂

1 mole of methane gives 1 mole of CO₂ gas.Therefore, at STP; 5.6 L of methane will give 5.6 L of CO2 gas.

Volume occupied by 1 mole a gas at STP = 22.4 L

Therefore,

Number of moles in 5.6 L of CO₂ gas = 5.6/22.4  

  = 0.25 moles.