Question

What volume of oxygen is required to burn completely a mixture of 22.4 dm³ of methane and 11 .2 dm³ of hydrogen in to carbon dioxide and steam? Equations of the reactions are given below:
CH₄ + 2O₂ → CO₂ + 2H₂O
2H₂ + O₂ → 2H₂O

Answer 1

CH₄ + 2O₂ → CO₂ + 2H₂O
1 vol. 2 vol.    1 vol. 2 vol.
One volume of methane requires oxygen = 2 vol.
So, Vol. of oxygen used = 2 x 22.4 = 44.8 dm³
2H₂ + O₂  → 2H₂O
  2 vol. 1 vol. 2 vol.
2 volume of hydrogen needs one volume of oxygen
So, Volume of oxygen used = 22.4 / 2 = 11.2 dm³
Total volume of oxygen used = 44.8 + 11.2 = 56.0 dm³