CH₄ + 2 O₂ → CO₂ + 2 H₂O. 50 g of CH₄ and 120 g of O₂ react with each other. The reactant O₂ is in excess here. (Molar masses: C = 12 g; H = 1 g; O = 16 g)

Question

Quizplus · Accepted Answer

The molar mass of CH4 (methane) is 16 g/mol (12 g for carbon + 4 g for hydrogen), and the molar mass of O2 is 32 g/mol (16 g x 2 for oxygen). Given 50 g of CH4, we have 50 g / 16 g/mol = 3.125 moles of CH4. For O2, 120 g / 32 g/mol = 3.75 moles of O2. The reaction between methane (CH4) and oxygen (O2) to produce carbon dioxide (CO2) and water (H2O) typically requires a 2:1 molar ratio of O2 to CH4. Therefore, with 3.125 moles of CH4, we would need 6.25 moles of O2 to react completely, but only 3.75 moles of O2 are provided, making CH4 in excess, not O2.

CH4 + 2 O2 → CO2 + 2 H2O

CH₄ + 2 O₂ → CO₂ + 2 H₂O