Given the following chemical reaction: 2 O2 + CH4 CO2 + 2 H2O What mass of CH4 is required to completely react with 100 grams of O2? 6 C 12.01 Carbon 1 H 1.01 Hydrogen 8 O 16.00 Oxygen A. 10 grams CH4 B. 20 grams CH4 C. 25 grams CH4 D. 45 grams CH4

The mass methane (CH4) required is, 25 grams (option C)

Explanation:

Mass of oxygen gas = 100 g

Molar mass of oxygen gas = 32 g/mole

Molar mass of methane gas = 16 g/mole

Step 1: Balance the reaction

2O2 + CH4 → CO2 + 2H2O

Step 2: Calculate the moles of O2:

Moles O2 = mass of O2 / Molar mass of o2

Moles O2 = 100g / (32g/mole) = 3,125 moles

⇒From the balanced reaction we conclude that 2 moles of O2 react with 1 mole of CH4

⇒ So, 3.125 moles of O2 react with 3.125/2 = 1.563 moles of CH4

Step 3: Calculate the mass of CH4:

Mass of CH4 = moles of CH4 x Molar mass of CH4

Mass of CH4 = 1.563 moles / (16g / moles) = 25.008 grams CH4