If a car produces 62g of CO2, how many grams of O2 are used up in the reaction?

Given:

Amount of CO2 produced = 62 g

To determine:

Amount of O2 consumed

Explanation:

If ethanol (C2H5OH) is the fuel used during combustion then the reaction is:

C2H5OH + 3O2 → 2CO2 + 3H2O

Based on the reaction stoichiometry:

3 moles of O2 will produce 2 moles of CO2

# moles of CO2 produced = 62 g / 44 g. mol-1 = 1.4091 moles

Therefore,

# moles of O2 consumed = 1.4091 * 3/2 = 2.1137 moles

Mass of O2 used up = 2.1137 moles * 32 g/mole = 67.64 g

Ans: The mass of O2 used up during combustion of ethanol would be around 68 g