Answer to Question #75255 in General Chemistry for Khelsea

Question

The Principal constituent of natural gas is methane, which burns in air by this reaction:
CH4 + 2O2 (arrow to the right) 2H2O + CO2
How many grams of O2 are needed to produce 3.5 gms of CO2?

Answer 1

Calculate number of moles of CO2 = mas s/ MW = 3.5 g / 44 g/mole = 0.08 moles
Therefore, number of moles of O2= 2 x 0.08 moles = 0.16 moles (from stoichiometry of the reaction)
Grams of O2 =moles x MW = 0.16 moles x 32 g/mol = 5.1 g O2