If you have the moles of each reactant, you use the molar ratios to calculate the moles of product that each reactant can form.
Methane burns in oxygen to give carbon dioxide and water according to the equation:
CH₄ + 2O₂ → CO₂ + 2H₂O
In one experiment, you burned a mixture of 0.250 mol of methane and 1.25 mol of oxygen in a sealed steel vessel. How many moles of CO₂ did you get?
a. Calculate the amount of CO₂ that forms from the CH₄.
0.250 mol CH₄ ×
b. Calculate the amount of CO₂ that forms from the O₂.
1.25 mol O₂ ×
c. Since CH₄ gives fewer moles of CO₂, CH₄ is the limiting reactant.
d. Amount of CO₂ = 0.250 mol