For the question(s) that follow, consider the following balanced equation.
Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH) ₂(s) + 2NH₃(g)
-How many grams of CO₂ are produced from 125 g of O₂ and excess CH₄?
CH₄ + 2O₂ → CO₂ + 2H₂O

Question

Quizplus · Accepted Answer

Since the equation is balanced in terms of moles, we need to first convert 125 g of O₂ to moles using its molar mass (32 g/mol). 
125 g O₂ * (1 mol O₂/32 g O₂) = 3.91 mol O₂
From the balanced equation, we see that 1 mol of O₂ produces 1 mol of CO₂, so 3.91 mol of O₂ will produce 3.91 mol of CO₂. 
Now we can convert moles of CO₂ to grams using its molar mass (44 g/mol).
3.91 mol CO₂ * (44 g CO₂/1 mol CO₂) = 172.04 g CO₂
Rounding to three significant figures gives the answer of 85.9 g CO₂.

For the Question(s) That Follow, Consider the Following Balanced Equation