Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2Mg(s) + O₂(g) → 2MgO(s)
How many moles of O₂ are consumed when 0.770 mol of magnesium burns?

Question

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2Mg(s)+ O₂(g)→ 2MgO(s) How many moles of O₂ are consumed when 0.770 mol of magnesium burns?

Quizplus · Accepted Answer

From the balanced chemical equation, we see that the mole ratio between magnesium and oxygen gas is 2:1. Therefore, for every 2 moles of magnesium that reacts, 1 mole of oxygen gas is consumed. 
In this problem, we are given 0.770 mol of magnesium, so we need to determine how many moles of oxygen gas are consumed. 
(0.770 mol Mg) x (1 mol O2 / 2 mol Mg) = 0.385 mol O2 
Therefore, the answer is choice E, 0.385.

Magnesium Burns in Air with a Dazzling Brilliance to Produce