Answer to Question #113883 in Physical Chemistry for Jamie

Question

How many moles of magnesium oxide is produced when 0.27 moles of oxygen gas reacts completely

Answer 1

Let's write a balanced reaction equation:

2Mg + O₂ $\rightarrow$ 2MgO.

As you see from the stoichiometric coefficients, when 1 molecule of oxygen reacts, 2 molecules of magnesium oxide are produced. Therefore, the number of the moles of the oxygen and magnesium oxide relate as:

$n(O_2) = n(MgO)/2$ .

When 0.27 moles of oxygen reacts completely:

$n(MgO) = 2·n(O_2) = 2·0.27 = 0.54$ mol

Answer: 0.54 mol of magnesium oxide is produced when 0.27 moles of oxygen gas reacts completely.