Stoichiometry unit

Question

In the reaction

Mg (s)   +   O₂ (g)    →   MgO (s),

how many moles of oxygen are needed to produce 4.00 moles of magnesium oxide?

Answer 1

From the balanced chemical reaction, 1 mol of MgO is produced when 1 mol of O₂ reacts. This is your stoichiometry mole ratio. Use this mole ratio to convert mol MgO to mol O₂.

4.00 mol MgO x (1 mol O₂ / 1 mol MgO) = 4.00 mol O₂