Question

If you start with 5 molecules of O2 in the reaction 2Mg + O2 2 MgO, how much Mg will you need

Answer 1

2Mg + O₂ ---> 2MgO

2 atoms Mg --- 1 molecules O₂
X atoms Mg --- 5 molecules O₂
X = 2×5
X = 10 atoms Mg