If 7.6 moles of magnesium react with excess oxygen, how many moles of magnesium oxide can be produced?

Answer 1

the underlying chemical reaction that you have happening here is

2Mg + O2 ​→ 2MgO

based on the coefficients, the mole ratio here between Mg and MgO is 2:2 = 1:1, meaning that the number of magnesium oxide produced will be equal to the number of moles of magnesium produced

so 7.6 moles of magnesium will produce 7.6 moles of magnesium oxide

Answer 2

Balance the reaction to get mole ratios: 2 Mg + O₂ --> 2 MgO. Then (7.6 mole Mg) * (2 mole MgO / 2 mole Mg) = 7.6 mole MgO.