How mny moles of Mg would you need to react with 2.5 moles of O2?

Answer 1

Start with a balanced equation, we will assume that the product is MgO

Mg + O2 -> MgO

which we need to balance

2Mg + O2 -> 2MgO

so 1 mole of O2 reacts with 2 moles of Mg

so 2 moles of O2 reacts with 4 moles of Mg

hence 2.5 moles of O2 reacts with ?? moles of Mg