Two moles of magnesium (mg) and five moles of oxygen (o2) are placed in a reaction vessel. when magnesium is ignited, it reacts with oxygen. what is the limiting reactant in this experiment?
mg + o2 → mgo (unbalanced)
a.
mg
b.
o2
c.
mgo
d.
both the reactants are in same proportion

Explanation:

We are given the amounts of two reactants, so this is a limiting reactant problem.

We know that we will need moles, so, lets assemble the data in one place.

           2Mg + O₂ ⟶ 2MgO

n/mol:    2       5

Calculate the moles of MgO we can obtain from each reactant.

From Mg:  

The molar ratio of MgO:Mg is 2:2

From O₂:  

The molar ratio of MgO:O₂ is 2:1.

b.

the accuracy of the data.