Question

Lithium and oxygen react explosively to form Lithium oxide. How many moles of oxygen are required to form 7.25 moles of Lithium?

Answer 1

Moles of O2 = 1.81 mol

Explanation

Given:

moles of Lithium = 7.25 mol

Required: moles of oxygen.

Solution

Step 1: Write the reaction and balance it.

The reaction of Li and O is as follows:

`4Li\text{ + O}_2\rightarrow2Li_2O`

Step 2: Use the stoichiometry to calculate the moles of oxygen.

The molar ratio between Li and O2 is 4:1

Therefore the moles of O2 = 7.25 x (1/4) = 1.81 mol