Question

Suppose that you want to make 12 g of lithium oxide.

What are the minimum masses of lithium and oxygen you will need?

A. Li= 5.6 g O2= 6.4 g
B. Li 6.5 g O2= 4.6 g
C. Li= 0.6 g O2 46.4 g
D. Li= 15.6 g O2 6.4 g

Answer 1

A. Li= 5.6 g O2= 6.4 g

Step-by-step explanation:

Lithium oxide, Li2O, is an oxide that contains 2 moles of Li and 1 mole of O per mole of oxide. To solve this question we must find the mass of each atom in the molecule as follows:

2Li = 2*6.941g/mol = 13.882g/mol

O = 1*16g/mol = 16g/mol

Molar mass Li2O:

16+13.882 = 29.882g/mol

The mass of lithium is:

12g * (13.882g/mol / 29.882g/mol) = 5.6g Li

And the mass of oxygen:

12g * (16g/mol / 29.882g/mol) = 6.4g O

Right answer is:

A. Li= 5.6 g O2= 6.4 g