Question

What is the percent of O in
CO2?
(C = 12.01 amu, O = 16.00 amu)
[? ]%

Answer 1

This is percent composition
The formula for that is
(Mass of part/total mass) x 100

What’s the total molar mass of CO2?
12.01 +16(2) = 44.01 g/mol

What is the molar mass of Carbon?
Since there is only one carbon it is 12.01 g/mol

(12.01/44.01) x 100 = 27.29%