Question

a 3.75-gram sample of limestone, caco3, contains 1.50 g of calcium and 0.450 g of carbon. what is the percent oxygen in limestone?

Answer 1

Compute the mass of O in the given sample of CaCO₃ :

3.75 g - 1.50 g - 0.450 g = 1.80 g

This mass of oxygen makes up

(1.80 g) / (3.75 g) = 0.48 = 48%

of the sample's mass.