How many grams of oxygen are contained in 10.0 g of KClO4?

Question

How many grams of oxygen are contained in 10.0 g of KClO4?

Answer 1

First we must convert grams of KClO4 to moles of KClO4. Second, convert moles KClO4 to moles Oxygen. Lastly, convert to grams contained in one mole Oxygen.

10.0g KClO4 X (1 mol KClO4/ 138.55 g KClO4) X (4 mol O / 1 mol KClO4) X (16.0g O / 1 mol O) = 4.61922768 g O

4.62g O  is the correct answer to three significant figures.