How many atoms of Oxygen are there in 15 g of sodium bicarbonate?

Question

Sodium bicarbonate (NaHCO3) is commercially known as baking soda.         

(Molar mass of NaHCO3 = 84.01 g/mol) 

Answer 1

First you can divide the given weight by the molar mass in order to get the number of moles

15 g / (84.01 g/mol) = 0.1786 mol NaHCO₃

the subscript on Oxygen is 3 which means that there are 3 moles of Oxygen atoms for every 1 mole of sodium bicarbonate

0.1786 mol x 3 mol / 1 mol = 0.5358 mol O₂

finally then you want to multiply by Avogadro's number to convert over into atoms of oxygen

0.5358 mol O x 6.022 x 10^23 atoms/mol = 3.23 x 10^23 atoms

meaning that there are approximately 3.23 x 10^23 atoms of oxygen in 15 g of sodium bicarbonate

Answer 2

15 g baking soda 48 grams of Oxygen

84.01 g of Baking soda 23* 1 (one Na)+ 1.01 *1 16* 3

15 * 48

84

8.57 grams of oxygen

Molar mass of Baking soda= 23* 1 (one Na)+ 1.01 *1(one H) 16* 3( three O)

This gives me information that 84 grams of Baking soda contain 48 grams of Oxygen