MISSED THIS? Watch IWE: The Mole Concept-Converting Between Mass and Number of Molecules 70.9gH2O ; Read Section 3.8. You can click on the Review link to access the section in your eText. Express your answer in molecules to three significant figures. How many molecules (or formula units) are in each sample? MISSED THIS? Watch IWE: The Mole Concept-Converting Between Mass and Number of Molecules 157mgNaNO4 Read Section 3.8. You can click on the Review Express your answer in formula units to three significant figures. link to access the section in your eText. How many molecules (or formula units) are in each sample