The estimated average daily requirement of potassium is 4.7 g. Given that potassium has a molar mass of 39.10 g/mol, what is this in moles?

1. Moles are found by dividing the mass in grams by the molar mass in grams per mole. 2. Potassium has an atomic mass of 39.10 amu, so its molar mass is 39.10 g/mol. 3. Dividing gives 4.7 g / 39.10 g/mol = 0.12 mol. 4. As a check, 4.7 g is a little more than one tenth of 39.10 g, so the answer must be slightly above 0.1 mol. 5. The value 8.32 mol comes from dividing the molar mass by the mass, which inverts the calculation. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.1 Formula Mass and the Mole Concept_