Question

How many molecules in 1 gram of water?

Answer 1

We should convert this into moles of water first, then from there we can convert to the molecules using Avogadro's number.
Do you know how to convert between grams and moles?

Answer 2

No I do not, can you help me?

Answer 3

To convert between grams and moles, we need the molar mass of water. \(\rm H_2 O \). The molar mass has units of grams per 1 mole. So we divide mass by molar mass (grams by grams per mole) to get back moles of \(\rm H_2 O\).