Question

The molecular weight of water, H2O, is 18.02 g/mol. How many moles of water are in 24.3 g of water?

Answer 1

Explanation:

MW = 2(1.01) + 16.00 = 18.02 g/mol

Divide the number of grams by the molecular weight in g/mol. In this question, the two are the same number, so when you divide, you get 1. That is the number of moles of H2O in 18.02 g of H2O. So you have 1 mole of water, and 1 mole contains Avogadro's number of molecules, which is 6.02 x 1023.