It was determined through analysis that a compound, sodium carbonate with a molar mass of 263 g/mol contained 68.4% water. determine the toilet number of water molecules in this hydrate

Explanation:

Hi, here I explain step by step:

1) You have 263 g/mol and 68.4% of that (in weight) is water. So for 1 mol:

2) A mol of water molecules weights 18 g/mol (16 g/mol of oxygen and 2g/mol of hydrogen):

3) Knowing Avogadro's number: 6.022*10^23 molec/mol: