Answer:
3.586 mol of H2O (correct to 4 sig figs)
Explanation:
Known: 64.60 g water (a.k.a. H2O)
1 mol of H2O = 18.015g
How did I get that mass? Looking at the periodic table and adding atomic mass of 2 hydrogens + 1 oxygen ( 2(1.008) +15.999) = 18.015g
How many of mol of H2O will form?
Solving for the unknown:
64.60g • (1 mol H2O / 18.015g H2O) = 3.58590 mol H2O