Question

32.0 g of water is produced during a combustion. how many moles of H2O were produced in the reaction?

Answer 1

use the formula

\[moles = \frac{grams}{Molecular Mass}\]

The molecular mass of water can be found by looking at the periodic table and adding up the atomic mass of all the atoms in the element waters molecular formula is H2O
thus it has 2 Hydrogens and 1 oxygen

Thus its molecular mass is:

1.000794 + 1.000794 + 15.9994 = 18g/mol

Remember units for molecular mass is grams per mole