Step 1: Identify the elements in water (H2O). There are 2 hydrogen (H) atoms and 1 oxygen (O) atom.
Step 2: Find the atomic weight of hydrogen. The atomic weight of hydrogen is approximately 1 g/mol.
Step 3: Find the atomic weight of oxygen. The atomic weight of oxygen is approximately 16 g/mol.
Step 4: Calculate the total weight of hydrogen in water. Since there are 2 hydrogen atoms, multiply the atomic weight of hydrogen by 2: 2 * 1 g/mol = 2 g/mol.
Step 5: Add the total weight of hydrogen to the weight of oxygen: 2 g/mol (from hydrogen) + 16 g/mol (from oxygen) = 18 g/mol.
Step 6: Conclude that the molecular weight of water (H2O) is 18 g/mol.
