What is the molar mass of water (H₂O)?

The molar mass of water (H₂O) is calculated by summing the atomic masses of its constituent elements. Water consists of two hydrogen (H) atoms and one oxygen (O) atom.

The atomic mass of hydrogen is approximately 1 g/mol, and there are two hydrogen atoms in a molecule of water, contributing a total of about 2 g/mol. The atomic mass of oxygen is approximately 16 g/mol. When you add these together for one molecule of water, the calculation is as follows:

2 (for the two hydrogen atoms) + 16 (for the one oxygen atom) = 18 g/mol.

This gives us the molar mass of water as 18 g/mol, which is the correct answer.