The molar mass of water (H₂O) is 18.02 g/mol.
This value can be derived by summing the atomic masses of its constituent elements: hydrogen (H) and oxygen (O). Each hydrogen atom has an atomic mass of approximately 1.01 g/mol, and there are two hydrogen atoms in a water molecule. Thus, the total mass from hydrogen is:
- 2 x 1.01 g/mol = 2.02 g/mol
Next, the atomic mass of oxygen is about 16.00 g/mol. Therefore, the total mass contribution from oxygen is:
- 1 x 16.00 g/mol = 16.00 g/mol
When you add these two contributions together, you get:
- 2.02 g/mol + 16.00 g/mol = 18.02 g/mol
Consequently, the correct answer is option A: 18.02 g.