Which of the following is the molar mass of water (H_2O)?

• A. 20.02 g/mol
• B. 2.02 g/mol
• C. 16.00 g/mol
• D. 18.02 g/mol

Answer: (D)

Verified step by step guidance

1. Identify the elements present in the water molecule (H_2O), which are hydrogen (H) and oxygen (O).
2. Determine the number of atoms of each element in one molecule of water: 2 hydrogen atoms and 1 oxygen atom.
3. Find the atomic masses of hydrogen and oxygen from the periodic table: approximately 1.01 g/mol for hydrogen and 16.00 g/mol for oxygen.
4. Calculate the total molar mass of water by multiplying the atomic mass of each element by the number of atoms and then summing these values: \(\text{Molar mass} = (2 \times 1.01) + (1 \times 16.00)\) g/mol.
5. Add the values to get the molar mass of water, which will be close to 18.02 g/mol.