A sample contains 18.0 g of water (H_2O). What is the number of moles present in the sample?

• A. 1.00 mol
• B. 9.00 mol
• C. 0.50 mol
• D. 2.00 mol

Answer: (A)

Verified step by step guidance

1. Identify the given information: the mass of water (H\_2O) is 18.0 g.
2. Recall the formula to calculate moles from mass: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
3. Calculate the molar mass of water by adding the atomic masses of its elements: hydrogen (H) has an atomic mass of approximately 1.00 g/mol, and oxygen (O) has an atomic mass of approximately 16.00 g/mol. So, molar mass of H\_2O = \$2 \times 1.00 + 16.00$ g/mol.
4. Substitute the values into the formula: \(\text{moles} = \frac{18.0}{\text{molar mass of H\_2O}}\).
5. Perform the division to find the number of moles present in the 18.0 g water sample.