Question

What is the number of moles in 18 g of water (\( \text{H}_2\text{O} \))?

• A. 1 mol
• B. 0.5 mol
• C. 2 mol
• D. 0.25 mol

Hint:

Remember: The number of moles is calculated using \( n = \frac{\text{mass}}{\text{molar mass}} \).

Answer 1

The Correct Option is A

Given: The mass of water is 18 g. Step 1: Molar Mass of Water The molar mass of water (\( \text{H}_2\text{O} \)) is calculated as: \[ \text{Molar Mass of H}_2\text{O} = 2 \times \text{(atomic mass of H)} + \text{(atomic mass of O)} = 2 \times 1 + 16 = 18 \, \text{g/mol} \] Step 2: Calculate the Number of Moles The number of moles \( n \) is given by: \[ n = \frac{\text{mass}}{\text{molar mass}} = \frac{18 \, \text{g}}{18 \, \text{g/mol}} = 1 \, \text{mol} \] Answer: The correct answer is option (1): 1 mol.