Question

How many moles are there in 18 grams of water ($ \text{H}_2\text{O} $)? (Atomic masses: H = 1, O = 16)

• A. 0.5 mol
• B. 1 mol
• C. 2 mol
• D. 3 mol

Hint:

Use $ n = \frac{\text{mass}}{\text{molar mass}} $ to calculate moles.

Answer 1

The Correct Option is B

Molar mass of $ \text{H}_2\text{O} = 2(1) + 16 = 18 \, \text{g/mol} $
Number of moles: $$ n = \frac{\text{Mass}}{\text{Molar Mass}} = \frac{18}{18} = 1 \, \text{mol} $$