2. How many moles are in 36.0 g of water \( \left(\mathrm{H}_{2} \mathrm{O}\right) \) ? A. 1.0 moles B. 0.5 moles C. 2.0 moles D. 6.0 moles

To determine the number of moles in 36.0 grams of water (\(\mathrm{H}_2\mathrm{O}\)), you can use the following formula: \[ \text{Number of moles} = \frac{\text{Mass (g)}}{\text{Molar Mass (g/mol)}} \] **Step 1: Calculate the Molar Mass of Water (\(\mathrm{H}_2\mathrm{O}\))** - **Hydrogen (H):** There are 2 hydrogen atoms in each water molecule. - Atomic mass of H ≈ 1.008 g/mol - Total for hydrogen: \(2 \times 1.008 \, \text{g/mol} = 2.016 \, \text{g/mol}\) - **Oxygen (O):** There is 1 oxygen atom in each water molecule. - Atomic mass of O ≈ 16.00 g/mol - **Total Molar Mass of \(\mathrm{H}_2\mathrm{O}\):** \[ 2.016 \, \text{g/mol (H)} + 16.00 \, \text{g/mol (O)} = 18.016 \, \text{g/mol} \] **Step 2: Calculate the Number of Moles** \[ \text{Number of moles} = \frac{36.0 \, \text{g}}{18.016 \, \text{g/mol}} \approx 2.0 \, \text{moles} \] **Answer:** **C. 2.0 moles**