Question

How to calculate the moles of magnesium and oxygen given their masses?

Answer 1

To calculate the number of moles of magnesium and oxygen from their masses, you can use the formula:

\[
\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}
\]

**Step 1: Find the Molar Masses**
- **Magnesium (Mg):** The molar mass of magnesium is approximately 24.31 g/mol.
- **Oxygen (O):** The molar mass of oxygen is approximately 16.00 g/mol.

**Step 2: Measure the Masses**
- Determine the mass of magnesium you have (let's say it's \( m_{Mg} \) grams).
- Determine the mass of oxygen you have (let's say it's \( m_{O} \) grams).

**Step 3: Calculate Moles**
- **Moles of Magnesium:**
\[
\text{moles of Mg} = \frac{m_{Mg}}{24.31 \, \text{g/mol}}
\]

- **Moles of Oxygen:**
\[
\text{moles of O} = \frac{m_{O}}{16.00 \, \text{g/mol}}
\]

**Example Calculation:**
1. If you have 48.62 g of magnesium:
\[
\text{moles of Mg} = \frac{48.62 \, \text{g}}{24.31 \, \text{g/mol}} \approx 2.00 \, \text{moles}
\]

2. If you have 32.00 g of oxygen:
\[
\text{moles of O} = \frac{32.00 \, \text{g}}{16.00 \, \text{g/mol}} = 2.00 \, \text{moles}
\]

Now you have the moles of magnesium and oxygen calculated based on their masses.