1.5 mol of `O_(2)` combine with Mg to form MgO. The mol of Mg that has combined is

Explanation

To solve the problem of how many moles of magnesium (Mg) combine with 1.5 moles of oxygen (O₂) to form magnesium oxide (MgO), we can follow these steps:

### Step-by-Step Solution:

1. **Write the Balanced Chemical Equation**:
The reaction between magnesium and oxygen can be represented by the equation:
\[ 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} \]
This equation shows that 2 moles of magnesium react with 1 mole of oxygen.

2. **Identify the Mole Ratio**:
From the balanced equation, we see the mole ratio of O₂ to Mg is 1:2. This means that for every 1 mole of O₂, 2 moles of Mg are required.

3. **Calculate Moles of Mg for 1.5 Moles of O₂**:
If 1 mole of O₂ requires 2 moles of Mg, then 1.5 moles of O₂ will require:
\[ \text{Moles of Mg} = 1.5 \, \text{moles of O}_2 \times \frac{2 \, \text{moles of Mg}}{1 \, \text{mole of O}_2} = 3 \, \text{moles of Mg} \]

4. **Conclusion**:
Therefore, the amount of magnesium that has combined with 1.5 moles of oxygen is 3 moles.

### Final Answer:
The moles of magnesium that have combined is **3 moles**.

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