1.5 mol of `O_(2)` combine with Mg to form oxide MgO. The mass of Mg (at mass 24) that has combined is

Options

A. 72g
B. 36g
C. 48g
D. 24g

Explanation

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

### Step 1: Write the balanced chemical equation
The balanced equation for the reaction between magnesium and oxygen is:
\[ 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} \]

### Step 2: Determine the mole ratio
From the balanced equation, we can see that 1 mole of O₂ reacts with 2 moles of Mg. Therefore, the mole ratio of O₂ to Mg is:
\[ 1 \text{ mol O}_2 : 2 \text{ mol Mg} \]

### Step 3: Calculate the moles of magnesium needed
Given that we have 1.5 moles of O₂, we can calculate the moles of magnesium required using the mole ratio:
\[ \text{Moles of Mg} = 1.5 \text{ mol O}_2 \times \frac{2 \text{ mol Mg}}{1 \text{ mol O}_2} = 3 \text{ mol Mg} \]

### Step 4: Calculate the mass of magnesium
Now, we need to find the mass of magnesium that corresponds to 3 moles. The molar mass of magnesium (Mg) is given as 24 g/mol. Therefore, the mass of magnesium can be calculated as:
\[ \text{Mass of Mg} = \text{Moles of Mg} \times \text{Molar mass of Mg} = 3 \text{ mol} \times 24 \text{ g/mol} = 72 \text{ g} \]

### Conclusion
The mass of magnesium that combines with 1.5 moles of O₂ to form magnesium oxide (MgO) is **72 grams**.

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