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

Options

A. (a)72 g
B. (b)36 g
C. (c )48 g
D. (d)24 g

Explanation

To find the mass of magnesium (Mg) that combines 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 as:
\[ 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} \]
This indicates that 2 moles of magnesium react with 1 mole of oxygen.

2. **Determine the ratio of magnesium to oxygen:**
From the balanced equation, we see that:
- 2 moles of Mg react with 1 mole of O₂.
- Therefore, 1 mole of O₂ will react with 2 moles of Mg.

3. **Calculate the moles of magnesium needed for 1.5 moles of O₂:**
Using the ratio from the balanced equation:
\[ \text{Moles of Mg} = 2 \times \text{Moles of O}_2 \]
Substituting the value:
\[ \text{Moles of Mg} = 2 \times 1.5 = 3 \text{ moles of Mg} \]

4. **Calculate the mass of magnesium:**
The atomic mass of magnesium (Mg) is given as 24 g/mol. To find the mass of 3 moles of magnesium:
\[ \text{Mass of Mg} = \text{Moles of Mg} \times \text{Atomic Mass of Mg} \]
Substituting the values:
\[ \text{Mass of Mg} = 3 \text{ moles} \times 24 \text{ g/mol} = 72 \text{ grams} \]

### Final Answer:
The mass of magnesium that has combined is **72 grams**.

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