3.2 gm of Mg (At. mass 24) will produce MgO equal to:

Options

A. 0.2mole
B. 0.13 mole
C. 3 mole
D. 4mole

Explanation

To solve the problem of how much MgO is produced from 3.2 grams of magnesium (Mg), we can follow these steps:

### Step 1: Write the balanced chemical equation
The reaction for the formation of magnesium oxide (MgO) from magnesium and oxygen is as follows:

\[ \text{2 Mg} + \text{O}_2 \rightarrow \text{2 MgO} \]

This equation indicates that 2 moles of magnesium react with 1 mole of oxygen to produce 2 moles of magnesium oxide.

### Step 2: Calculate the number of moles of magnesium
To find out how many moles of magnesium are in 3.2 grams, we use the formula:

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

Given:
- Mass of Mg = 3.2 g
- Molar mass of Mg = 24 g/mol

Calculating the number of moles of Mg:

\[ \text{Number of moles of Mg} = \frac{3.2 \, \text{g}}{24 \, \text{g/mol}} = 0.1333 \, \text{mol} \approx 0.13 \, \text{mol} \]

### Step 3: Determine the number of moles of MgO produced
From the balanced equation, we see that 2 moles of Mg produce 2 moles of MgO. Therefore, the number of moles of MgO produced will be equal to the number of moles of Mg used:

\[ \text{Number of moles of MgO} = \text{Number of moles of Mg} = 0.13 \, \text{mol} \]

### Step 4: Calculate the mass of MgO produced
Now, we can calculate the mass of MgO produced using its molar mass. The molar mass of MgO is:

\[ \text{Molar mass of MgO} = \text{Molar mass of Mg} + \text{Molar mass of O} = 24 \, \text{g/mol} + 16 \, \text{g/mol} = 40 \, \text{g/mol} \]

Now, we can find the mass of MgO produced:

\[ \text{Mass of MgO} = \text{Number of moles of MgO} \times \text{Molar mass of MgO} \]

\[ \text{Mass of MgO} = 0.13 \, \text{mol} \times 40 \, \text{g/mol} = 5.2 \, \text{g} \]

### Final Answer
The mass of MgO produced from 3.2 grams of magnesium is **5.2 grams**.

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