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

Options

A. 0.4mol
B. 0.05mol
C. 40g
D. 5mol

Explanation

To solve the problem of how much MgO is produced from 1.2 grams of Mg, we will follow these steps:

### Step 1: Write the chemical reaction
The reaction between magnesium (Mg) and oxygen (O2) to form magnesium oxide (MgO) can be represented as:
\[ 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} \]

### Step 2: Calculate the number of moles of Mg
To find the number of moles of magnesium, we use the formula:
\[ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molar mass}} \]
Given:
- Mass of Mg = 1.2 g
- Molar mass of Mg = 24 g/mol

Now, substituting the values:
\[ \text{Number of moles of Mg} = \frac{1.2 \text{ g}}{24 \text{ g/mol}} = 0.05 \text{ moles} \]

### Step 3: Determine the moles of MgO produced
From the balanced equation, we can see that 1 mole of Mg produces 1 mole of MgO. Therefore, the number of moles of MgO produced will be equal to the number of moles of Mg reacted:
\[ \text{Number of moles of MgO} = 0.05 \text{ moles} \]

### Step 4: Calculate the mass of MgO produced
To find the mass of MgO produced, we first need to calculate the molar mass of MgO:
- Molar mass of Mg = 24 g/mol
- Molar mass of O = 16 g/mol
- Therefore, molar mass of MgO = 24 + 16 = 40 g/mol

Now, we can calculate the mass of MgO produced using the formula:
\[ \text{Mass} = \text{Number of moles} \times \text{Molar mass} \]
Substituting the values:
\[ \text{Mass of MgO} = 0.05 \text{ moles} \times 40 \text{ g/mol} = 2 \text{ g} \]

### Conclusion
Thus, 1.2 grams of Mg will produce 2 grams of MgO.

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