The number of oxygen atoms present in 50 g of calcium carbonate is

Options

A. `6.023xx10^(23)`
B. `30.1xx10^(23)`
C. `9.035xx10^(23)`
D. `1.20xx10^(24)`

Answer

To find the number of oxygen atoms present in 50 g of calcium carbonate (CaCO₃), we can follow these steps:

### Step 1: Calculate the molar mass of calcium carbonate (CaCO₃)
- Atomic mass of Calcium (Ca) = 40 g/mol
- Atomic mass of Carbon (C) = 12 g/mol
- Atomic mass of Oxygen (O) = 16 g/mol

The molar mass of CaCO₃ is calculated as follows:
\[ \text{Molar mass of CaCO₃} = \text{mass of Ca} + \text{mass of C} + 3 \times \text{mass of O} \]
\[ = 40 + 12 + (3 \times 16) = 40 + 12 + 48 = 100 \text{ g/mol} \]

### Step 2: Calculate the number of moles of CaCO₃ in 50 g
Using the formula:
\[ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molar mass}} \]
\[ = \frac{50 \text{ g}}{100 \text{ g/mol}} = 0.5 \text{ moles} \]

### Step 3: Calculate the number of molecules of CaCO₃
Using Avogadro's number (approximately \(6.022 \times 10^{23}\) molecules/mol):
\[ \text{Number of molecules} = \text{Number of moles} \times \text{Avogadro's number} \]
\[ = 0.5 \text{ moles} \times 6.022 \times 10^{23} \text{ molecules/mol} = 3.011 \times 10^{23} \text{ molecules} \]

### Step 4: Calculate the number of oxygen atoms
Each molecule of CaCO₃ contains 3 oxygen atoms. Therefore, the total number of oxygen atoms is:
\[ \text{Total oxygen atoms} = \text{Number of molecules} \times 3 \]
\[ = 3.011 \times 10^{23} \text{ molecules} \times 3 = 9.033 \times 10^{23} \text{ oxygen atoms} \]

### Final Answer
The number of oxygen atoms present in 50 g of calcium carbonate is approximately \(9.033 \times 10^{23}\).

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