Calculate the number of moles in 369 grams of ` CaOCl_2` ​

Options

A. 23
B. 3
C. 2
D. 1

Answer

To calculate the number of moles in 369 grams of \( \text{CaOCl}_2 \), follow these steps:

### Step 1: Determine the molecular mass of \( \text{CaOCl}_2 \)

1. **Identify the atomic masses:**
- Calcium (Ca) = 40 g/mol
- Oxygen (O) = 16 g/mol
- Chlorine (Cl) = 35.5 g/mol

2. **Calculate the molecular mass of \( \text{CaOCl}_2 \):**
- The formula \( \text{CaOCl}_2 \) consists of:
- 1 Calcium atom
- 1 Oxygen atom
- 2 Chlorine atoms
- Therefore, the molecular mass is calculated as follows:
\[ \text{Molecular mass} = (1 \times 40) + (1 \times 16) + (2 \times 35.5) \]
- Calculate:
\[ \text{Molecular mass} = 40 + 16 + 71 = 127 \text{ g/mol} \]

### Step 2: Use the formula to calculate the number of moles

3. **Use the formula for moles:**
\[ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molecular mass}} \]
- Given mass = 369 g
- Molecular mass = 127 g/mol

4. **Calculate the number of moles:**
\[ \text{Number of moles} = \frac{369}{127} \approx 2.91 \text{ moles} \]

### Step 3: Round to the nearest whole number if necessary

5. **Final result:**
- The number of moles is approximately 2.91, which can be rounded to 3 moles.

### Conclusion

The number of moles in 369 grams of \( \text{CaOCl}_2 \) is approximately **3 moles**.

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