A sample of calcium carbonate `(CaCO_(3))` has the following percentage composition:
`Ca=40%,C=12%,O=48%`
If the law of constant proportions is true, then the weight off calcium in 4g of a sample of calcium carbonate from another source will be

Options

A. 0.016 g
B. 0.16 g
C. 1.6 g
D. 16 g

Answer

To solve the problem, we need to calculate the weight of calcium in a 4g sample of calcium carbonate (CaCO₃) based on its percentage composition.

### Step-by-Step Solution:

1. **Understand the Composition**:
- The percentage composition of calcium carbonate (CaCO₃) is given as:
- Calcium (Ca) = 40%
- Carbon (C) = 12%
- Oxygen (O) = 48%

2. **Apply the Law of Constant Proportions**:
- According to the law of constant proportions, the composition of a compound remains constant regardless of its source. Therefore, in any sample of calcium carbonate, the percentage of calcium will always be 40%.

3. **Calculate the Weight of Calcium in 4g of CaCO₃**:
- To find the weight of calcium in a 4g sample, we can use the percentage of calcium:
\[ \text{Weight of Calcium} = \left(\frac{\text{Percentage of Calcium}}{100}\right) \times \text{Total Weight of Sample} \]
- Substituting the values:
\[ \text{Weight of Calcium} = \left(\frac{40}{100}\right) \times 4g \]
\[ \text{Weight of Calcium} = 0.4 \times 4g = 1.6g \]

4. **Conclusion**:
- The weight of calcium in the 4g sample of calcium carbonate is **1.6 grams**.