Question

give the chemical formula,molar mass,and % compostionn of the following problems.round to the nearest 10
iron(III)sulfide

Answer 1

**Iron(III) sulfide** has the chemical formula \( \text{Fe}_2\text{S}_3 \).

### Molar Mass Calculation:
- Atomic mass of Iron (Fe) ≈ 55.85 g/mol
- Atomic mass of Sulfur (S) ≈ 32.07 g/mol

Calculating the molar mass:

\[
\text{Molar mass of } \text{Fe}_2\text{S}_3 = (2 \times 55.85) + (3 \times 32.07)
\]

\[
= 111.70 + 96.21 = 207.91 \, \text{g/mol}
\]

### Percentage Composition:

- **% Composition of Iron (Fe)**:

\[
\text{% Fe} = \left( \frac{2 \times 55.85}{207.91} \right) \times 100 \approx \left( \frac{111.70}{207.91} \right) \times 100 \approx 53.7\%
\]

- **% Composition of Sulfur (S)**:

\[
\text{% S} = \left( \frac{3 \times 32.07}{207.91} \right) \times 100 \approx \left( \frac{96.21}{207.91} \right) \times 100 \approx 46.3\%
\]

### Summary:
- **Chemical Formula**: \( \text{Fe}_2\text{S}_3 \)
- **Molar Mass**: 208 g/mol (rounded to the nearest 10)
- **% Composition**:
- Iron (Fe): 54% (rounded to the nearest 10)
- Sulfur (S): 46% (rounded to the nearest 10)