The percentage of oxygen in a compound is determined by

Options

A. Dumas method
B. Kjeldhl's method
C. Carius method
D. Subtraction the sum of percentage of all other elements present from 100.

Answer

To determine the percentage of oxygen in a compound, we can use the method of subtraction from the total percentage of all other elements present in the compound. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Compound**: Start with the chemical formula of the compound for which you want to find the percentage of oxygen. For example, let's consider carbon dioxide (CO2).

2. **Calculate the Total Molecular Mass**: Determine the molecular mass of the compound.
- For CO2:
- Carbon (C) has an atomic mass of approximately 12 g/mol.
- Oxygen (O) has an atomic mass of approximately 16 g/mol.
- Therefore, the molecular mass of CO2 = 12 + (2 × 16) = 12 + 32 = 44 g/mol.

3. **Determine the Mass of Oxygen in the Compound**: Identify the total mass contributed by oxygen in the compound.
- In CO2, there are 2 oxygen atoms, so the mass of oxygen = 2 × 16 = 32 g.

4. **Calculate the Percentage of Oxygen**: Use the formula for percentage:
\[ \text{Percentage of Oxygen} = \left( \frac{\text{Mass of Oxygen}}{\text{Molecular Mass of Compound}} \right) \times 100 \]
- For CO2:
\[ \text{Percentage of Oxygen} = \left( \frac{32}{44} \right) \times 100 \approx 72.73\% \]

5. **Conclusion**: The percentage of oxygen in the compound CO2 is approximately 72.73%.