Which of the following compounds has the largest mass percent of oxygen?

• A. CO2
• B. H2O
• C. H2O2
• D. C2H5OH

Answer: (C)

Verified step by step guidance

1. Identify the molecular formula of each compound: CO2 (carbon dioxide), H2O (water), H2O2 (hydrogen peroxide), and C2H5OH (ethanol).
2. Calculate the molar mass of each compound by summing the atomic masses of all atoms present. Use approximate atomic masses: C = 12 g/mol, H = 1 g/mol, O = 16 g/mol.
3. For each compound, calculate the total mass of oxygen atoms by multiplying the number of oxygen atoms by the atomic mass of oxygen (16 g/mol).
4. Determine the mass percent of oxygen in each compound using the formula: \(\text{Mass \% of O} = \left( \frac{\text{Mass of oxygen atoms}}{\text{Molar mass of compound}} \right) \times 100\%\).
5. Compare the mass percent of oxygen calculated for each compound to identify which one has the largest value.