Given that the empirical formula is HO and the molar mass is 34.02 g/mol, what is the molecular formula of the compound?

• A. HO
• B. H2O4
• C. H2O2
• D. H2O

Answer: (C)

Verified step by step guidance

1. Determine the molar mass of the empirical formula HO by adding the atomic masses of hydrogen (H) and oxygen (O). Use the atomic masses: H = 1.01 g/mol, O = 16.00 g/mol. Calculate the empirical formula mass as \$1.01 + 16.00$ g/mol.
2. Calculate the ratio of the molar mass of the compound to the empirical formula mass using the formula: \(\text{ratio} = \frac{\text{molar mass of compound}}{\text{empirical formula mass}}\).
3. Determine the integer multiple (n) by rounding the ratio to the nearest whole number. This integer tells you how many empirical units are in the molecular formula.
4. Multiply the subscripts in the empirical formula by the integer n to find the molecular formula. For example, if the empirical formula is HO and n = 2, the molecular formula will be \(\mathrm{H}_{2}\mathrm{O}_{2}\).
5. Write the molecular formula clearly, confirming that its molar mass matches the given molar mass when calculated.