Which of the following compounds has the same empirical formula as its molecular formula?

• A. C_6H_{12}O_6
• B. C_4H_{10}
• C. C_2H_4
• D. H_2O

Answer: (D)

Verified step by step guidance

1. Understand the difference between empirical and molecular formulas: The empirical formula represents the simplest whole-number ratio of atoms in a compound, while the molecular formula shows the actual number of atoms of each element in a molecule.
2. For each compound, determine the ratio of atoms and simplify it to the smallest whole numbers to find the empirical formula.
3. Compare the empirical formula to the molecular formula for each compound. If they are the same, then the compound's molecular formula is already in its simplest form.
4. For example, water (H_2O) has 2 hydrogen atoms and 1 oxygen atom, and this ratio cannot be simplified further, so its empirical formula is the same as its molecular formula.
5. Check the other compounds: glucose (C_6H_{12}O_6) simplifies to CH_2O, but the molecular formula is not the same as the empirical formula; similarly, C_4H_{10} simplifies to C_2H_5, and C_2H_4 simplifies to CH_2, so their molecular and empirical formulas differ.