Chemistry

Question Analysis
This question tests the student's ability to determine the empirical formula from the percent composition of a compound.

Key Concept Explanation
The empirical formula is derived by converting the percent composition to moles, finding the mole ratio, and then simplifying to the smallest whole-number ratio.

Step-by-step Solution
1. Assume a 100 g sample: C: 45.0 g, H: 5.0 g, O: 50.0 g.
2. Convert grams to moles: C: 45.0 g / 12.01 g/mol ≈ 3.75 mol, H: 5.0 g / 1.008 g/mol ≈ 4.96 mol, O: 50.0 g / 16.00 g/mol = 3.125 mol.
3. Find the mole ratio: C: 3.75 / 3.125 = 1.20, H: 4.96 / 3.125 ≈ 1.60, O: 3.125 / 3.125 = 1.00.
4. Convert to whole numbers:
The ratios (1.2, 1.6, 1) are not whole numbers.
Multiply all by 5 to eliminate decimals:
C:
H: