Elemental analysis of a sample of an ionic compound showed 2.82 g of Na, 4.35 g of Cl, and 7.83 g of O. What is the empirical formula of the compound?

• A. NaClO
• B. NaClO₂
• C. NaClO₃
• D. NaClO₄

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by determining the number of moles of each element in the sample. Use the molar mass of each element to convert grams to moles. The molar mass of Na is approximately 22.99 g/mol, Cl is approximately 35.45 g/mol, and O is approximately 16.00 g/mol.
2. Step 2: Calculate the moles of sodium (Na) using the formula: \( \text{moles of Na} = \frac{2.82 \text{ g}}{22.99 \text{ g/mol}} \).
3. Step 3: Calculate the moles of chlorine (Cl) using the formula: \( \text{moles of Cl} = \frac{4.35 \text{ g}}{35.45 \text{ g/mol}} \).
4. Step 4: Calculate the moles of oxygen (O) using the formula: \( \text{moles of O} = \frac{7.83 \text{ g}}{16.00 \text{ g/mol}} \).
5. Step 5: Determine the simplest whole number ratio of moles of each element. Divide the moles of each element by the smallest number of moles calculated in the previous steps. This will give you the subscripts for the empirical formula.