A compound is found to be 66.6% carbon and 33.4% hydrogen by mass. What is the empirical formula of this compound?

• A. C3H8
• B. CH
• C. C2H4
• D. CH2

Answer: (D)

Verified step by step guidance

1. Step 1: Assume you have 100 grams of the compound. This means you have 66.6 grams of carbon (C) and 33.4 grams of hydrogen (H).
2. Step 2: Convert the masses of each element to moles by dividing by their atomic masses: use 12.01 g/mol for carbon and 1.008 g/mol for hydrogen. Calculate moles of C as \(\frac{66.6}{12.01}\) and moles of H as \(\frac{33.4}{1.008}\).
3. Step 3: Determine the simplest whole number mole ratio by dividing both mole values by the smaller number of moles obtained in Step 2.
4. Step 4: If the mole ratio is not a whole number, multiply both ratios by the smallest factor that converts them into whole numbers (e.g., 2, 3, 4, etc.).
5. Step 5: Write the empirical formula using the whole number mole ratios as subscripts for carbon and hydrogen atoms, respectively.