What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?
Practice Questions
1 question
Q1
What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?
CH2O
C2H4O2
C3H6O3
C4H8O4
Convert percentages to grams (assume 100 g total): 40 g C, 6.7 g H, 53.3 g O. Convert to moles: C=3.33, H=6.67, O=3.33. The simplest ratio is 1:2:1, giving CH2O.
Questions & Step-by-step Solutions
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Q
Q: What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?
Solution: Convert percentages to grams (assume 100 g total): 40 g C, 6.7 g H, 53.3 g O. Convert to moles: C=3.33, H=6.67, O=3.33. The simplest ratio is 1:2:1, giving CH2O.
Steps: 10
Step 1: Assume you have 100 grams of the compound. This makes it easy to convert percentages to grams.
Step 2: Convert the percentages to grams: 40% carbon means 40 grams of carbon (C), 6.7% hydrogen means 6.7 grams of hydrogen (H), and 53.3% oxygen means 53.3 grams of oxygen (O).
Step 3: Calculate the number of moles for each element using their atomic masses: Carbon (C) has an atomic mass of about 12 g/mol, Hydrogen (H) is about 1 g/mol, and Oxygen (O) is about 16 g/mol.
Step 4: For Carbon: 40 grams C ÷ 12 g/mol = 3.33 moles of C.
Step 5: For Hydrogen: 6.7 grams H ÷ 1 g/mol = 6.7 moles of H.
Step 6: For Oxygen: 53.3 grams O ÷ 16 g/mol = 3.33 moles of O.
Step 7: Now, you have the moles: C = 3.33, H = 6.7, O = 3.33.
Step 8: Find the simplest ratio of moles by dividing each by the smallest number of moles (which is 3.33).
