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PLS HELP STOICHIOMETRY/CHEM!!!

Determine the empirical formula of a compound containing 48.38 grams of carbon, 6.74 grams of hydrogen, and 53.5 grams of oxygen.
In an experiment, the molar mass of the compound was determined to be 180.15 g/mol. What is the molecular formula of the compound?
For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations. (10 points)

User Keithstric
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2 Answers

23 votes
23 votes

Final answer:

The empirical formula is CH₂O, obtained by converting the masses of carbon, hydrogen, and oxygen to their respective molar amounts and determining their simplest whole number ratio. The molecular formula is C₆H₁₂O₆ which is six times the empirical formula based on the molar mass of the compound.

Step-by-step explanation:

To determine the empirical formula of the compound, we first need to convert the gram amounts of each element to moles by using their respective atomic masses (C=12.01 g/mol, H=1.008 g/mol, O=16.00 g/mol):

  • C: 48.38 grams ÷ 12.01 g/mol = 4.028 moles
  • H: 6.74 grams ÷ 1.008 g/mol = 6.686 moles
  • O: 53.5 grams ÷ 16.00 g/mol = 3.344 moles

Next, we determine the simplest whole number ratio of the moles of each element by dividing each by the smallest number of moles out of the three:

C: 4.028 moles ÷ 3.344 moles = 1.204 (approximately 1)

H: 6.686 moles ÷ 3.344 moles = 1.999 (approximately 2)

O: 3.344 moles ÷ 3.344 moles = 1

This gives us the empirical formula CH₂O. To find the molecular formula, we divide the molar mass of the compound by the molar mass of the empirical formula (CH₂O = 30.03 g/mol):

Molar mass of compound / Molar mass of empirical formula = 180.15 g/mol ÷ 30.03 g/mol = 6

The molecular formula is six times the empirical formula: (CH₂O)6 or C₆H₁₂O₆.

User Demanzonderjas
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2.6k points
23 votes
23 votes

Answer:

The empirical formula is
COH_(2), and the molecular formula is
C_(6)O_(6)H_(12).

User Andriy Tolstoy
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3.0k points