Warm up:

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Warm up

1. A compound consists of potassium and oxygen.
   What is the formula for this compound?
2. A sample of a compound is found to contain 6.35 g
   iron and 3.65 g sulfur . Express the amount of
   each element in terms of moles.
3. Other than they contain the same elements, what
   do the compounds C3H6 and C5H10 have in common?

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Determining the Empirical Formula of a Compound

• If we know how much of each element is present in
  a compound, we can determine the formula of the
  compound.
• Amounts may be expressed in
• percentages
• grams
• moles
• If composition is given in terms of percentages,
  assume you have a 100 g sample of the
  compound, so percentages grams.

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• From this data, the empirical formula can be
  determined.
• The empirical formula or simple formula is a
  formula in which the elements are in their lowest
  whole number ratio.
• The empirical formula may or may not be the
  actual formula.
• Example
• The formula for glucose is C6H12O6 .
• Its empirical formula is CH2O.
• The subscripts in a chemical formula represent a
  MOLE ratio of elements in the compound.

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DETERMINING THE EMIRICAL FORMULA OF A COMPOUND

• Example 1
• Analysis shows a compound consists of 32.4 Na,
  22.6 S, and 45.0 O. Determine the empirical
  formula for this compound.

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DETERMINING THE EMIRICAL FORMULA OF A COMPOUND

• Example 2
• A compound is found to contain 4.43 g phosphorus
  and 5.72 g oxygen. Find the empirical formula
  for this compound.

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Independent Practice

• Determine the empirical formula of each of the
  followings compounds if a sample contains
• 0.104 mol K, 0.052 mol C, and 0.156 mol O
• 5.28 g Sn and 3.37 g F
• 36.8 N and 63.2 O

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Wrapping It Up

• Reflect on what you have learned concerning the
  todays topic.
• Respond to the following
• What are the three most important things you
  learned today?
• What is one question you would still like
  answered?
• What is the one way what you have learned
  connects with what you knew before?