1. 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 C 3 H 6 and C 5 H 10 have in common?

2. 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.

3. 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 C 6 H 12 O 6. –Its empirical formula is CH 2 O. The subscripts in a chemical formula represent a MOLE ratio of elements in the compound.

4. 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.

5. 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.

6. Independent Practice Determine the empirical formula of each of the followings compounds if a sample contains a)0.104 mol K, 0.052 mol C, and 0.156 mol O b)5.28 g Sn and 3.37 g F c)36.8% N and 63.2% O

7. Wrapping It Up Reflect on what you have learned concerning the today’s 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?