1. THE MOLE

2. STANDARDS Use the mole concept to determine the number of particles and mass in a chemical compound. (includes gram to mole to atom conversions) Determine molar mass, percent composition, empirical formulas, and molecular formulas. (includes hydrates)

3. Atomic Mass Unit Location on the periodic table unit

4. Terms Molecular mass Formula mass

6. Calculating average atomic mass Not all isotopes of an element will be present in the same amount.

7. SAMPLE PROBLEM Neon has 2 isotopes. Neon- 20 has a mass of 19.992 u and neon – 22 has a mass of 21.991u. In an average sample of 100 atoms, 90 will be neon 20 and 10 will be neon –22. Calculate the average atomic mass.

8. SAMPLE PROBLEM Two isotopes of the same element have the following: 1 st isotope 6.015 u 7.5% abundance 2 nd isotope 7.016 u 92.5% Calculate the atomic mass of the unknown element and determine the elements identify.

9. Determining molecular/formula mass

10. Mole Standard unit for large numbers of atoms, ions, or molecules Mol one mole of particles has a mass in grams equivalent to that of one particle in atomic mass units can be referred to as a gram molecular weight

11. Avogadro Constant 6.02 x 10 23

12. Molar mass The mass of one mole of atoms, ions, formula units

13. Gram/Mol/Atom conversions

14. Percent composition Represents the relative mass each element contributes to the mass of the compound as a whole used to identify unknown compounds sample problem –Find the percent composition of aluminum sulfate. It is used in water treatment plants to purify water.

15. Empirical Formulas Shows the simple whole number ratio can be determined from percent composition sample problem – Determine the empirical formula for a compound is a 2.50 gram sample contains 0.9g of Ca and 1.6 g of chlorine

16. Empirical Formula from percent composition Sample problem –A compound has a percent composition of 40.0%carbon, 6.71% hydrogen, and 53.3% oxygen. What is its empirical formula?

17. Problems Sometimes dividing by the smallest number of moles does not yield a ratio close to a whole number. There are no fractions. Atoms must exist as a whole sample problem –What is the empirical formula of a compound that is 66.0% calcium and 34.0% phosphorus

18. Determining molecular formula form empirical formula Sample problem –Find the molecular formulas of a substance that has an empirical formulas of AgCo 2 and a formula mass of 394u.

19. Hydrates Compounds that crystallize from a water solution with water molecules adhering to the ions or molecules and becoming part of the crystal contain a specific ratio of water molecules water is loosely bonded heat drives water off - crystal collapses

20. Hydrates continued Naming hydrates/ writing hydrates hydrate calculations sample problem –We have a 10.407 sample of hydrated barium iodide. The sample is heated to drive off the water. The dry sample has a mass of 9.520g. What is the mole ratio between barium iodide and water. What is the hydrate formula?