1. MOLAR MASS Video 2.1

2. Stoichiometry  The Mole represents a specific amount of any substance.  Specifically it represents 6.02x10 23 particles such as atoms and molecules.

3. The Mole = 6.02x10 23  The mole is based on the fact that 12 grams of Carbon-12 has a mole of atoms.  A mole means you have 6.02x10 23 particles.

4. Molar Mass  Molar Mass (aka gram formula mass or molecular mass) is the mass of one mole of a substance.  Element’s molar masses are reported on the periodic table.

5. Molar Mass Examples: Elements 1. What is the molar mass of iron? 2. What is the molar mass of copper? 55.8 g/mol 63.5 g/mol

6. Molar Mass Examples: Compounds 1.What is the molar mass of water? H2O = 2(1.0) + 16.0 = 18.0g/mol 2.What is the gram-formula-mass of calcium chloride? CaCl2 = 40.1 + 2(35.5) = 111.1 g/mol

7. MOLES Video 2.2

8. What if you have more than one mole of a substance? Use the formula on table T: number of moles = given mass (g) _ gram-formula mass (Given mass will be your answer.)

9. Let’s try these together… 1. Calculate the mass of 6.70 moles of carbon. 6.70 = x _ 12.og/mol x = 80.4 g

10. Example 2 Calculate the mass of 0.023moles of lithium. 0.023 = x _ 6.9 g/mol x = 0.16 g

11. Example 3 Calculate the mass of 25.02 moles of calcium phosphate. 25.02 = x _ 310.3/mol x = 7764 g

12. The gfm formula  Use the same formula to calculate the moles, placing the number in the question on the numerator: number of moles = given mass (g) gram-formula mass

13. Let’s try these together… 4. Determine the number of moles in 8.0 grams of Boron. x = 8.0 g _ 10.8g/mol x = 0.74 moles

14. Example 5 Determine the number of moles in 0.567 grams of Helium. x = 0.567 g _ 4.00 g/mol x = 0.142 moles

15. Example 6 Find the number of moles in 1230 grams of magnesium sulfate. x = 1230 g _ 120.4 g/mol x = 10.2 moles

16. BALANCING Video 2.3

17. Conservation of Mass  In a reaction, atoms and molecules cannot appear or disappear. Mass must stay constant from the beginning to the end of the reaction.  H 2 + O 2  H 2 O  ___H 2 + ___O 2  ___ H 2 O 22 1

18. Balancing Reactions ___ N 2 + ____H 2  ____ NH 3 ___Li + ____O 2  ___Li 2 O 2 3 2 4

19. Balancing __Pb(NO 3 ) 2 +__K 2 CrO 4  ___PbCr 2 O 4 + ___KNO 3 ___C 4 H 8 + ___O 2  ___CO 2 + ___H 2 O 2 44 5

20. Types of Reactions 1. Synthesis: A + 2B  AB 2 2. Decomposition: AB 2  A + 2B 3. Combustion: CH 4 + O 2  CO 2 + H 2 O 4. Single Replacement:AB + C  CB +A 5. Double Replacement:AB + CD  AD + CB * Notice synthesis and decomposition are opposites. Also, combustion can have any carbon compound as a reactant.

21. FORMULAS Video 2.4

22. Empirical Formulas  Empirical formula refers to any molecular formula in it’s reduced form. Are these empirical? If not, reduce them: 1. C 2 H 2 2. C 6 H 12 O 6 3. NO 2 4. Na 2 (OH) 2 1.CH 2.CH 2 O 3.NO 2 4.NaOH

23. Molecular Formulas  Molecular Formulas are some multiple of the empirical formula.  If the empirical formula is CH 4 a molecular formula could be CH 4, C 2 H 8, C 3 H 12 etc.  A compound whose empirical formula is NH 3 has a mass of 34 g/mol. What is the empirical formula? NH 3 = 17.0 g/mol 34/17 = 2 2NH 3 = N 2 H 6

24. Steps:  Find the mass of the empirical formula.  Divide the mass given by the empirical mass.  Distribute your answer through the empirical formula.  If a compound has a mass of 45 g/mol and an empirical formula of CH 3, what is the molecular formula? CH 3 = 15 g/mol 45/15 = 3 3CH 3 = C 3 H 9

25. NAMING Video 2.5

26. What is the difference between an element and a compound?

27. Definitions  Elements cannot be broken down by physical or chemical changes.  Compounds are composed of 2 or more elements that can be broken down by chemical change.  What type of matter can be broken down by physical changes?

28. Ions Ions are elements with a charge. The reference table lists these charges for each element. If the element is positive, it is called a cation. Cations are named the same as the element. (Example: Ca=Calcium atom / Ca +2 =Calcium ion) If the element in negative, it is called an anion. Anions are named ending with “-ide” (Example: N=Nitrogen atom / N -3 = Nitride ion)

29. You try: Mg +2 K + O -2 F - Li + I -

30. Binary Compounds Binary Compounds consist of only two of elements. To name: write the complete name of the first element. The second element should then be named, ending in “-ide.” NaClsodium chloride KIpotassium iodide MgCl 2 Ca 3 N 2 magnesium chloride calcium nitride

31. You try… Li 3 P Al 2 S 3 SrBr 2 Rb 2 O BaSe CsI

32. Criss-cross Rule To write a formula, write the two ions separately showing their charges. Charges are on the periodic table. Then, swap the two numbers and drop the sign: Calcium nitride:Ca 2+ N -3 Ca 3 N 2 Lithium oxide:Li + O -2 Li 2 O Notice, we don’t write ones!

33. Problem:  FeCl 2 and FeCl 3 are different compounds but seem to have the same name. How can we name them different?  FeCl 2 is iron (II) chloride FeCl 3 is iron (III) chloride.  What do the roman numerals represent?

34. Transition Metals and Nonmetals Transition Metals are in the middle group of the periodic table. Nonmetals are on the right side of the staircase. They have multiple charges or oxidation numbers and so you must show which charge you are using with roman numerals: I II III IV V VI VII

35. Try these… FeCl 2 CuF ZnO N 2 O 3 SO 4 PCl 3 CH 4

36. Careful: This rule doesn’t ALWAYS work for cations. Find the anion’s charge and equalize that with the cation’s charge as a check.

37. Try these… Potassium iodide Magnesium chloride Aluminum sulfide Hydrogen oxide Barium selenide Cesium phosphide Strontium phosphide Copper (II) flouride Iron (III) telluride KI MgCl2 Al2S3 H2O BaSe Ce3P Sr3P2 CuF2 Fe2Te3