1. © 2005 Mark S. Davis AP CHEMISTRY Chapter 3

2. © 2005 Mark S. Davis Law of Conservation of Mass Mass is neither created nor destroyed in chemical reactions –Lavoisier

3. © 2005 Mark S. Davis Chemical equations Tell you: –What has –What –Ratio of –Products, reactants –Conditions

4. © 2005 Mark S. Davis Generally Reactants  Products Coefficients

5. © 2005 Mark S. Davis Symbols (s) (l) (g) (aq)  +

6. © 2005 Mark S. Davis Example Carbon is burned in air to form carbon dioxide

7. © 2005 Mark S. Davis Example Carbon is burned in air to form carbon monoxide 22

8. © 2005 Mark S. Davis Balancing equations Why? –To show conservation of mass –Keep proper amounts of reactants and products –Show proper ratios between products and reactants

9. © 2005 Mark S. Davis Example C 2 H 6 + O 2  CO 2 + H 2 O

10. © 2005 Mark S. Davis Patterns of reactivity Groups are similar in reactivity Alkali metals

11. © 2005 Mark S. Davis Types of reactions Combustion Synthesis (Combination) Decomposition Single Replacement Double Replacement

12. © 2005 Mark S. Davis Combustion Reaction

13. © 2005 Mark S. Davis Combustion Occurs in air

14. © 2005 Mark S. Davis Combustion Reactions Fuel – Carbon compound Ignition source – flame Oxygen source

15. © 2005 Mark S. Davis Synthesis Reaction Reaction of two substances to form one product Either elements or compounds react to form one compound as product Generally:

16. © 2005 Mark S. Davis Example Mg + O 2  MgO Sodium reacts with Chlorine

17. © 2005 Mark S. Davis Decomposition Reaction One compound breaks apart to form two or more other elements or compounds. Generally: Sodium azide

18. © 2005 Mark S. Davis Airbags

19. © 2005 Mark S. Davis Example NaN 3(s)  Na (s) + N 2(g) Sugar is decomposed to form carbon and water

20. © 2005 Mark S. Davis Single Replacement Reaction of an element and a compound to form two new substances Generally: Zinc and Copper sulfate

21. © 2005 Mark S. Davis Example Zn (s) + CuSO 4(aq) 

22. © 2005 Mark S. Davis Solubility Rules In the book… table 4.1 p 111 Also posted online.

23. © 2005 Mark S. Davis Double Replacement Two solutions react to form two or more new substances Generally: Lead (II) nitrate and potassium iodide Identify the solid, gas, liquid, aqueous components

24. © 2005 Mark S. Davis Example Pb(NO 3 ) 2(aq) + KI (aq)

25. © 2005 Mark S. Davis http://dbhs.wvusd.k12.ca.us/webdoc s/ChemTeamIndex.htmlhttp://dbhs.wvusd.k12.ca.us/webdoc s/ChemTeamIndex.html http://dbhs.wvusd.k12.ca.us/webdoc s/Equations/Equations.htmlhttp://dbhs.wvusd.k12.ca.us/webdoc s/Equations/Equations.html

26. © 2005 Mark S. Davis Atomic Weights The weight of an atom of an element

27. © 2005 Mark S. Davis Average Atomic Mass Average mass of all the isotopes of an element –98.5% C-12 –1.5% C-13

28. © 2005 Mark S. Davis Formula Weight The sum of the masses of all the atoms in a compound. Usually refers to – –

29. © 2005 Mark S. Davis Molecular Weight The weight of all the atoms in a – –

30. © 2005 Mark S. Davis The MOLE Quantity of a substance

31. © 2005 Mark S. Davis Molar Mass The mass in grams of one mole of a substance – –

32. © 2005 Mark S. Davis Avogadro’s Number The number of particles in one mole of a compound 6.022 x 10 23 particles in one mole

33. © 2005 Mark S. Davis Conversions

34. © 2005 Mark S. Davis Empirical Formulas Simplest formula C 6 H 12 O 6 can be reduced to Represents the

35. © 2005 Mark S. Davis Empirical Formulas Ethylene glycol, the substance used in automobile antifreeze, is composed of 38.7% C, 9.7% H, and 51.6% O by mass. Its molar mass is 62.1 g/mol. What is the empirical formula? What is the molecular formula?

36. © 2005 Mark S. Davis Empirical Formulas Caproic acid, which is responsible for the foul odor of dirty socks, is composed of C, H, O. Combustion of 0.225 g of caproic acid produces 0.512 g CO 2 and 0.209 g H 2 O. What is the empirical formula of caproic acid? If it has a molar mass of 116 g/mol, what is the molecular formula?

37. © 2005 Mark S. Davis Problem Determine the empirical formula of a compound that has the composition of 20.20 % magnesium, 26.60 % sulfur, 53.20 % oxygen.

38. © 2005 Mark S. Davis Problem 2 It was determined that a compound was made from 43.66 % P and 56.34 % O, what is the empirical formula?

39. © 2005 Mark S. Davis Molecular Formulas Represents the formula of the actual molecule If the empirical formula is CH 2 O and the molar mass is 120 amu, what is the molecular formula?

40. © 2005 Mark S. Davis Early Stoichiometry Stoichiometry Steps for success online Method of converting

41. © 2005 Mark S. Davis Limiting Reactants

42. © 2005 Mark S. Davis Theoretical Yield