1. Unit 13:CHEMICAL REACTIONS Reactants: Zn + I2 Product: Zn I2

4. Law of conservation of mass and energy.

6. Law of conservation of mass and energy.

7. Write and balance chemical equations.

9. Substances can be Atoms, Molecules, or CompoundsReactants Products Chemical reaction is occurring

11. Substances can be Atoms, Molecules, or Compounds

12. Reactants are the things being brought together to react

13. Products are the new stuff that is made in the reaction!Reactants Products Chemical reaction is occurring

14. Identifying chemical reactions The release of heat and/or light The formation of a solid when two liquids are mixed together (precipitate)

15. Identifying chemical reactions The change in color when two liquids are poured together The formation of a gas from a liquid solution

16. Chemical Equations Because of the principle of the conservation of matter The chemical equation must be balanced It must have the same number of atoms of the same kind on both sides. C3H8 + O2 CO2 + H2O C = 3 H = 8 O =2 C = 1 H = 2 O = 3

17. Balancing Equations C3H8 + O2 CO2 + H2O 3C 8H C3H8 + O2 CO2 + H2O

18. Balancing Equations C3H8 + O2 CO2 + H2O C3H8 + O23CO2 + 4H2O 10 O = 6 O + 4 O

19. Balancing Equations C3H8 + O2 CO2 + H2O C3H8 + O23CO2 + 4H2O 10 O

20. Balancing Equations C3H8 + O2 CO2 + H2O C3H8 + 5O23CO2 + 4H2O 10 O

21. Which one of the following is a balanced equation? Ca (s) + O2 (g) -> 2CaO (s) B. 2Ca (s) + O2 (g) -> 2CaO (s) C. 3Ca (s) + O2 (g) -> CaO (s) D. 6Ca (s) + O2 (g) -> 2CaO (s) Secret Question

22. Which one of the following is a balanced equation? Ca (s) + O2 (g) -> 2CaO (s) B. 2Ca (s) + O2 (g) -> 2CaO (s) C. 3Ca (s) + O2 (g) -> CaO (s) D. 6Ca (s) + O2 (g) -> 2CaO (s) Secret Question

23. Which one of the following is a balanced equation? Ca (s) + O2 (g) -> 2CaO (s) B. 2Ca (s) + O2 (g) -> 2CaO (s) C. 3Ca (s) + O2 (g) -> CaO (s) D. 6Ca (s) + O2 (g) -> 2CaO (s) 2O 2Ca and 2O 2Ca Secret Question

24. Symbols Used in Equations Solid (s) Liquid (l) Gas (g) Aqueous solution (aq) Catalyst H2SO4 Change of temperature () Delta

25. Chemical Equations Reactants and Products Al (s) + O2 (g) ---> Al2O3 (s) Stoichiometry:

26. Chemical Equations Reactants and Products Al (s) + O2 (g) ---> Al2O3 (s) Stoichiometry: 2Al 2

27. Chemical Equations Reactants and Products Al (s) + O2 (g) ---> Al2O3 (s) Stoichiometry: 3O 2 times what equals 3?

28. Chemical Equations Reactants and Products Al (s) + O2 (g) ---> Al2O3 (s) Stoichiometry: 3O 2 times what equals 3? 1.5 but, that is not a whole number… So, what do we do?

29. Chemical Equations Reactants and Products Al (s) + O2 (g) ---> 2Al2O3 (s) Stoichiometry: 6O 2 times what equals 6?

30. Chemical Equations Reactants and Products Al (s) + 3O2 (g) ---> 2Al2O3 (s) Stoichiometry: 6O 2 times what equals 6?

31. Chemical Equations Reactants and Products Al (s) + 3O2 (g) ---> 2Al2O3 (s) Stoichiometry: 4Al 2 times what equals 6?

32. Chemical Equations Reactants and Products 4Al (s) + 3O2 (g) ---> 2Al2O3 (s) Stoichiometry: is the part of chemistry that studies amounts of substances that are involved in reactions.

33. Chemical Equations Fe2O3 = rust Aluminum powder What happens when you mix rust and aluminum? Thermite Reaction

34. Chemical Equations Fe2O3 + 2Al -> 2Fe + Al2O3 Thermite Reaction http://www.youtube.com/watch?v=sjLgzgflCk8&feature=related

35. Chemical Equations Fe2O3 + 2Al -> 2Fe + Al2O3 Thermite Reaction This reaction needs a lot of heat to get started, but produces far more heat afterwards (> 2000°F)

36. Classifying Reactions Five main types: Synthesis Combustion Decomposition Single displacement Double displacement

37. Synthesis Reaction Two or more substances combine to form another substance. For example: A + B  AB 2H2+ O2 2H2O 2 or more simpler substances  one more complex substance

38. Decomposition Reactions Opposite of synthesis. One substance breaks down into 2 or more other substances. AB  A + B One compound 2 or more simpler substances 2H2O 2H2+ O2 electricity

39. Single Replacement Reaction One element replaces another element in a compound A + BC  AC + B Element + compound  new element + new compound Zn + CuSO4  ZnSO4 + Cu

40. Double Replacement Reactions Positive ion of one compound replaces the positive ion of the other AB + CD  AD + CB 2 compounds 2 new compounds Forms precipitate, covalent compound, or gas AgNO3 (aq) + NaCl (aq) -> AgCl (s) + NaNO3 (aq)

41. Combustion Reaction of a substance with oxygen and a flame If it is combustion of a hydrocarbon, you always get CO2 and H2O (both gases) Oxygen (O2) is always a reactant. C3H8 + 5 O2 -> 3 CO2 + 4 H2O + heat