1. BALANCING EQUATIONS & CHEMICAL REACTIONS

2. Evidence of Chemical Change Changes in Energy (E) Release of E as heat Release of E as light Production of sound Reduction or increase of temperature Absorption or release of electrical Energy Formation of new substances Formation of a gas Formation of a precipitate Change in color Change in odor

3. Conservation of Mass Law of Conservation of Mass In any physical or chemical reaction, mass is neither created nor destroyed; it is conserved! Reactants Products Same number of atoms on both sides of the equation!

4. Balancing Equations In every balanced equation each side of the equation has the same number of atoms of each element

5. Vocab Terms Subscripts – tells how many atoms of each element you have NH 3 (one nitrogen, three hydrogen)- DON’T mess with these!! Coefficients – small whole number that appears in front of a chemical formula in an equation – you get to “mess” with these. 2NH 3 (Two molecules of ammonia or two moles of ammonia)  the arrow means yields or reacts to produce

6. REACTANTS PRODUCTS You have to get the same number of elements on each side of the reaction

7. Balancing Rules 1. Never touch subscripts when balancing equations, you will change the substance 2. Include all sources of the element CH 3 CHOOH + NaOH 3. Polyatomic ions that appear intact on both sides of the equation, can be balanced as a group (PO 4 ) 4. Coefficients in your balanced equation contain the lowest possible ratio.

8. Balancing! Aluminum + Oxygen  Aluminum Oxide Al + O 2  Al 2 O 3 Until you get good at this, it is helpful to write the number of atoms of each element on both sides of the equation. It helps you to keep track of the atoms.

9. Balancing! Ethene + Oxygen  Carbon Dioxide + water C 2 H 4 + O 2  CO 2 + H 2 O

10. Balancing! Hydrogen gas + nitrogen gas  ammonia Remember your diatomic molecules!!!

11. Try this one! NaNO 3 + CrCl 3  NaCl + Cr(NO 3 ) 3

12. Balance this equation… NaNO 3 + CrCl 3  NaCl + Cr(NO 3 ) 3 Write the word equation.

13. Important stuff! Four abbreviations are used to indicate physical states of chemicals: shown as subscripts in the chemical equation (s) = solid (l) = liquid (g) = gas (aq)= aqueous solution ( dissolved in water) Symbols over the arrow indicate the conditions of the reaction Heat Pressure Temperature Catalyst Reversible reaction

14. Why does it happen? Use the file to make four hash marks perpendicular to the face of the penny. Carefully drop the penny into the 6M HCl solution.

15. Check out the Pennys! Make some qualitative observations about the pennies. (Look at the dates- remember what you learned at the beginning of the year in the Penny Density Lab) As we proceed: You may want to write these down! 1. What kind of reaction 2. Write and balance the chemical equation. 3. Explain your observations. 4. What kind of quantitative observations would be helpful?

16. Warm Up- A sample contains a compound with 3.60 g of carbon and 0.61 g of hydrogen. The molar mass of the compound is 42.09g/mol. Determine the formula of the compound. Remind me to pass back your EMP Formula Packets. I only graded a few- answers are posted on line.

17. Wonder Projects- HONORS ONLY Go to my website

18. REACTIONS

19. Combination Reaction or Synthesis Reaction Two or more simple substances react to form a more complicated one A + B  AB Fe + S  FeS

21. Combination Reactions We can predict the products of ionic compounds by thinking about the charge! Ga (s) + O 2 (g)  Cu (s) +S (s)  Are there 2 possible products to the 2nd reaction? How would we “say” these equations?

22. Decomposition Reaction A decomposition reaction is the opposite of a composition reaction - a complex molecule breaks down to make simpler ones. AB  A + B 2 H 2 O  2 H 2 + O 2

24. Decomposition Reactions Harder to predict the products…always remember your diatomics. Water is often a product! HgO (s)  NH 4 NO 3  CaCO 3  (Carbonates usually decompose to CO 2 )

25. Decomposition Reactions HgO (s)  2HgO (s)  2Hg (l) + O 2 (g) NH 4 NO 3  NH 4 NO 3  N 2 O+2H 2 O CaCO 3  CaO + CO 2 The only way to really know is to do the reaction!!

26. Warm Up Predict the products of the following reactions. 1. H 2 O 2  1. Mg + N 

27. Warm Up Predict the products of the following reactions. 1. H 2 O 2  We heat the dihydrogen dioxide and the vapor turns out to be water… 2. Mg + N  Mg 3 N 2

28. How are you doing on the Word Equation WS?

29. Single Replacement This is when one element trades places with another element in a compound. A + BC  AC + B Mg + 2H 2 O 

31. Single Replacement Reactions Easy to predict the products. Look at the ions… remember that a cation has to bond to an anion!! Don’t forget about diatomics! Zn (s) +H 2 SO 4(aq)  Na (s) +H 2 O  OOPS! Did we balance them?

32. Single Replacement Reactions Zn (s) +H 2 SO 4(aq)  Zn (s) +H 2 SO 4(aq)  ZnSO 4(aq) + H 2(g) Na (s) +H 2 O  Na (s) +H + OH - (l)  2Na (s) +2H + OH - (l)  2NaOH + H 2(g)

33. Single Replacement Reactions Reactivity of a metal makes a difference! If a metal is more reactive than the metal it is displacing a rxn will occur. If the metal is less reactive than the metal it is displacing, a rxn will not occur.

34. Metal Reactivity Increases down a group Decreases across a period

35. Brainiacs-- Metal Reactivity

36. Reactivity in Single Displacement Cs + KMnO 4  CsMnO 4 + K Will this occur?? Na + KMnO 4  NaMnO 4 + K Will this occur?

37. Double Replacement Reaction This is when the anions and cations of two different molecules switch places, forming two entirely different compounds AB + CD  AD + CB Pb(NO 3 ) 2 + 2KI  PbI 2 + 2KNO 3

39. Double Replacement Reactions Two ionic compounds in aqueous solution Generally 3 things happen: 1. A precipitate (solid) occurs Pb(NO 3 ) 2 + 2KI  PbI 2 + 2KNO 3

40. Double Replacement Reactions 2. One product is a gas that bubbles out of the mixture 2NaCN (aq) + H 2 SO 4  2HCN (g) + Na 2 SO 4(aq)

41. Double Replacement Reactions 3. One product is a molecule while the other products remain ions Ca(OH) 2(aq) + 2HCl (aq)  Ca +2 + Cl - + 2 H 2 O (l )

42. Warm Up- Determine the type of reaction and predict the products. 1. Al + Br 2  2. FeO + Na  3. SnCl 4  4. NaNO 3 + CaCO 3 

43. Combustion Reactions A combustion reaction is when oxygen combines with another compound or element producing energy. When hydrocarbons (C ? H ? ) combust, water, carbon dioxide and energy are produced. C 10 H 8 + O 2  CO 2 + H 2 O + Energy Can you balance it? Combustion of Naphthalene

44. Combustion Reactions Combustion of propane: C 3 H 8 + O 2  Combustion of methane: CH 4 +O 2  Combustion of butene (this one is tricky!) C 4 H 6 + O 2 

45. Teacher Demo Extraordinaire!

46. What is a flame video- Science Friday http://www.sciencefriday.com/video/06/08/2012/ what-is-a-flame.html

47. Combustion Analysis Problems… Honors Only So, we can collect the water vapor and the carbon dioxide…. do some calculations…. and determine the empirical formula of the hydrocarbon. C ? H ? + O 2  CO 2 + H 2 O 11.56g 2.36g

48. Start the Types of Reactions Lab 1. Spend about 5 minutes on the Background. 2. Read through the procedure at each station. 3. You need to get at least 3 of the 6 stations finished today. 4. Goggles must be worn at all times. 5. Listen carefully for safety concerns while I intro the labs.

49. Predict the products, balance and classify the following reactions. Li + MgCl 2  C 6 H 12 + O 2  Ca(NO 3 ) 2 + NaOH 

50. Warm Up- Friday Balance the following equations: C 3 H 6 + O 2  CO 2 + H 2 O C 7 H 14 + O 2  CO 2 + H 2 O

51. Finish Types of Rxns Lab

52. What do the equations mean? The coefficients indicate the number of moles of the reactants necessary… to form a certain mole of the product. Mole to Mole Ratio 3K + AlCl 3  Al + 3KCl