1. Chemical Reactions

2. Today you are going to…take notes on chemical reactions. So you can…interpret, write, and balance chemical equations You’ll know you’ve got it when you can Differentiate between chemical & physical changes Identify the parts of a chemical equation Define, explain, and give examples of precipitates & catalysts

3. Physical change –a change in the appearance of something, often easier to “undo” – Ex. Chemical change – a substance changes into a new substances with new properties (and new chemical formulas). – Ex.

4. Chemical Reactions Word Equation – to express the change in words. Chemical equation – to express the change in formulas.

5. The parts of a chemical equation CH 4 + 2 O 2  CO 2 + 2 H 2 O

6. The parts of a chemical equation Reactants – chemicals reacting Products – chemicals produced Coefficients – big numbers, used to balance equation, how many of each compound/molecule Subscripts – part of chemical formula, tells how many of each atom is in chemical Yields – arrow! CH 4 + 2 O 2  CO 2 + 2 H 2 O

7. Word Eq: Water yields hydrogen gas and oxygen gas. Chem. Eq: Word Eq: In the presence of a nickel catalyst, solid calcium chloride reacts with gaseous carbon dioxide to form solid calcium oxide and gaseous dicarbon trichloride.* (don’t balance) Chem. Eq:

8. States of Matter in Equations Liquid water decomposes into hydrogen gas and oxygen gas. (s) - solid (l) - liquid (g) - gas (aq) – aqueous solution (dissolved in water) 2 H 2 0 (l)  2 H 2 (g) + O 2 (g)

9. Precipitate A solid produced by mixing two aqueous solutions – A precipitate video. ID products, reactants, ect.precipitate Lead (II) nitrate in solution reacts with sodium iodide in solution to form lead (II) iodide precipitate and a sodium nitrate solution.

10. Precipitate You get gold & precious metals from computers via precipitates!

11. Carbon monoxide gas mixes with oxygen gas to make carbon dioxide gas. 2 CO (g) + O 2 (g)  2 CO 2 (g) 1.Write a chemical equation for the reaction above. 2.Define catalyst 3.Write the chemical formula of the products & reactants above. 4.What does aqueous mean? 5.Define precipitate 6.Why do equations have to be balanced? (why & what law) Pt

12. 2CO (g) + O 2 (g)  2CO 2 (g) 1.In presence of a platinum catalyst, gaseous carbon monoxide combines with gaseous oxygen to form gaseous carbon dioxide. 2.A catalyst is something that speeds up or slows down a chemical reaction without chemically changing itself. 3.Reactants are CO & O 2 Product is CO 2 4.Aqueous means “dissolved in water” 5.A precipitate is the solid formed from a reaction between 2 aqueous solutions. 6.Equations have to be balanced to be physically accurate/true. If they’re not balanced, they show matter either magically appearing or disappearing, which can’t happen. The law of conservation of mass states that matter cannot be created nor destroyed. Pt

13. Catalysts A substance that changes the rate of a chemical reaction without being consumed or changed significantly – Positive catalysts - speed up reaction Lower the amount of energy required to activate the reaction – Negative catalysts, aka “inhibitors” - slow down reaction Uses – Used in making gasoline, plastics, margarine, beer – In laundry detergents – In living things - enzymes are biological catalysts

14. Examples of Catalysts Platinum in catalytic convert reduces NO emissions In presence of a platinum catalyst, nitrogen monoxide gas decomposes into nitrogen gas and oxygen gas 2NO (g)  N 2 (g) + O 2 (g) Platinum decreases CO emissions 2CO (g) + O 2 (g)  2CO 2 (g) Pt

15. What’s the word equation? In presence of sulfuric acid catalyst, ethanol gas reacts with hydrochloric acid gas to form chloroethane and liquid water In the presence of a vanadium (V) oxide catalyst, sulfur dioxide gas reacts with oxygen gas to produce sulfur trioxide gas.

16. Reactants being heated ∆ means the reactants are heated

17. 1.Write equation 2.Add a nickel catalyst to the equation 3.Formulas of products? 4.Subscripts? 5.Coefficients?

18. Liquid HCl

19. Schedule 4 th & 7 th Wednesday – Mythbusters – Update Grades Thursday – Notes on writing equations – HW Chem Eq Wkst (quiz Monday) Friday – Review HW – Elephant toothpaste! Monday – Quiz – Finish elephant toothpaste – Types of chem reactions – Balancing Equations Tuesday – Review quiz – Balance more equations! Wednesday – Balance Equations computer lab

20. Elephant Toothpaste Elephant toothpaste demos!demos – H 2 O 2 liquid hydrogen peroxide – KI – Food coloring – Dish soap – Drop lots of matches in! Drop them horizontal or with flame side up and they look cooler as they’ll sit there a while.

21. Elephant Toothpaste Elephant toothpaste demos!demos 2 H 2 O 2 (aq) → O 2 (g) + 2 H 2 O(l) KI

22. Bell Work 2/11/14 – 5 min N 2 (g) + O 2 (g)  N 2 O 5 (l) 1.Write the word equation for the above reaction. 2.What is the reason for balancing equations? 3.What is the big difference between a physical & chemical change? (In a chemical change…) Ni

23. Today you are going to…take notes on chemical reactions. So you can…classify and balance chemical equations. You’ll know you’ve got it when you can State the Law of Conservation of Mass. Identify & describe the 5 types of reactions. Balance chemical equations.

24. 6 Types of Chemical Reactions Synthesis Decomposition Single-Displacement Double-Displacement Acid-Base Combustion

25. Synthesis What does synthesis mean? Synthetic? Two or more substances combine to form one. A + B ---> AB One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide: Fe + S 8 ---> FeS

26. Decomposition What does decompose mean? One complex substance breaks down to make 2 simpler ones. (Opposite of synthesis) AB ---> A + B Ex: Electrolysis of water to make oxygen and hydrogen gas: H 2 O ---> H 2 + O 2

27. Single-Displacement What does single mean? What does displacement mean? One element trades places with another element in a compound. A + BC ---> AC + B Ex: when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas: Mg + Be(OH) 2 ---> Mg(OH) 2 + Be

28. Cu + 2AgNO 3 ---> Cu(NO 3 ) 2 + 2Ag Make sure it’s in a clear clean glass, small enough you can easily see through it. Try pennies of different years

29. Double-Displacement The parts of two substances switch places, forming two new substances. AB + CD ---> AD + CB Ex: the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate: Pb(NO 3 ) 2 + 2 KI ---> PbI 2 + 2 K(NO 3 )

30. Acid-Base A double displacement reaction that takes place when an acid and base react with each other. Makes water (& usually salt). HA + BOH ---> H 2 O + BA Ex: hydrobromic acid reacts with sodium hydroxide HBr + NaOH ---> H 2 O + NaBr

31. Give students something Can you turn this into water?

32. Candle demo! Pass out candles and jars and ask the groups to make observations...see if they can come to conclusion. So what gases were in the jar? 2 O 2 + CH 4  CO 2 + 2 H 2 O – Limiting reactant! – Why do we balance equations? – Jar of alcohol?

33. Combustion What does combustion mean? When oxygen combines with another compound (hydrocarbon) to form water and carbon dioxide. These reactions are exothermic, meaning they __________________. Ex: Burning of napthalene: C 10 H 8 (s) + 12 O 2 (g)  10 CO 2 (g) + 4 H 2 O (g)

34. Combustion Candle demo – Limiting reactant! – Why do we balance equations? – Jar of alcohol? Bubble Soapy hand – Evaporation! Lycopodium powder

36. Bell Ringer – 2/12/14 3 Li (s) + AlCl 3 (l)  3 LiCl (aq) + Al (g) 1.In your notes, write the word equation for the chemical reaction above.

37. Bell Ringer – 2/12/12 3 Li (s) + AlCl 3 (l)  3 LiCl (aq) + Al (g) Solid lithium combined with liquid aluminum chloride yields aqueous lithium chloride and gaseous aluminum.

38. Schedule Monday – Review HW – Balancing equations practice/notes Tuesday – Balancing Equations Wednesday – Balance equations: computer lab Thursday – Review computer lab – More balancing equations practice – Preview Precipitate lab Friday – Precipitate Lab Monday – Review Precipitate lab – Demos! – Review for test Tuesday – Review for test Wednesday – Test

39. Law of Conservation of Mass Hotdogs & buns example! 8 hotdogs & 10 buns (Don’t want any extra.)

40. C 10 H 8 + 12 O 2  10 CO 2 + 4 H 2 O ++ 

41. Make this with a stick & ball H 2 0  H 2 + O 2

42. Law of Conservation of Mass Matter cannot be created nor destroyed by ordinary chemical or physical means. Things can’t just appear from nowhere, nor can they cease to exist. There have to be the same number of each atom on both sides of an equation. This is why you have to balance equations.

43. 1) synthesis – you make only 1 product Example – burning a piece of magnesium ribbon to make magnesium oxide. 2) decomposition –one reactant that breaks into 2 or more. Example – heating copper II carbonate to make copper II oxide and carbon dioxide. 3) Single displacement – an element replaces an element in a compound. Singles on both sides! Example - Adding a metal to an acid to make a metal chloride and hydrogen gas. 4) Double displacement – two elements switch places. (compounds on both sides) Example – any precipitate reaction 5) Combustion - hydrocarbon & oxygen produce carbon dioxide & water

44. Identify the type of reaction 1.H 2 + 2 O 2  2 H 2 O 2.C 10 H 8 + 12 O 2  10 CO 2 + 4 H 2 O 3.CO  C + O 2 4.Li + AlCl 3  LiCl + Al 5. B 2 Br 6 + H(NO 3 )  B(NO 3 ) 3 + HBr 6.H 2 + O 2  H 2 O 2 7.4 NH 3 + 3 O 2  2 N 2 + 6 H 2 O

45. How many of each atom are there? CsOH___________________ Na 2 SO 4 ___________________ (CO 3 ) 3 ___________________ Al 2 (SO 4 ) 3 ___________________ Ca(C 2 H 3 O 2 ) 2 ___________________ 2 Mg 3 P 2 ___________________ 3 Na 2 SO 4 ___________________ 2 Ca(C 2 H 3 O 2 ) 2 ___________________

46. Rules for balancing equations. NEVER CHANGE SUBSCRIPTS! Only change __________. Don’t give up…be persistent! 1.Polyatomic ion rule – if you have a polyatomic ion on both sides of the arrow, put parenthesis around it. 2.First Even/odd rule – if there’s an even number of atoms on one side and an odd number on the other side, multiply the odd number by 2. 3.Identify elements that appear in only one reactant and one product, and balance the atoms of those elements first. 4.Next balance the element with the greatest difference. 5.Lastly balance lone elements!

47. C 10 H 8 + 12 O 2  10 CO 2 + 4 H 2 O ++ 

48. Eq type? What rule applies? K + B 2 O 3  K 2 O + B

49. Eq type? What rule applies? Rb + S 8  Rb 2 S

50. Practice! Ag 2 S  Ag + S 8

51. Bell Work 4/28 – Balance these 1. SiCl 4 + H 2 O  SiO 2 + HCl 2. NH 3 + O 2  N 2 + H 2 O

52. Eq type? What rule applies? Na + H 2 O  NaOH + H 2

53. What rule applies? FeS 2 + O 2  Fe 2 O 3 + SO 2

54. Practice! Need practice problem

55. What rule applies? H 3 PO 4 + Ca(OH) 2  Ca 3 (PO 4 ) 2 + H 2 O

56. Practice! Need practice problem

57. What rule applies? H 3 PO 4 + KOH  K 3 PO 4 + H 2 O

58. C 2 H 6 + O 2  CO 2 + H 2 O

59. Al(OH) 3 + H 2 CO 3  Al 2 (CO 3 ) 3 + H 2 O

60. Bell Work: ID & Balance 1.H 2 + O 2  H 2 O 2.C 10 H 8 + O 2  CO 2 + H 2 O 3.CO  C + O 2 4.Li + AlCl 3  LiCl + Al 5.H 2 + O 2  H 2 O 2 6. NH 3 + O 2  N 2 + H 2 O 7. B 2 Br 6 + H(NO 3 )  B(NO 3 ) 3 + HBr

61. ID & Balance 1.H 2 + O 2  H 2 O 2.C 10 H 8 + O 2  CO 2 + H 2 O 3.CO  C + O 2

62. ID & Balance 1.H 2 + O 2  H 2 O 2.C 10 H 8 + O 2  CO 2 + H 2 O 3.CO  C + O 2 4.Li + AlCl 3  LiCl + Al 5.H 2 + O 2  H 2 O 2 6. NH 3 + O 2  N 2 + H 2 O 7. B 2 Br 6 + H(NO 3 )  B(NO 3 ) 3 + HBr

63. 1.2 H 2 + O 2  2 H 2 O 2.C 10 H 8 + 12 O 2  10 CO 2 + 4 H 2 O 3.2 CO  2 C + O 2 4.3 Li + AlCl 3  3 LiCl + Al

64. 1.H 2 + 2 O 2  2 H 2 O 2.C 10 H 8 + 12 O 2  10 CO 2 + 4 H 2 O 3.CO  C + O 2 4.Li + AlCl 3  LiCl + Al 5.H 2 + O 2  H 2 O 2 6.4 NH 3 + 3 O 2  2 N 2 + 6 H 2 O 7.B 2 Br 6 + 6 H(NO 3 )  2 B(NO 3 ) 3 + 6 HBr

65. END