1.  Update your Table of Contents  Write your homework – leave it to be stamped  Get a marker from the blue basket and get ready to grade your test also!  Get your Adopt-An-Element Baby Book out, but DO NOT turn it in yet…we are going to grade it! WARM – UP: DateSession # ActivityPage # 10/16 10/17 19 Law of Conservation of Mass Notes & Lab 32

2. Physical & Chemical changes can change matter, BUT…THE REAL QUESTION IS: During those changes, is any matter created or destroyed?

3. Law of Conservation of Mass/Matter Law of Conservation of Mass/Matter- Matter cannot be created or destroyed, it can only change form. So where does the wood go?

4. NaF NaF IN OTHER WORDS… What goes in, must come out!

5.  The container in which the reaction is performed is open - matter may escape Open System/Reaction

6.  The container in which the reaction is being performed is closed so all of the matter will be contained – nothing escapes Closed System/Reaction

7.  Watch the dry ice demo  Write ANY observations!  Explain how this demonstrates The Law of Conservation of Mass! Dry Ice Demo

8.  Freezing Point of Carbon Dioxide = -108.4 o F or -78 o C  Boiling Point of Carbon Dioxide = -76 o F or -57 o C  Formula: Is this physical or chemical? CO 2 (s) CO 2 (g) Dry Ice Demo Dry Ice = Solid Carbon Dioxide

9. Law of Conservation of Mass (Matter) Lab Investigation Roles  Group Leader – Reading and making sure the group is following directions accurately and completing all parts of the lab  Supply Manager – Gets, returns & cleans supplies  Measurement Technician – gets and returns the scale balance and is responsible for accurate mass measurements  Data Discussion Technician – makes sure the group records the mass data before and after the experiment, AND everyone has an explanation for THE TEACHER DEMO, STUDENT LAB & COMPARE & CONTRAST  ONE LAB GUIDE WILL BE PICKED FOR THE GROUP GRADE

10. Law of Conservation of Mass (Matter) Lab Investigation  Send your supply manager to get the lab kit and your measurement technician to get the scale balance.  Group leader, read the directions carefully each step of the way!! ◦ WARNING: YOUR BALLOON IS ALREADY FULL OF BAKING SODA, DO NOT TIP IT INTO THE GRADUATED CYLINDER ACCIDENTALLY!

11. Law of Conservation of Mass (Matter) Lab Investigation Clean-Up  Balloons in the garbage  Rinse graduated cylinder thoroughly  Wipe up any spills  Put all items back into your lab kit & put them on the front counter  Put scale balance back onto the back counter  Make sure every group member has measurements and ALL parts of the lab guide are complete

12.  Again, the explanation should state how BOTH experiments demonstrated the Law of Conservation of Mass…BUT, what were the similarities and differences between them? Compare & Contrast

13.  Update your Table of Contents  Write your homework – leave it to be stamped  What does the Law of Conservation of Mass/Matter state? WARM – UP: DateSession # ActivityPage # 10/20 10/21 20 Balancing Act Note Guide 33 Balancing Equations Practice 34

14. What does the Law of Conservation of Mass/Matter state?

15. NaF NaF REMEMBER: What goes in, must come out!

16. Chemical Reactions Reactants – Elements OR compounds present at the beginning of a chemical reaction Product – Compounds formed by a chemical reaction

17. REACTANTSREACTANTS PRODUCTPRODUCT

18. Balancing Chemical Equations  Since matter can neither be created or destroyed, the mass/amount of reactants must always equal the mass/amount of products

19. Balancing Chemical Equations  Before (Reactants)  After (Product) Na F = 1 NaF Na = 1 F F = 1

20. NaF NaF The arrow indicates that a change has occurred

21. 2H 2 + O 2 2H 2 O  (Reactants)(Products) Chemical formulas for elements Chemical formula for new compound Subscripts Coefficient Subscript

22. What is that little number? Subscript – ◦ Shows how many atoms of an element are in a compound. ◦ When there is NO subscript there is only 1 atom of that element. O2O2 NH 4 NaClK5N4C2K5N4C2

23. What is that big number in front? Coefficient – ◦ The number of molecules (compounds) involved in a chemical reaction H2H2 H2H2 O2O2 H2H2 O2O2 H2OH2O 2 2

24. So the coefficient tells you the number of molecules, but what about each atom?  You must multiply…it is like the distributive property in math! 2NH 4 5H 2 O 2Li 3 F 2 4NaCl2K 5 N 4 C 2 3O 2

25. Rules for Balancing Chemical Equations 1. You CANNOT change subscripts, you can ONLY change coefficients H 2 + O 2 2H 2 O 2. It does NOT have to look the same on both sides, it only has to be balanced 3. You CANNOT split compounds to write in a coefficient: HCl

26. Rules to Balancing Chemical Equations 4. Only multiply through when it is a compound because they have already bonded 2H + Cl 2HCl NOYES 5. If it is a capital letter, they are each a separate element: H, C, O If it is a capital letter followed by a lower case letter, it is all one element: Cl, Li, Si

27. Steps for Balancing Chemical Equations  1. Divide the reactants from the products with a line.  2. Write down the chemical symbol of each of the elements on each side of the equation 2 H 2 + O 2 2H 2 O H = O = H = O =

28. Steps to Balancing Chemical Equations  3. Using the coefficients and subscripts write down the number of each element  4. If they are not balanced change the coefficients using trial and error. You will have to go back and forth between each side! 2 H 2 + O 2 2H 2 O H = 4 O = 2 H = 4 O = 2

29. Lets Practice P + O 2 P4O6P4O6

30. Lets Practice Na + O 2 Na 2 O

31. Lets Practice Al 2 O 3 Al + O 2

32. Lets Practice Cl 2 + KIKCl + I 2

34.  Update your Table of Contents  Write your homework – leave it to be stamped  Complete the Warm-Up side of the note guide WARM – UP: DateSession # ActivityPage # 10/22 - 10/23 21 Endothermic Reactions Vs. Exothermic Reactions 35

35. Law of Conservation of Mass (Matter) Law of Conservation of Mass (Matter)- Matter cannot be created or destroyed, it can only change form In other words… What goes in, must come out!

36. Law of Conservation of Mass (Matter) Analyzing Reactions  Some chemical reactions are ENDOTHERMIC = take “in” or absorb energy  Some chemical reactions are EXOTHERMIC = give “out” or produce energy How would you tell the difference?

37. Endothermic Reactions  An endothermic reaction takes “in” or absorbs energy  Causes temperature around it to cool (will feel cold)  EXAMPLE: Photosynthesis (needs energy from the sun)

38.  An exothermic reaction gives “out” or produces energy (heat, light or sound)  Causes temperature around it to rise (feels warm/hot)  EXAMPLE: cellular respiration (gives energy to your cells) Exothermic Reactions

39. Endo & Exo Lab Investigation Roles  Group Leader – Responsible for reading and making sure the group is following directions accurately  Supply Manager – gets and returns supplies and makes sure they are clean  Data Discussion Technician – makes sure the group records all observations and has an explanation for BOTH investigations!  Speaker – Group member that must share your explanation/conclusion with the class.

40. REVIEW  BALANCING EQUATIONS…Please get your Rules & Steps for balancing equations out!

41. Rules for Balancing Chemical Equations 1. You CANNOT change subscripts, ONLY coefficients H 2 + O 2 2H 2 O 2. It does NOT have to look the same on both sides, it only has to be balanced 3. You CANNOT split compounds to write in a coefficient: HCl

42. Rules to Balancing Chemical Equations 4. Only multiply through when it is a compound because they have already bonded 2H + Cl 2HCl NOYES 5. If it is a capital letter, they are each a separate element: H, C, O If it is a capital letter followed by a lower case letter, it is all one element: Cl, Li, Si

43. Steps for Balancing Chemical Equations  1. Divide the reactants from the products with a line.  2. Write down the chemical symbol of each of the elements on each side of the equation 2 H 2 + O 2 2H 2 O H = O = H = O =

44. Steps to Balancing Chemical Equations  3. Using the coefficients and subscripts write down the number of each element  4. If they are not balanced change the coefficients using trial and error. You will have to go back and forth between each side! 2 H 2 + O 2 2H 2 O H = 4 O = 2 H = 4 O = 2

45. Last Chance to Balance  Balance the 5 equations on the sheet – if you get them correct you will be using the Chromebooks for the remainder of class to complete the “Study Buddy Review”  If you get them incorrect you will move up to the front counter with me practicing how to balance equations.

46. REVIEW  Play the review games listed on the sheet on top of the Chromebook cart.  You may play with a partner if the game requires 2 players.  If you get through all of them ONLY then can you search for alternate CHEMISTRY RELATED sites/games!!

47. EXPECTATIONS  I expect you and your partner to play only what you are supposed to without being disruptive in any way so that I can focus on helping the people who need it!!  When you are working with me you are expected to complete the equations!!

48. P + OP 4 O 10 Equation 1 - Balance Box Answer

49. Cl ₂ + NaBr NaCl + Br ₂ Equation 2 - Balance Box Answer

50. Cs + N ₂ Cs 3 N Equation 3 - Balance Box Answer

51. CuCl ₂ + H ₂ S CuS + HCl Equation 4 - Balance Box Answer

52. Al + HCl AlCl ₃ + H ₂ Equation 5 - Balance Box Answer

53. Balancing Equations Practice Homework  Find the Balancing Equations Practice Homework or take another sheet – we will work on a few together, and then you can practice on your own.

54. Na + MgF 2 Lets Practice: Part D - #1 NaF + Mg

55. Cl 2 + KI Lets Practice: Part D - #2 KCl + I 2 IMPORTANT: Cl = Chlorine K & I are 2 separate elements

56. HCl + NaOH Lets Practice: Part D - #3 NaCl + H 2 O

57. Na + NaNO 3 Lets Practice: Part D - #4 Na 2 O + N 2

58. PbBr 2 + HCl Lets Practice: Part D - #5 HBr + PbCl 2

59.  Try 6, 7 & 8 on your own, and then check the answer key REVIEW

60. Na 3 P + CaF 2 Lets Practice: Part D - #6 NaF + Ca 3 P 2

61. AlBr 3 + K Lets Practice: Part D - #7 KBr + Al

62. CaF 2 + Li 2 SO 4 Lets Practice: Part D - #8 CaSO 4 + LiF