UNIT 5. Chemical Equations

Transcription

1 UNIT 5 Chemical Equations

2 Do Now Monday Determine the chemical formula of the following: 1. Calcium Oxide 2. Aluminum Sulfide 3. Diphosphorus tetraoxide

3 Announcements / Reminders Today Begin Unit 5, Homework #9 due Tomorrow Lab Activity Friday Notebook Quiz Next week: Monday Homework #10 due Tuesday Unit 5 Quiz 1 Friday Unit 5 Exam

4 Homework #10 Due Monday, 3/28 Use your World of Chemistry textbook to complete the following: pg #1 3 pg #5 8 pg # problems

5 Learning Target SWBAT summarize the law of conservation of mass and evidence of a chemical reaction Importance?

6 What is the Law of Conservation of Mass? Matter can never be created nor destroyed Total mass of reactants always equals the total mass of the products

7 What is a chemical reaction? Atoms rearrange and create a new substance There is always some observable evidence that a chemical reaction has occurred Examples: Bubbles form Precipitate forms Color changes An odor is produced Energy changes

8 Evidence of Chemical Reactions Bubbles form: Indicates a gas has been produced Common mistake: Could mean that the substance is boiling Phase changes ARE NOT chemical reactions

9 Evidence of Chemical Reactions Precipitate forms: An insoluble solid is created Common mistake: Dissolve substance has fallen out of solution

10 Evidence of Chemical Reactions Color change: A change in color MAY indicate a chemical reaction Common mistake: A color change can also indicate a physical change

11 Evidence of Chemical Reactions Odor produced: An odor may be released Common mistake: Odors may also be released if a substance undergoes a physical change

12 Evidence of Chemical Reactions Energy change: There is ALWAYS some sort of energy change in a chemical reaction Two types: Endothermic Exothermic

13 Evidence of Chemical Reactions Energy change: Exothermic heat is released Ex means out Area surrounding the reaction becomes warmer due to heat that is released

14 Evidence of Chemical Reactions Energy change: Endothermic heat is absorbed En means in Area surrounding the reaction becomes cooler due to heat that is absorbed

15 Evidence of Chemical Reactions Big idea: A combination of different pieces of evidence can indicate that a chemical reaction occurred

16 Law of C. of Mass: Demo As you watch, take notes on the following: 1. What question is being answered? 2. HOW is the question being answered? (What d they do?) 3. What kind of DATA was or could have been collected? 4. What CONCLUSION(s) can be drawn?

17 Law of C. of Mass: Discussion Strengths of the demonstration? Suggestions for improvement? Sources of possible error? Potential data table?

18 Investigating the Law of C. of Mass Part 1: Pre-Lab Completion Design your own lab using the demo and the guidelines on the handout Groups of 2 or 3 Grading: 1. Pre-Lab (today) 30 pts 20 for completion, 10 for approval 2. Lab Participation (tomorrow) 30 pts Safety, Data, Clean Up 3. Analysis + Conclusions (due Thursday) 40 pts

19 Pre-Lab: Investigation 1. Choose a variable from the ones provided 2. Write your question: How will changing (your variable) affect the difference in mass after a chemical reaction? 3. Hypothesis: If the is changed, then the difference in mass will because. 4. Have your work so far checked by the teacher 5. Materials: Determine what mode of measurement to use 6. Procedure: Write a DETAILED step-by-step process for completing this lab activity 7. Data table: Create YOUR data table to be used in the lab 8. Submit to the teacher for approval

20 Do Now Tuesday Write the formula of the following compounds: 1. Acetic acid 2. Sodium Hydrogen Carbonate 3. Dihydrogen monoxide 4. Calcium carbonate 5. Iron (II) Chloride 6. Potassium Thiocyanate (SCN -1 )

21 Announcements / Reminders Today Lab Activity Friday Notebook Quiz Next week: Monday Homework #10 due Tuesday Unit 5 Quiz 1 Friday Unit 5 Exam

22 Law of C. of Mass: Investigation 1. Use the procedure and data table provided to complete the lab. 2. Gather materials and begin your lab. Be sure to ASK QUESTIONS if needed. 3. When finished, CLEAN UP YOUR STATION, return all lab equipment, and dispose of any trash 4. Pick up the CONCLUSIONS hand out and begin completing it. (Due THURSDAY)

23 Do Now Wednesday 15 grams of vinegar is added to 100 grams of milk and the solution thickens slightly. 1. What does the new solution weigh? 2. Explain how you know. 3. What piece(s) of lab equipment would be used to prove your answer correct?

24 Announcements / Reminders Tomorrow Lab Activity due Friday Notebook Quiz Next week: Monday Homework #10 due Tuesday Unit 5 Quiz 1 Friday Unit 5 Exam

25 Learning Target Summarize characteristics of a balanced chemical equation SWBAT determine the number of atoms present in a chemical formula using coefficients and subscripts Importance?

26 Chemical Equations MUST BE BALANCED In a chemical reaction, atoms are rearranged Atoms are never created or destroyed

27 Chemical Equations Subscript small number written behind an atom Represents the number of only THAT element in the compound Note: NEVER write a 1 Example: CO 2 has 1 C and 2 O

28 Practice Determine the number of each atom in the following: NH 3 MgCl 2 H 2 O Al 2 S 3

29 Chemical Equations Coefficient number IN FRONT OF a molecule Indicates how many of that molecule are present Example: 2 CO 2 indicates 2 molecules of CO 2

30 Chemical Equations To determine how many atoms are present, multiply the coefficient by the subscripts Example: 2 CO 2 # C atoms: 2 x 1 = 2 atoms of C # O atoms: 2 x 2 = 4 atoms of O

31 Practice 2 HCl # H? # Cl? 2, 2 3 HNO 3 # H? # N? # O? 3, 3, 9 5 C 6 H 12 O 6 # C? # H? # O? 30, 60, 30

32 Multiple Subscripts If you have 2 subscripts, multiply the subscripts of the atoms in the parentheses to determine the number of atoms of that element. In general: Coefficient x Subscript x Subscript outside of parenthesis Example: Ca(NO 3 ) 2 # Ca atoms = 1 x 1 = 1 atom of Ca # N atoms = 1 x 1 x 2 = 2 atoms of N # O atoms = 1 x 3 x 2 = 6 atoms of O

33 Practice Mg(OH) 2 #Mg? #O? #H? 1, 2, 2 Cu 3 (PO 4 ) 2 #Cu? #P? #O? 3, 2, 12 Challenge: 2 Fe 2 (CrO 4 ) 3 #Fe? #Cr? #O? 4, 6, 24

34 You try! Determine the number of each type of atom in the following chemical formulas. Raise your hand when finished.

35 Practice 1.2 H 2 O 2.2 Al 2 (SO 4 ) 3 3.Ca 3 (PO 4 ) 2 4.H 2 PO 4 5.H 2 C 6 H 6 O Pb(NO 3 ) CFCs 8. (NH 4 ) 2 SO KClO Al 2 (SO 4 ) 3

36 Independent Practice Complete the independent practice problems Be sure to follow the instructions for each section What you do not finish in class today should be completed for homework

37 Thursday - Announcements / Reminders Today Law of Conservation of Mass Lab due Tomorrow Notebook Quiz Next week: Monday Homework #10 due Tuesday Unit 5 Quiz 1 Friday Unit 5 Exam

38 Learning Target SWBAT summarize characteristics of balanced chemical equations & apply a procedure for balancing them. Importance?

39 Chemical Equations Video

40 Chemical Equations Chemical equations must ALWAYS be balanced Remember: Atoms are REARRANGED; they are NEVER created or destroyed When is an equation balanced? For EACH element, the number of atoms on the reactants (left) side must equal the number of atoms on the products (right) side # Atoms in Reactants = # Atoms in Products

41 Parts of a Chemical Equation Reactants What the reaction starts with Found on the left side of the arrow

42 Parts of a Chemical Equation Yield Sign Separates the reactants and the products Represented with an arrow ( )

43 Parts of a Chemical Equation Products What the reaction produces / ends with Found on the right side of the arrow

44 Is it balanced? Make a list of your elements under the arrow (yield sign) Check to see if you have the same number of each element on BOTH sides of the equation Yes = BALANCED No = UNBALANCED

45 Balanced or Nah? Determine if each of the following reactions are BALANCED or UNBALANCED 1. Zn + 2 HCl ZnCl 2 + H 2 2. FeS + HCl H 2 S + FeCl 2 3. Fe + Cl 2 FeCl H 2 + O 2 2 H 2 O

46 More Practice: B or U? 1. NaI + CaCl 2 2 NaCl + CaI 2 2. LiNO 3 + Ag AgNO 3 + Li 3. AlCl Cs CsCl + Al 4. H 2 O + AgBr HBr + AgOH 5. H 2 + Cl 2 HCl

47 CFU 1 Why must an equation be balanced? For the equation: 4 Al + 3 O 2 2 Al 2 O 3 What are the coefficients? What are the subscripts? Reactants: #Al? #O? Products: #Al? #O? Balanced or unbalanced?

48 Steps to Balancing Equations When copying equations, double check that you wrote down every atom and every number in the correct place 1. Count the number of each type of atom on the left side of the equation 2. Count the number of each type of atom on the right side of the equation 3. Add coefficients to make the number of atoms on the left balance the right

49 Note You can ONLY change coefficients NEVER ADD OR CHANGE SUBSCRIPTS NEVER ADD OR CHANGE SUBSCRIPTS NEVER ADD OR CHANGE SUBSCRIPTS You can ONLY change COEFFICIENTS

50 Then start balancing: [1] Just count up the atoms on each side Mg + O 2 MgO 1 2 Mg [2] The numbers aren t balanced so then add BIG numbers to make up for any shortages And adjust totals O Mg + O Mg O MgO 2 2

51 But the numbers still aren t equal, so add another BIG number 2 Mg + O Mg 2 O MgO 2 2 And adjust totals again NOW BOTH SIDES HAVE EQUAL NUMBERS OF ATOMS WE SAY THAT THE EQUATION IS BALANCED!!

52 More Practice NaI + CaCl 2 NaCl + CaI 2 AlCl 3 + Cs CsCl + Al H 2 + Cl 2 HCl

53 Even More Practice H 2 + N 2 NH 3 Al + O 2 Al 2 O 3 CH 4 + O 2 CO 2 + H 2 O C 2 H 6 + O 2 CO 2 + H 2 O

54 Tips Tip 1: If you cannot easily multiply one side to get the other, multiply the totals by each other Tip 2: If you have C, H, and O in your list, balance H first, then C. ALWAYS save O for last!

55 Balancing Equations: Practice Complete the worksheet for more practice balancing equations You may check your answers with a partner, but you must show your work for each problem and all questions must be answered Checked for completion AND accuracy

56 Friday - Announcements / Reminders Today Notebook Quiz Next week: Monday Homework #10 due Tuesday Unit 5 Quiz 1 Friday Unit 5 Exam

57 Mad Scientist Challenge Partner OR Individual Activity Work with your partner to answer the Mad Scientist s problems You MUST answer the problem that you choose you cannot trade your card for another one You cannot choose a new problem until the one you have is 100% correct First team to complete the mad scientist s challenge will win a prize! (All teams must still complete it)

58 Mad Scientist Challenge For each problem you solve: Write the problem number from the card Write the equation as it is written on the card (with lines for coefficients) Balance your equation Draw a line or box to separate each problem #

59 Balancing Equations: Challenge 25 minutes Complete parts A, B, and ANY 5 equations from part C When finished, raise your hand to be checked for today s participation Once checked, begin working on the independent practice

60 Monday Today Homework #10 due Tomorrow Unit 5 Quiz 1 Friday Unit 5 Exam Next week SPRING BREAK!! Monday, Apr 11 Homework #11 due

61 Homework #11 Due Monday, 4/11 Use your World of Chemistry textbook to complete the following: pg #1 4 pg #9 14 pg #47 49 pg #7, 8, problems

62 Learning Target SWBAT recognize types of chemical reactions. Importance?

63 Draw & Complete this Chart Type of Reaction What Happens General Formula Example

64 Gallery Walk 2 minutes at each station Complete the chart for the reaction type DO NOT ROTATE UNTIL TOLD TO DO SO

65 Synthesis Reaction What happens: 2 or more substances combine to form a new substance General Equation:A + B AB Example: 2 H 2 + O 2 2 H 2 O

66 Decomposition Reaction What happens: 1 substance breaks down, or decomposes, into 2 or more substances General equation: AB A + B Example: 2 NaCl 2 Na + Cl 2

67 Single Replacement Reaction What happens: 1 element replaces another element in a compound General equation: A + BX AX + B Example: 2 KI + Cl 2 2 KCl + I 2

68 Double Replacement Reaction What happens: Positive ion of one compound replaces the positive ion of another compound General equation: AX + BY AY + BX Example: MgCO HCl MgCl 2 + H 2 CO 3

69 Combustion Reaction What happens: Oxygen combines with an organic compound to produce water and carbon dioxide General equation: Carbon compound + oxygen carbon dioxide + water Example: C 10 H O 2 10 CO H 2 O

70 Types of Reactions Single replacement one element takes the place of another element in a compound Example: Zn + 2 HCl ZnCl 2 + H 2

71 Types of Reactions Double replacement exchange of atoms or ions between two compounds Example: FeS + 2 HCl H 2 S + FeCl 2

72 CFU Determine if the following reactions are single or double replacement reactions 1. NaI + CaCl 2 2 NaCl + CaI 2 2. LiNO 3 + Ag AgNO 3 + Li 3. AlCl Cs 3 CsCl + Ag 4. H 2 O + AgBr HBr + AgOH

73 Whiteboard Challenge Purpose: Determine the type of chemical reaction represented by the equation Instructions: Board face down with your answer Marker cap-up in the air CHIN IT! Listen for the explanation, erase, and wait for the next question

74 What type of rxn? (S, D, SR, DR, C) 2 NaBr + Ca(OH) 2 CaBr NaOH 2 NH 3 + H 2 SO 4 (NH 4 ) 2 SO 4 4 C 5 H 9 O + 27 O 2 20 CO H 2 O 3 Pb + 2 H 3 PO 4 3 H 2 + Pb 3 (PO 4 ) 2 Li 3 N + 3 NH 4 NO 3 LiNO 3 + (NH 4 ) 3 N Na 3 PO KOH 3 NaOH + K 3 PO 4 Pb + FeSO 4 PbSO 4 + Fe CaCO 3 CaO + CO 2 P O 2 2 P 2 O 3 C 6 H O 2 6 CO H 2 O

75 The Story Listen to the story as the teacher reads it Answer the following questions: What did the story have to do with chemistry? How did the analogy work? Where was the analogy weak?

76 Types of Rxns Mini Project Create your own analogy Individual Activity Write YOUR OWN ORIGINAL story that contains analogies for all 5 types of fundamental chemical reactions You CANNOT copy the teacher s analogy! It must be long enough to include cohesive comparisons to all 5 reaction types Extra Credit Include illustrations / visuals of parts of your story!

77 Story Rubric All reactions accurately represented Uses complete sentences Uses proper grammar / spelling Story is CREATIVE Story flows well 50 pts 10 pts 20 pts 10 pts 10 pts Total 100 pts Bonus Illustrations 10 pts

78 Independent Practice Use your notes as necessary to complete the worksheet You will practice determining the type of reaction represented each equation If you finish early, check over your work When told, clear your desk for the exit ticket What you do not finish in class will be homework

79 Tuesday - Announcements / Reminders Today Unit 5 Quiz 1 Friday Unit 5 Exam Next week SPRING BREAK!! Monday, Apr 11 Homework #11 Due

80 Learning Target SWBAT write skeleton and balanced equations using the names of compounds in a chemical reaction

81 What is a skeleton equation? An unbalanced equation that does not indicate relative amounts of reactants and products

82 Steps to writing a skeleton equation 1. Identify the reactants (starts with) 2. Identify the products (ends with) 3. Use naming rules to correctly write the chemical formulas of each compound

83 Naming Note Diatomic Molecules always two if element is by itself H, Br, O, N, Cl, I, F Harry BrONClIF Examples: Hydrogen gas H 2 Oxygen gas O 2 You try: What is the formula for chlorine gas?

84 Example #1 Iron (III) Chloride reacts with sodium hydroxide to produce iron (III) hydroxide and sodium chloride

85 Balanced Equation After writing the skeleton equation, balance the equation to finish the chemical equation

86 Balanced Chemical Equation FeCl 3 + NaOH Fe(OH) 3 + NaCl

87 Example #2 Copper (II) sulfide reacts with oxygen gas to produce copper and sulfur dioxide.

88 Example #3 When dissolved beryllium chloride reacts with dissolved silver nitrate in water, aqueous beryllium nitrate and silver chloride powder are made.

89 You try! When fluorine gas is put into contact with calcium metal at high temperatures, calcium fluoride powder is created in an exothermic reaction.

90 Independent Practice Complete the worksheet Write the balanced chemical equation for each problem and determine what type of reaction took place What you do not finish in class will be homework

91 Wednesday - Announcements / Reminders Thursday Review Friday Unit 5 Exam Next week SPRING BREAK!!

92 Skeleton Equations Gallery Walk 5 minutes per station Write the skeleton equation for the reaction and balance it Then, state the type of reaction DO NOT ROTATE UNTIL TOLD TO DO SO

93 Your Paper Equation #: Word equation: Balanced equation:

94 Equation 1 Sodium Iodide reacts with Calcium chloride to yield sodium chloride and calcium iodide

95 Equation 2 Lithium nitrate reacts with silver to produce silver nitrate and lithium

96 Equation 3 Aluminum chloride reacts with cesium metal to produce cesium chloride and aluminum

97 Equation 4 Dihydrogen monoxide (water) reacts with silver (I) bromide to yield hydrogen monobromide and silver (I) hydroxide

98 Equation 5 Hydrogen and chlorine react to yield hydrogen monochloride

99 Equation 6 Magnesium fluoride reacts with lithium carbonate to yield magnesium carbonate and lithium fluoride

100 Equation 7 Hydrogen monochloride reacts with sodium hydroxide to yield sodium chloride and water (dihydrogen oxide)

101 Equation 8 Hydrogen and nitrogen react to form nitrogen trihydride

102 Equation 9 Aluminum oxide decomposes to aluminum metal and oxygen gas.

103 Equation 10 When exposed to hydrogen gas, tin (II) oxide reacts to produce tin and water (dihydrogen monoxide)

104 Independent Practice Complete the worksheet Write the balanced chemical equation for each problem and determine what type of reaction took place

105 Thursday - Announcements / Reminders Today Exam Review Friday Unit 5 Exam Next week SPRING BREAK!! Monday, Apr 11 Homework #11 due

106 Unit 5 Exam Topics Law of Conservation of Mass Types of Reactions Evidence of Chemical Reactions Balancing Chemical Equations Writing skeleton equations

107 Levels Review 12 minutes per station Work with your group to answer the questions You may ONLY use your periodic table & polyatomic ions chart Check your answers when finished Stations: Part 1: Naming Part 2: Counting Part 3: Types of Reactions Part 4: Balancing Part 5: Skeleton Work ethic is part of your qualifiers for tomorrow s exam You WILL turn in your work from today

108 Study Guide Independent Practice Attempt to complete the problems using ONLY your periodic table & polyatomic ions chart May use your notes as necessary Due tomorrow (4/1/16)

109 Friday - Announcements / Reminders Today Unit 5 Exam Next week SPRING BREAK!! Monday, Apr 11 Homework #11 due

110 Unit 5 Exam Independent and SILENT work You may use your periodic table & polyatomic ions chart Be sure to read the directions for each section of the test. All short answer questions should be answered in the space on the BACK of your Scantron When finished, check over your answers. Then, raise your hand so your test can be collected If you finish early, work on this week s homework SILENTLY.