1. Ch 7: Chemical Reactions

2. Title and Highlight Right Side – NOTES ONLY TN Ch 7.1 Date Topic: EQ:
Book Questions:
Write Question out (left side of red line) and answer it (Highlight answer) based on from what you read.
Notes:
Write out the notes from my website.
You may use different color pens.
Use Bullets or Number notes.
Space out your notes so you can add any additional into during lecture.
NO HIGHLIGTING, UNDERLINING, etc
WE WILL DO OUR FOCUS NOTES TOGETHER
Summary:
Write 2-3 sentences (end of notes) from what you learned from reading, notes, and/or lecture.

3. Title and Highlight
LEFT Side – PICTURES, PRACTICE PROBLEMS, ETC
TN Ch 5.11
DRAW ANY PICTURES, FIGURES, AND WRITE OUT ANY PRACTICE PROBLEMS/QUESTIONS.
WE WILL ANSWER THEM TOGETHER. LEAVE SPACES SO WE CAN ANSWER QUES.

4. Ch 7.1-7.2: Chemical Reactions
Topic: Evidence of Chem Reaction
EQ: What evidence can you see that a chem reaction has occurred?
READ Ch (pg )
Write Questions & Answer Questions #1-3 (notes side) Highlight answer

5. Chemical reactions take place all around us and even inside us.
They are involved in many of the products we use daily.

6. If we could see the atoms and molecules that compose matter, we could easily identify a chemical reaction:
Atoms combine with other atoms to form compounds.
Original molecules decompose.
Atoms in one molecule change places with atoms in another.

7. We could know a chemical reaction has occurred by observing these changes.
Just remember Ch 3… a chemical change (reaction) produced something new!!

8. Evidence of a Chemical Reaction (VERY IMPORTANT!!!)
The following 5 provides evidence (can see with our eyes) of a chemical reaction: • A color change • The formation of a solid (precipitate) • The formation of a gas, smoke, odor, bubbles • The emission of light • The emission or absorption of heat

9. Evidence of a Chemical Reaction

10. Evidence of a Chemical Reaction

11. NOT Evidence of a Chemical Reaction
We can be fooled.
When water boils, bubbles form and a gas is evolved, but no chemical reaction has occurred.
Boiling water forms gaseous steam (still water) - no chemical change has occurred.

12. Practice Problems #1:
Left side
Which changes involve a chemical reaction? EXPLAIN!!
A. ice melting
B. An electric current passing through water, resulting in formation of H and O gases.
C. Iron rusting
D. Bubbles forming when a soda can is opened.
B and C

13. Left side
Practice Problems #2:
Which changes involve a chemical reaction? EXPLAIN!!
A. Butane burning in a lighter
B. Butane evaporating out of a lighter
C. Wood burning
D. Dry ice subliming (turns from solid to gas)

14. Ch 7.3: Chemical Equations
Topic: Chem Equation
EQ: What are the rules for writing a balanced chem equation?
READ Ch 7.3 (pg )
Write Questions & Answer Questions #4-6 (notes side) Highlight answer

15. Ch. 7.3 Notes -- Chemical Reactions
We represent chemical reactions with chemical equations.
Chemical equations give information about the REACTANTS & PRODUCTS
Review: Reactants: ______ side of the arrow Products: __________ side.
Example of a Balanced Chemical Equation:
2H2 (g) + O2 (g)  2H2O (g)
States of Matter (S.O.M.) - each chemical has it in parentheses next to the formula.
Ch. 7.3 Notes -- Chemical Reactions
left
right

16. Common Symbols used in Chemical Equations
(See Table 7.1)
+ = used to separate 2 reactants or 2 products from each other
→ = “yields” or “reacts to produce”
= _____________ reaction (like a rechargeable battery)
(s) (l) (g) (aq) = phase of matter: (solid, liquid, gas, or “aqueous”)
= ___________ supplied to the reaction
MnO2 = a catalyst, (in this case, MnO2), is used to ________ ____ the reaction.
reversible
heat
speed up

17. Balancing Chemical Equations
Why do you have to balance a chemical equation?
Law of Conservation of Matter (or Mass): “Matter is neither ____________ nor _______________ in chemical reactions, ITS CONSERVED (REARRANGED)!!!.”
During a chemical reaction, atoms are either _________, ______________, or rearranged. The _____________ and type of each atom stays the same.
How do you balance a chemical equation?
__________________ are placed in front of the substances to get the same number of atoms of each element on both sides of the equation.
created
destroyed
joined
separated
number
Coefficients

18. Do you know how to count? Practice Problem #1
Left side
Practice Problem #1
How many atoms of each element are there in each compound?
Ca(OH)2 ___
C3H8O___
(NH4)2HPO4 ___
HC2H3O2 ___

19. RULES - Balance a chemical equation
Use Atom inventory:
(This is how you show your work)
Split the equation in half (under the arrow) and list the elements.
Count # atoms you see on both the reactant AND product side.
If all atoms on each side are equal, then the equation is called a “balanced chemical equation”
If not (most of the time), then you must balance the equation by adding coefficients (BIG #’s in the front of chemicals.

20. The Chemical Equation: Combustion of Methane
We represent this skeleton (unbalanced – no coefficents) reaction with the following equation:
With states included, the equation becomes

21. Draw Pics also with the notes!!
The left side of the equation has two oxygen atoms and the right side has three.
Atoms cannot simply appear or disappear in chemical equations. We must account for the atoms on both sides of the equation.

22. To correct these problems, we must create a balanced equation.

23. (AKA…Law of Cons. of Matter is valid!!!)
Draw Pics also with the notes!!
The equation is now balanced  because the #’s of each type of atom on both sides of the equation are equal.
(AKA…Law of Cons. of Matter is valid!!!)

24. Checking the Balanced Equation
If there are no coefficients, a 1 is implied (but we never write 1’s).
The balanced equation is as follows:

25. Coefficients can only be placed ___ _________ of a chemical formula.
Practice Problem #2: How many atoms of each type are indicated in
the following compounds?
(a) 2 (NH4)3PO N= ___ H= ___ P= ___ O= ___
(b) 4 KC2H3O K= ___ C= ___ H= ___ O= ___
(c) 3 Ca(NO3) Ca= ___ N= ___ O= ___
Left side
in front

26. Rules for Balancing Chemical Equations
(1) You cannot change a ________________!! Example : H2 + O2  H2O To balance oxygen, you cannot change water’s formula to_________! (2) You cannot place the coefficient in the ______________ of a formula!! Example : Al + N2  AlN To balance nitrogen, you cannot put a 2 in the middle to make _______. (3) Reduce the coefficients to the simplest ____________ ___ ratio. Example: 4H2 + 2O2  4H2O can be reduced to… __H2 + __O2  __H2O
subscript 2 2
H2O2
middle 2 2
Al2N
whole # 2 1 2

27. Practice Problem #3: Balance Equations by adding coefficients
Left side – leave 5 spaces between questions
Practice Problem #3: Balance Equations by adding coefficients
a) ___(NH4)2CO3  ___NH ___CO ___H2O
b) ___Al ___CuSO4  ___Al2(SO4) ___Cu
c) ___Fe(OH)3  ___Fe2O ___H2O
___Li ___H2O  ___LiOH ___H2

28. Ch 7.4: Balancing Equations
Topic: Writing Chem Equations
EQ: How do you write a balanced chem equation with no formulas?
READ Ch 7.4 (pg )
Write Questions & Answer Questions #7 (notes side) Highlight answer

29. How to Write Balanced Chemical Equations
Write a skeleton (unbalanced) equation by writing correct chemical formulas.
DON’T FORGET TO BALANCE THE CHARGES!! (Use Polyatomic card)
2. Once you have written all formulas, write in your S.O.M. (as many as possible).

30. Balance the equation by adding COEFFICIENTS (BIG #’s in the front).
VERY IMPORTANT!!...you can change only the coefficients to balance a chemical equation; never change the subscripts.
Rewrite final balanced equation at the end of problem (and highlight)

31. Left side – leave 5 spaces between questions
Practice Problem #1: Write a skeleton equation from words:
Solid aluminum reacts with aqueous sulfuric acid to form aqueous aluminum sulfate and hydrogen gas

32. Left side – leave 5 spaces between questions
Practice Problem #2: Write a skeleton equation from words:
Sodium reacts bromine, when heated, reacts to produce solid sodium bromide

33. Writing Skeleton Equations
Left side – leave 5 spaces between questions
Practice Problem #3: Write the following equations into words using complete sentences.
a) NaHCO3 (s) + HCl (aq)  NaCl (aq) + H2O (l) + CO2 (g)
b) H2SO4 (aq) + BaCl2 (aq)  HCl (aq) + BaSO4 (s)

34. Ch 7.5: Balancing Equations
Topic: Aqueous Solutions
EQ: How do you determine if a solution is aqueous?
READ Ch 7.5 (pg )
Write Questions & Answer Questions #8-13 (notes side) Highlight answer

35. soluble – a compound that dissolves in that liquid.
insoluble - does not dissolve in the liquid.
An aqueous solution is a homogeneous mixture (solution) of a substance with water.
When ionic compounds dissolve in water, they usually dissociate (break apart) into their component ions.

36. The Light Bulb Demonstration bright glow weak glow no glow
Strong Electrolyte Weak Electrolyte Nonelectrolyte
100% completely dissociate into ions
Types: Ionic Compounds, Strong Acids & Bases
Examples: salt water, HCl, drain cleaner
partially (not 100%) dissociate into ions
Types: Weak Acids & Bases
Examples: tap water, vinegar
no dissociation
Examples: pure (DI) water, sugar in water, oil, alcohol

37. Aqueous Solutions: not all Dissolve in Water
Not all ionic compounds dissolve in water.
AgCl does not dissolve in water.
AgCl remains as a solid, AgCl(s), within the liquid water.
It does not dissolve or dissociate into ions.

38. Solubility Rules: muy importante!!
If not all ionic compounds dissolve, then how do we know without performing experiments?
We use solubility rules.

39. Will be given to you on tests!!
Any compound that contains these ions is always soluble except with the ions listed
Any compound that contains these ions is never soluble except with the ions listed
Solubility Rules Chart Any compound not listed in these general rules is considered insoluble.

40. Solubility: Mostly Insoluble
Note that the solubility rules contain many exceptions.
Let’s practice how to read the chart
Look at carbonate (CO3 -2)

41. Solubility: Mostly Insoluble
Exceptions.
For example:
compounds containing the CO32− ion are insoluble.
CaCO3, FeCO3, SrCO3, and CuCO3 = do not dissolve in water. (SOLIDS)
HOWEVER - compounds containing CO32− are soluble when paired with Li+, Na+, K+, or NH4+.
Li2CO3, Na2CO3, K2CO3, and (NH4)2CO3 are soluble. = a.q.

42. Practice Problems #1 Ca(NO3)2 AgCl Ni(OH)2
Left side
Practice Problems #1
Practice using the solubility rules for the following compounds:
Ca(NO3)2
AgCl
Ni(OH)2

43. Practice Problems #2 Which of the following are soluble in water?
Left side
Practice Problems #2
Which of the following are soluble in water?
SrSO4
NaNO3
PbCl2
AgBr
CaCl2
Pb(NO3)2
PbSO4

44. Topic: Precipitate Rxn
Ch 7.6
Topic: Precipitate Rxn
EQ: How do we determine the products of a precip. rxn?
READ Ch 7.6 (pg )
Write Questions & Answer Questions #14-15 (notes side) Highlight answer

45. Precipitate reactions (rxn), reactions that form a solid (s), called a precipitate, upon mixing two aqueous solutions.
Also called Double Replacement (DR) reactions

46. + + DR/Precipitate Rxns:
A reaction between _____ ________________ that are (aq) that produces _____ ________________ , one of which is _____________(produces s, l, or g)
THINK FOIL!!
General Form: ____ + ____  ____ + ____
A solid produced during a chemical reaction is called a precipitate.
two compounds
two compounds
insoluble
AX(aq)
BY(aq)
AY(aq)
BX(s) + +

47. precipitate because it is insoluble (solid) according to
Predict the products of the following reaction: (Need Solubility Rules!!)
Pb(NO3)2(aq) + KI (aq) 
Pb(NO3)2(aq) + 2KI (aq)  PbI2(s) + 2KNO3 (aq)
We know it is a solid
precipitate because it is
insoluble (solid) according to
the solubility rules.

48. a brilliant yellow precipitate of PbI2(s) forms.
Precipitation
a brilliant yellow precipitate of PbI2(s) forms.

49. No precipitate, liquid, or gas forms, which means no reaction.
What about…..
Na Cl (aq) + KI (aq) 
NaCl (aq) + KI (aq)  NaI(aq) + KCl (aq)
(BORING RXN!)
So, if no reaction occurs…..
NaCl (aq) + KI (aq)  NR
(no reaction)
No precipitate, liquid, or gas forms, which means no reaction.

50. Precipitation reactions do not always occur when mixing two aqueous solutions.
Sometimes…no reaction occurs.

51. Predicting Precipitation Reactions
The key to DR/ Precipitate reactions is only insoluble (solids) compounds form precipitates.
Rules:
Write a skeleton equation
Combine the cation (+) from one reactant with the anion (-) from the other. (THINK FOIL!!!)
Balance charges - formulas for the new products.

52. Writing Equations for Precipitation Reactions
3. Use the solubility rules - determine whether any of new products are insoluble = solid.
4. If all products are (aq) = soluble, there will be no precipitate. Write NO REACTION (NR) next to the arrow. (Still have to write reactants!!)

53. Writing Equations for Precipitation Reactions
Example: Solutions of sodium carbonate Na2CO3(aq) and copper(II) chloride CuCl2(aq) are mixed. (Balance your charges)

54. Na2CO3(aq) + CuCl2(aq) → CuCO3(s) + NaCl(aq) (This is only a skeleton rxn. We still need to……)

55. Writing Equations for Precipitation Reactions
Balance the equation.
Only adjust coefficients, not the subscripts.
Na2CO3(aq) + CuCl2(aq) → CuCO3(s) + 2 NaCl(aq)

56. Topic: Types of Reactions
Ch (part 1)
Topic: Types of Reactions
EQ: What is the difference between the 8 types of Rxns?
READ Ch (pg )
Write Questions & Answer Questions #17-19 (notes side) Highlight answer

57. General Types of Reactions (Continued)
1) _______________ Replacement:
A reaction between _____ ________________ that are dissolved in water that produces _____ ________________ , one of which is ________________ (s, l, or gas) .
General Form: ____ + ____  ____ + ____
2) A solid produced during a chemical reaction is called a precipitate.
Examples: CaCl2 (aq) AgNO3 (aq)  _________ + ________
NaOH (aq) + HCl (aq)  ________ + ________
Double
two compounds
two compounds
insoluble
AX(aq)
BY(aq)
AY(aq)
BX(s) + +

58. Ch 7.8 Acid–Base Reactions
3) Acid–base reactions are reactions that form water and a salt (Ionic Compound).
Also called neutralization reactions.

59. Some Common Acids and Bases

60. Practice ProbLems #1 Write a balance equation for the following:
Left side
Practice ProbLems #1
Write a balance equation for the following:
HNO3 + Ca(OH)2 

61. Gas Evolution Reactions:
4. Gas Evolution Rxns – produce a GAS!!! 1. Write a skeletal equation HNO3(aq) + Na2CO3(aq) → H2CO3(aq) + NaNO3(aq) (If you form this..ding ding!!) 2.You must recognize that H2CO3(aq) decomposes into H2O(l) and CO2(g) and write the corresponding equation. HNO3(aq) + Na2CO3(aq) → H2O(l) + CO2(g) + NaNO3(aq) 3. Finally, balance the equation. 2 HNO3(aq) + Na2CO3(aq) → H2O(l) + CO2(g) + 2NaNO3(aq)

62. Practice Problem #2 Write a balance equation for the following:
Left side
Practice Problem #2
Write a balance equation for the following:
hydrobromic acid + potassium sulfite (aq) 

63. Gas Evolution Reactions

64. Topic: Types of Reactions
Ch (part 2)
Topic: Types of Reactions
EQ: What is the difference between the 8 types of Rxns?
READ Ch (pg )
Write Questions & Answer Questions #21, 23 (notes side) Highlight answer

65. Ch 7.8 Seven Types of Reactions
5)_______________: (sometimes called “Synthesis”)
A reaction of _____ __________________, typically a metal and a nonmetal to form ______ ______________.
It is the opposite of decomposition.
General Form: ___ ___  _____
Examples: Al (s) Cl2 (g) _______
PbO (s) + H2O (l)  ______
Combination
two substances
one compound + A X AX

66. + Types of Reactions 6) ________________________: Decomposition
A reaction that breaks apart ______ ______________ into simpler substances, (usually two elements or an element and a smaller compound.)
General Form: _____  ___ + ___
Examples: H2O  _____ + _____
KCl  ___ _____
Remember that “H,N,O,F,Cl,Br,I” elements are diatomic when alone!!
Decomposition
one compound + AX
A X

67. General Types of Reactions (Continued)
Combustion
7) _________________: Reacts with oxygen gas!!!
Combustion reactions are exothermic (they emit heat).
A reaction between a Carbon/Hydrogen with _____ always produces the same… ________ + ________
This reaction is too easy!! Don’t miss it!
General Form: CxHy + O2  ____ + ____
Examples: C2H O2  _______ + _______
C7H6O O2  _______ + _______ O2
CO2
H2O
CO2
H2O

68. Balancing Equations:Combustion
___Al ___O2 
___ S ___O2 
Left side – Leave space to show work
Practice Problem #1

69. Topic: Types of Reactions
Ch (part 3)
Topic: Types of Reactions
EQ: What is the difference between the 8 types of Rxns?
READ Ch (pg )
Write Questions & Answer Questions #24 (notes side) Highlight answer

70. General Types of Reactions (Continued)
8) _____________ Replacement:
A reaction between ____ ______________ and ___ ____________ that produces a different _____________ and ______________.
General Forms:
____ + __  ____ __
The element that is trying to replace the other must be ________ _______________ than the one it is replacing.
You must use the Activity Series to see if the reaction will happen.
See chart _________ ___ = more reactive
Single
one compound
one element
compound
element + AX Y AY X
more
reactive
Higher up

71. Activity Series

72. Single Replacement Reactions
Practice Problem #1
NaCl F2  _____ + _____
FeCl K  _____ + _____
HCl Zn  _____ + _____
HCl Au  _____ + _____
H2O Na  _____ + _____
H2O Fe  _____ + _____
AgNO3 + Cu  _____ + _____
Left side – Leave space to show work

73. Topic: Types of Reactions EQ: What are all 8 types of Rxns?
Ch 7.10
Topic: Types of Reactions
EQ: What are all 8 types of Rxns?
READ Ch 7.10 (pg )
NO BQ’s

74. 8 Types of reactions: Let’s Review Combination (also called synthesis)
Decomposition
Combustion
Single Replacement
Double Replacement
Acid/Base
Precipitate
Gas Evolution

76. Ch 7.7
SKIP!!

77. Ch 7.7 : Molecular and Complete Ionic Equations
There are rxns that occur where not ALL ions participate.
Some ions do all the work and some ions just watch the show happen.
To show this is an equation, we write a net- ionic equation:
A “net ionic equation” only shows the ions that were used to make the precipitate (solid).
Basically shows only the ions doing all the work to make the precipitate and gets rid of the useless ions.

78. Ch 7.7 : Molecular and Complete Ionic Equations
1st Step: Need a molecular equation (also called BALANCED equation)
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
2nd Step: Write an Ionic equation - shows all (aq) ionic compounds dissociated in solution. (Break them apart)
Separate only (aq) into their ions.
Do NOT separate any solid, liquid, or gas compounds. They DO NOT dissociate!!
Ag+(aq) + NO3−(aq) + Na+(aq) + Cl−(aq) → AgCl(s) + Na+(aq) + NO3–(aq)

79. Specator IOns
In the ionic equation, some of the ions in solution appear unchanged on both sides of the equation.
These ions are called spectator ions because they do not participate in the reaction. (Basically they do nothing in the reaction)

80. Ag+(aq) + Cl− (aq) → AgCl(s)
Writing Chemical Equations for Reactions in Solution: Complete Ionic and Net Ionic Equations
3rd Step: Cross out ALL spectator ions.  
***To cross out, you must have same amount on each side.
Equations such as this one, which show only the ions that actually participate in the reaction, are called net ionic equations.
Ag+(aq) + Cl− (aq) → AgCl(s)

81. Write the ionic and net-ionic equations
Remember this reaction from earlier section:
Pb(NO3)2(aq) + 2KI (aq)  PbI2(s) + 2KNO3 (aq)
Write the ionic and
net-ionic equations

82. A picture of the reaction:
Because K+ and NO3- are spectator ions and are not included in the net ionic equation. Net Ionic Equation Pb2+ (aq) + 2I-(aq)  PbI2(s)
NO3-
NO3-
Pb2+ K+ I- K+
NO3-
PbI2(s)

83. Difference between Molecular, Complete Ionic, and Net Ionic Equations
To summarize: A molecular (Balanced) equation is a chemical equation showing the complete, neutral formulas for every compound in a reaction. An ionic equation is a chemical equation showing all of the species as they are actually present in solution. A net ionic equation is an equation showing only the species that actually participate in the reaction.