Upload
geoffrey-stephens
View
221
Download
0
Embed Size (px)
Citation preview
1
Chapter 7 and 8
Chemical Reactions
&
Acids and Bases
VALENCE REVIEW• Valence electrons-
number of electrons in outer energy level
• Valence number or oxidation number or valence – number of electrons gained or lost – charge on an ion – positive or negative number
• B groups – Use Roman Numerals
A Groups
2
1A or 1 + or +1 or 1+2A or 2 +2 or 2+3A or 13 +3 or 3+4A or 14 +4 or -45A or 15 -3 or 3-6A or 16 -2 or 2-7A or 17 - or -1 or 1-8A or 18 0
3
Element Valence Electrons Oxidation Number
Sodium
Aluminum
helium
Potassium
Phosphorus
Oxygen
Magnesium
Carbon
Krypton
Nitrogen
Sulfur
chlorine
Iron
1 + or +1 or 1+
3 +3 or 3+
2 0
+ or +1 or 1+
5 -3 or 3-
6 -2 or 2-
2 +2 or 2+
4 + or -4 8 0
1
5 -3 or 3-
6 -2 or 2-
7 - OR -1 or 1-Can’t tell directly Will be given as Roman numeral
Formulas ReviewNaming Compounds (Binary)
Binary- 2 elements1.First element is its name
2.Second element ends in –ide
3.Combine them together
Al2S3
Aluminum sulfide
Answer numbers 1-7, 13 on the Naming Compounds worksheet.
4
http://www.learn360.com/ShowVideo.aspx?lid=26813385&SearchText=chemical+formulas&ID=131918
5
1. Calcium oxide 2. Magnesium fluoride
3. Potassium fluoride4. Beryllium oxide
5. Beryllium sulfide 6. Lithium chloride
7. Magnesium sulfide
13. sodium iodide
6
Naming Compounds (Polyatomic)Polyatomic- more than two
elements. Use the list of ions.1. First element is its name; Last element change to -ide2. Name the polyatomic ion3. Combine together
KNO3 Potassium Nitrate
Answer numbers 12, 14-19
7
12. Barium sulfate
14. Sodium hydroxide
15. Magnesium carbonate
16. Magnesium sulfate17. Ammonium phosphate
18. Calcium carbonate
19. Potassium nitrate
8
8. Silver (I) fluoride9. Cobalt (II) chloride10. Nickel (II) chloride11. Cobalt (II) sulfide
9
What is a Chemical Reaction?
• When 2 or more pure substances chemically combine to form a “new” substance.
• Chemical change
10
VIDEO with notes – Chemical Reactions
Submit 25 video facts for credit.
http://app.discoveryeducation.com/mycontent#mode=MyContent&view=Favorites&guid=81e46573-8ebd-401f-a437-6a78207eec9d
11
Parts of Reactions X + Y XY
• Reactants—the substances that undergo change
• X + Y
• On the left hand side
• Products—the new substances that form as a result of that change
• XY
• On the right hand side
The arrow is read yield(s).
12
Exothermic vs. Endothermic Reaction
Exothermic
Reactions• A chemical reaction
that releases energy to its surrounding
• Surrounding becomes warmer
Endothermic Reactions
• A chemical reaction that absorbs energy from its surrounding
• Surrounding becomes cooler
13
Law of Conservation of
Mass• Matter is neither
created nor destroyed in a chemical reaction
Counting Atoms Practice
1. 2CO2
2. 4H2O
3. 3Ca(NO3)2
4. Mg(OH)2
1. 6
2. 12
3. 27
4. 5Complete worksheet section.
15
Signs of a Reactions
• Production of a gas– Fizzing, bubbling, etc
• Precipitate formation– Insoluble solid forms
• Energy is released– Heat, light, etc
• Color Changes
http://www.learn360.com/ShowVideo.aspx?GradeLevel=3360056&lid=26813385&MediaFormat=3360062&pageAll=2&SearchText=science&Subject=9331501&ID=754741
16
How do I balance an Equation?
• Count the amount of atoms on both sides.
• Place the coefficients in front of compounds and MULTIPLY by any subscript.
• Recount the atoms to see if they balance.
17
Practice
_N2H4 +_O2 __N2 + _H2O
• N: ___ ___
• H: ___ ___
• O: ___ ___
18
Practice
___CH4 + ___O2 ___CO2 + ___H2O
C: ________ _________
H: ________ _________
O: ________ _________
19
Balanced or unbalanced?
1. KClO2 KCl + 2O2
2. 4Al + 3O2 2Al2O3
3. N2 + 3H2 2NH3
4. H2 + O2 H2O
5. 2NaCl 2Na + Cl2
1.Unbalanced2.Balanced3.Balanced4.Unbalanced5.balanced
20
Balanced or unbalanced?
1. KClO2 KCl + 2O2
2. 4Al + 3O2 2Al2O3
21
3. N2 + 3H2 2NH3
22
4. H2 + O2 H2O
23
5. 2NaCl 2Na + Cl2
24
25
Types of Reactions
1. Synthesis A + B ABWhen two or more substances
react to form a single substance
2. Decomposition AB A + BWhen a compound breaks down
into two or more substances
Types of Reactions3. Single replacement (displacement)
BC + A AC + B element and compounds – one element replaces another
4. Double replacement (displacement) AB + CD CB + AD all compounds – exchange
positive ions to form new compounds
27
Special Reactions• Combustion of a hydrocarbon – A combustion reaction takes the following form:
•Hydrocarbon + Oxygen carbon dioxide + water
CH4 + 2O2 CO2 + 2H2O• Products are always carbon dioxide and water!!!
Cellular respiration is a combustion reaction.
28
Products of Reactions
Precipitate• insoluble compound
formed during a double replacement reaction.
Hydrate• chemical compound
that has water molecules attached to it.
Chemical Reactions Activity
• http://www.bing.com/videos/search?q=types+of+chemical+reactions+video&qpvt=types+of+chemical+reactions+video&FORM=VQFRML#view=detail&mid=12EA038451F2B3826AF112EA038451F2B3826AF1
29
http://www.bing.com/videos/search?q=types+of+chemical+reactions+video&qpvt=types+of+chemical+reactions+video&FORM=VQFRML#view=detail&mid=332009DCF5B5F68C7770332009DCF5B5F68C7770
Type of Reaction
Definition Equation
Synthesis
Decomposition
Single Replacement
Double Replacement
Watch the movie and then complete the chart.
A = Red B = Blue C = Green D = Yellow
A + B → AB
AB → A + B
BC + A → AC + B
AB + CD → CB + AD
Two or more elements or compounds combine to make a more complex
substance
Compounds break down into simpler substances
Occurs when one element replaces another one in a
compound
Occurs when different atoms in two different
compounds trade places
Identifying Chemical Reactions
____ P + O2 → P4O10 ____ Mg + O2 → MgO
____ HgO → Hg + O2 ____ Al2O3 → Al + O2
____ Cl2 + NaBr → NaCl + Br2 ____ H2 + N2 → NH3
2. Use colored pencils to circle the common atoms or compounds in each equation to help you determine the type of reaction it illustrates. Use the code below to classify each reaction.
S = Synthesis D = Decomposition SR = Single Replacement DR = Double Replacement
____ Na + Br2 → NaBr ____ CuCl2 + H2S → CuS + HCl
____ HgO + Cl2 → HgCl + O2 ____ C + H2 → CH4
____ KClO3 → KCl + O2 ____ S8 + F2 → SF6
____ BaCl2 + Na2 SO4 → NaCl + BaSO4
33
Symbols In an Equation:
What do they mean?
• (s) – solid
• (g) – gas
• (aq) – liquid/aqueous
34
Reaction Rates(SPEED UP REACTIONS)
1. Collision: molecules hit one another creating friction
2. Concentration: more solute the faster the reaction will go
3. Surface area: more area exposed will cause a faster reaction
4. Heat: the more heat is added, the faster the reaction
5. Catalyst: something added to speed up a reaction without it changing
35
Solutions• Make a list – goal 100
• What is a Solution? – Where one substance must
dissolve in another
• Solubility: ability of a solute to dissolve in a solvent
http://www.learn360.com/ShowVideo.aspx?GradeLevel=3360056&lid=26813385&MediaFormat=3360062&SearchText=pH&Subject=9331464&ID=132037
36
Parts of a Solution
• Solute – Part being dissolved in the solvent.
ex: Sugar, hot chocolate
• Solvent – Part that does the dissolving.
ex: Water – universal solvent
37
Factors affecting solubility – polarity,
temperature, pressureRates of Solutions
(how to speed up a solution)• Stirring• Heating• Powdering-
increasing the surface area
38
Electrolytes vs. Nonelectrolytes
• Electrolyte: solution that conducts electricityExample: salt and water or
gatorade
• Non-electrolyte: solution that doesn’t conduct electricityExample: sugar and water
39
Levels of Solutions
• Unsaturated – Holding little solute in much solvent
• Saturated – Holding as much solute at a given temperature
• Supersaturated – UNSTABLE – more solute in the solvent at a high temp.
40
What is an Acid
• Definition: A solution in which hydronium ions are present when mixed with water. (H+)
• Example: HCl
41
Characteristics of Acids
• Sour• React violently with
metals (corrosion)• pH levels of 0-6 • Electrolyte- conducts
electricity• Burn the skin• Formulas start with H
due to the hydronium ions present
42
Common Acids
StrongHCl hydrochloric acid
H2SO4 sulfuric acid
HNO3 nitric acid
WeakAcetic acid (vinegar)
Boric acid (eye washes)
43
What is a BASE
• Definition: A solution in which hydroxide ions are present. (OH)
• Sodium hydroxide: NaOH
44
Characteristics of Bases
• Taste bitter• Slippery/Soaps• Formula ends in OH• Proton acceptor –
looking for H+• pH scale of 8-14• Will burn the skin
45
Common Bases
StrongNaOH - sodium hydroxide
(lye soap)
KOH – potassium hydroxide
Mg(OH)2 laxatives
Weakdeodorants
ammonia
soaps and detergents
46
pH Scale• pH scale is from 0 to 14• Acids range from 0 to 6• A strong acid has a pH of 0-2• Bases range from 8 to 14• A strong base has a pH of 10-14• Distilled pure water has a pH of 7
47
Neutralization
• Definition: A process where an acid and base are chemically combined to form a salt and water.
48
Neutralization is what type of reaction?
• The type of reaction that occurs during a neutralization process is
DOUBLE REPLACEMENT
HCl + NaOH NaCl + H2O
Acid Base Salt Water
REACTANTS PRODUCTS
49
IndicatorsTypes of
IndicatorsAcid Base
Blue Litmus Paper
Turns red in acid
No change
Red Litmus Paper
No change Turns blue in base
pH Paper Red, orange and yellow
tints
Blue-green to dark blue tints
Phenolphthalein Clear Hot pink
Chapter 7 and 8 Study Guide
1. Reactants are the beginning substances that undergo chemical change in a reaction. They are on the left side – before the arrow.
2. Products are the ending substances that are produced in a chemical reaction They are on the right side – after the arrow.
50
3. Endothermic reactions absorb energy and exothermic release energy.4. Matter or mass cannot be created nor destroyed during a chemical reaction.5. Aq – aqueous; s – solid or precipitate ; g – gas or gaseous
6. Coefficients
7. Change in temperature; production of a gas (fizzing, bubbling, smoke; change in properties such as color or odor; release of energy – heat, light, sound; production of a precipitate 51
8. collision; concentration; surface area; catalyst; heat9. a. decompostion;
b. Single replacement
c. Double replacement
d. Synthesis
e. combustion 52
10. Carbon dioxide and water
53
13. a compound that produces hydroxide ions when dissolved in water;strong – sodium hydroxide and potassium hydroxide; weak - aluminum hydroxide used in deodorant; soaps
12. a compound that produces hydronium ions when dissolved in water; strong – hydrochloric or sulfuric; weak – acetic or citric
11. A solid formed as a product of a chemical reaction; solid at bottom of container
14. Reactants – acid and base
products – salt and water
15. 0 -2; 0-6 16. 12-14 ; 8 -14
17. 7 ; pure water
18. Compounds which conduct electricity when in solution; acids, bases, and salts
Part 11 1. Be – 1; O – 1 2
2. N – 1; H – 5; O – 1 7
3. Al – 9; O – 6 15 54
6. calcium chloride55
4. O – 6 6
5. N – 3; H – 12; P – 1; O – 4 20 6. Ca – 3; Cl – 6 9Part III 1. beryllium oxide2. ammonium hydroxide
3. aluminum oxide4. oxygen 5. ammonium phosphate
Part IV
56
1. U 2. U 3. B
4. U 5. B
Part V1.H2S2.Mg(OH)2
3.NH4Cl4.CaCO3
5.Ba3N2
6.K3PO4
57
Balancing Equations Worksheet3. SR 4. SR 5. D 6. S
7. D 8. S 9. S 10. SR
11. S
12. S 13. Combustion or D
14. S 15. SR 16. Combustion or D
17. SR 18. S 19. SR 20. DR
21. Combustion or D 22. D 23. D
24. D 25. D 26. D 27. DR
28. SR 29. D 30. SR