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Chapter 7 and 8

Chemical Reactions

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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

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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

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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.

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http://www.learn360.com/ShowVideo.aspx?lid=26813385&SearchText=chemical+formulas&ID=131918

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1. Calcium oxide 2. Magnesium fluoride

3. Potassium fluoride4. Beryllium oxide

5. Beryllium sulfide 6. Lithium chloride

7. Magnesium sulfide

13. sodium iodide

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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

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12. Barium sulfate

14. Sodium hydroxide

15. Magnesium carbonate

16. Magnesium sulfate17. Ammonium phosphate

18. Calcium carbonate

19. Potassium nitrate

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8. Silver (I) fluoride9. Cobalt (II) chloride10. Nickel (II) chloride11. Cobalt (II) sulfide

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What is a Chemical Reaction?

• When 2 or more pure substances chemically combine to form a “new” substance.

• Chemical change

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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

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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).

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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

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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.

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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

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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.

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Practice

_N2H4 +_O2 __N2 + _H2O

• N: ___ ___

• H: ___ ___

• O: ___ ___

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Practice

___CH4 + ___O2 ___CO2 + ___H2O

C: ________ _________

H: ________ _________

O: ________ _________

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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

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Balanced or unbalanced?

1. KClO2 KCl + 2O2

2. 4Al + 3O2 2Al2O3

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3. N2 + 3H2 2NH3

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4. H2 + O2 H2O

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5. 2NaCl 2Na + Cl2

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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

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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.

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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

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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

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Symbols In an Equation:

What do they mean?

• (s) – solid

• (g) – gas

• (aq) – liquid/aqueous

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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

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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

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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

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Factors affecting solubility – polarity,

temperature, pressureRates of Solutions

(how to speed up a solution)• Stirring• Heating• Powdering-

increasing the surface area

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Electrolytes vs. Nonelectrolytes

• Electrolyte: solution that conducts electricityExample: salt and water or

gatorade

• Non-electrolyte: solution that doesn’t conduct electricityExample: sugar and water

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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.

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What is an Acid

• Definition: A solution in which hydronium ions are present when mixed with water. (H+)

• Example: HCl

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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

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Common Acids

StrongHCl hydrochloric acid

H2SO4 sulfuric acid

HNO3 nitric acid

WeakAcetic acid (vinegar)

Boric acid (eye washes)

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What is a BASE

• Definition: A solution in which hydroxide ions are present. (OH)

• Sodium hydroxide: NaOH

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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

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Common Bases

StrongNaOH - sodium hydroxide

(lye soap)

KOH – potassium hydroxide

Mg(OH)2 laxatives

Weakdeodorants

ammonia

soaps and detergents

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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

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Neutralization

• Definition: A process where an acid and base are chemically combined to form a salt and water.

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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

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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.

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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

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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

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1. U 2. U 3. B

4. U 5. B

Part V1.H2S2.Mg(OH)2

3.NH4Cl4.CaCO3

5.Ba3N2

6.K3PO4

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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