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•IDENTIFY AND BALANCE 5 TYPES OF REACTIONS
•EXPERIMENTALLY DETERMINE INDICATORS OF A REACTION
Unit Five: Chemical Reactions
Chemical Reactions
Process by which the atoms of one or more substances are rearranged to form different substances
Law of Conservation of Matter – Matter is not created or destroyed during a chemical reaction.
Evidence of a Chemical Reaction
1. Formation of a gas Bubbles Smell
2. Formation of a solid (precipitate) from two aqueous solutions; often solids are colorful
“Snow globe” effect “Paint” look “Jello” consistency
3. Change in temperature Test tube feels colder to you (endothermic
reaction) Test tube feels warmer to you (exothermic
reaction)
Writing Chemical Equations
Read a description of the reactionNote what is reacted with whatNote what is yielded or producedWrite formulas for each compoundUse + to represent “and”Use to represent “produces” or
“yields”Include states of matter where available
(s) solid (l) liquid (g) gas (aq) dissolved in water
Balancing Chemical Equations
Write the skeleton equation. BE SURE THE FORMULAS ARE WRITTEN
CORRECTLY.Inventory reactantsInventory productsInsert coefficients to make atoms of
each element equal on both sides of the equation
Reduce the coefficients if possible
Writing & Balancing Equations Handout
1. Zn + Pb(NO3)2 --> Zn(NO3)2 + Pb
2. AlBr3 + Cl2 --> AlCl3 + Br2
Writing & Balancing Equations
1. Zn + Pb(NO3)2 --> Zn(NO3)2 + Pb
2. 2 AlBr3 + 3 Cl2 --> 2 AlCl3 + 3 Br2
3. Na3PO4 + CaCl2 --> Ca3(PO4)2 + NaCl
Writing & Balancing Equations
1. Zn + Pb(NO3)2 --> Zn(NO3)2 + Pb
2. 2 AlBr3 + 3 Cl2 --> 2 AlCl3 + 3 Br2
3. 2 Na3PO4 + 3 CaCl2 --> Ca3(PO4)2 + 6 NaCl
Complete 4, 5, 6, and 8 on your own.
Potassium metal and chlorine gas combine to form potassium
chloride.
Select the balanced chemical equation.A.) K+1 + Cl- --> KCl
B.) K + Cl --> KCl
C.) K + Cl2 --> KCl
D.) 2K + Cl2 --> 2KCl
Aluminum and hydrochloric acid react to form aluminum chloride
and hydrogen gas.Select the balanced chemical
equation.A.) Al+3 + HClO3 --> AlCl + H
B.) Al + 2HClO3 --> AlCl3 + H2
C.) Al + HCl --> AlCl3 + H2
D.) 2Al + 2HCl --> 2AlCl3 + 3H2
E.) 2Al + 6HCl --> 2AlCl3 + 3H2
Calcium hydroxide and phosphoric acid react to form calcium phosphate and water.Select the balanced chemical
equation.A.) CaOH2 + H3P --> Ca3(PO4)2 + H2O
B.) 3CaOH2 + 2H3PO4 --> Ca3(PO4)2 + 6H2O
C.) 3Ca(OH)2 + H32PO4 --> Ca3(PO4)2 + 3H2O
D.) 3Ca(OH)2 + 2H3PO4 --> Ca3(PO4)2 + 6H2O
Hydrogen gas and nitrogen monoxide react to form water
and nitrogen gas.Select the balanced chemical
equation.A.) 2H + NO --> H2O + N
B.) 6H + N2O3 --> 3H2O + 2N
C.) 2H2 + 2NO --> 2H2O + N2
D.) H2 + 2NO --> H2O + N2
Copper and sulfuric acid react to form copper (II) sulfate and water and sulfur
dioxide.
Difficult Equations to Balance
Cu + 2 H2SO4 --> CuSO4 + 2 H2O + SO2
Writing & Balancing Equations
1. Zn + Pb(NO3)2 --> Zn(NO3)2 + Pb
2. 2 AlBr3 + 3 Cl2 --> 2 AlCl3 + 3 Br2
3. 2 Na3PO4 + 3 CaCl2 --> Ca3(PO4)2 + 6 NaCl
4. 2 K + Cl2 --> 2 KCl
5. 2 Al + 6 HCl --> 2 AlCl3 + 3 H2
6. 3 Ca(OH)2 + 2 H3PO4 --> Ca3(PO4)2 + 6 H2O
7. Cu + 2 H2SO4 --> CuSO4 + 2 H2O + SO2
8. 2 H2 + 2 NO --> 2 H2O + N2
5 Types of Chemical Reactions
SynthesisCombustionDecompositionDouble-ReplacementSingle-Replacement
Five Types of Reactions Clip
Synthesis Reactions
A + B --> AB2 or more compounds or elements go
together to build a more complex compound
Synthesis Reaction Clip
Write the balanced chemical equation for the reaction shown in the video clip.
2Al + 3Br2 2AlBr3
Combustion Reactions
Oxygen combines with a substance and releases energy in the form of heat and light
DIATOMIC OXYGEN IS ALWAYS A REACTANT!
Combustion Reaction Clip
In the video, the combustion reaction occurring in the flask used up all of the
oxygen gas in flask. A vacuum formed as a result, and the egg was drawn into the
flask.
Decomposition Reactions
A single compound breaks down into 2 or more elements or new compounds
AB --> A + B
Decomposition Reaction Clip
In the video, hydrogen peroxide is decomposed to form hydrogen gas and oxygen gas. Many
bubbles indicated this gas production. A catalyst of KI was used to speed up the decomposition
reaction.
Double Replacement Reactions
Exchange of ions between 2 ionic compounds
AX + BY AY + BXOften produce a precipitate
Solid, liquid, or gas product formed from two “aqueous” solutions
Aqueous means dissolved in water.Example: Cobalt (II) chloride reacts with
sodium phosphate to produce cobalt (II) phosphate and sodium chloride.
Single Replacement Reactions
One element replaces another element in a compound
A + BX --> AX + BA metal will not always replace another metal.
The reactivity of the metal is important to consider. Only a more active metal replaces a less active metal. A less active metal will not replace a more active metal.
The reaction will simply not occur.Use the metal activity series to determine if
single replacement reactions occur.
Colored Pencil Corrections9-2 Practice Problems (odd)
1. NH3 + HCl NH4Cl
3. BaO + H2O Ba(OH)2
5. Zn + Cu(NO3)2 Zn(NO3)2 + Cu
7. Fe + H2SO4 FeSO4 + H2
9. Co + Cl2 CoCl2
11. N2O5 + H2O 2HNO3
13. C + 2ZnO 2Zn + CO2
15. PCl3 + Cl2 PCl5
17. CaH2 + 2H2O Ca(OH)2 + 2H2
19. C3H8 + 5O2 3CO2 + 4H20
As you come in,
The Materials: Remote control Periodic table Pick up an “Intro to Chemical Reactions Investigations”
handout The Plan:
I-Respond Warm-Up – Types of Reactions Practice Quiz Instructions for “Intro to Chemical Reactions
Investigations” Collaborative investigations in the lab
The Assessments: TOMORROW – Types of Chemical Equations Quiz Thursday – Writing and Balancing Equations Quiz Friday – Predicting Products and Balancing Equations Quiz
A.) Synthesis
B.) Decomposition
C.) Combustion
D.) Single Replacement
E.) Double Replacement
1. When grilling burgers with your friends on Saturday evening, your propane tank and gas grill work together to perform the following reaction:
C3H8 + O2 CO2 + H2O
2. If not stored properly, your hydrogen peroxide can cause a mess in your medicine cabinet. Hydrogen peroxide quickly breaks down in the presence of light to produce oxygen gas and hydrogen gas.
A.) Synthesis
B.) Decomposition
C.) Combustion
D.) Single Replacement
E.) Double Replacement
3. The white precipitate formed by acid rain on a marble statue is produced in the following reaction: CaCO3(aq)+H2SO4(aq)CaSO4(s)+H2CO3(aq)
A.) Synthesis
B.) Decomposition
C.) Combustion
D.) Single Replacement
E.) Double Replacement
9-2 Practice Problems (even)
2. CaCO3 CaO + CO2
4. CH3CHO CH4 + CO
6. CaSO3 CaO + SO2
8. C2H6N2 C2H6 + N2
10.MnI2 Mn + I2
12.2Mg + TiCl4 2MgCl2 + Ti
14.Br2 + 2NaI 2NaBr + I2
16.2P + 3Br2 2PBr3
18.H2SO4 + 2KOH K2SO4 + 2H2O
20. 2C6H6 + 15O2 12CO2 + 6H2O
Predicting Products & States of Matter
52. 2Al + 6HCl 2AlCl3 + 3H2
Predicting Products & States of Matter
52. 2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)
56.ZnCl2 + (NH4)2S 2NH4Cl + ZnS
Predicting Products & States of Matter
56.ZnCl2 (aq)+ (NH4)2S(aq) 2NH4Cl(aq) + ZnS(s)
59. HgSO4 + 2NH4NO3 Hg(NO3)2 + (NH4)2SO4
Predicting Products & States of Matter
59. HgSO4(aq) + 2NH4NO3(aq) Hg(NO3)2(aq) + (NH4)2SO4(aq)
60. Fe + CuSO4 FeSO4 + Cu
Predicting Products & States of Matter
60. Fe (s)+ CuSO4 (aq) FeSO4 (aq) + Cu (s)
67. Br2 + 2NaI 2NaBr + I2
Predicting Products & States of Matter
67. Br2 (l) + 2NaI(aq) 2NaBr (aq) + I2 (g)
Colored Pencil Corrections
Al(NO3)3 + NaOH = Al(OH)3 + NaNO3
KClO3 = KCl + O2
H3PO4 + Mg(OH)2 = Mg3(PO4)2 + H2O
NH4NO2 = N2 + H2O
BaCl2 + Na2SO4 = NaCl + BaSO4
Fe2O3 + CO = Fe + CO2
Mg(OH)2 + (NH4)3PO4 = Mg3(PO4)2 + NH3 + H2O
Reactions in Aqueous Solution
More than 70% of earth is covered by water66% of the human body is waterMANY chemical reactions occur in waterOften form solids called precipitates
Remember: Ionic compounds dissociate in water.
Net Ionic Equations
Represent reactions of ionic compounds in aqueous solution by writing complete ionic equations
Remove spectator ions (those appear on both sides of the equation but aren’t in the precipitate)
Leaves a net ionic equation that can be balanced
Chemical Reactions Pre-Lab
Why do I set up the lab with so many aqueous solutions? Rate of Reaction
Temperature – warmer = faster reaction; particles are moving faster
Concentration - # of particles; more particles = faster reaction
State of Matter – dissolved means greater surface area; more surface area = faster reaction
Surface Area - Filings, shot, powder, mossy, etc.; greater surface area = faster reaction
Catalyst – DOES NOT REACT; lowers the activation energy of the reaction