Download 3/23/2014 1 8 Chemical Equations Chapter Outline Chemical

3/23/2014
8 Chemical Equations
Chapter Outline
8.1 The Chemical Equation
8.2 Writing and Balancing Chemical Equations
8.3 Types of Chemical Equations
8.4 Heat in Chemical Reactions
8.5 Global Warming: The Greenhouse Effects
Flames and sparks result when aluminum foil
is dropped into liquid bromine.
Foundations of College Chemistry, 14th Ed.
Morris Hein and Susan Arena
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Chemical Equations
Chemical Equations
Chemical Equations:
shorthand notation for chemical changes or reactions.
Chemists use chemical equations to:
a. Summarize a chemical reaction by displaying the
substances reacting and forming.
b. Indicate specific amounts of materials consumed or
produced during the reaction.
Reactants: substances consumed during the reaction.
Products: substances formed during the reaction.
aA + bB
cC + dD
Atom balance must be maintained in all chemical reactions.
All atoms from reactants must appear as part of products.
General Structure of Chemical Equations:
1. Reactants and products are separated by an arrow.
Reactants are on the left side of the arrow,
products are on the right.
aA + bB
cC + dD
Reactants
Products
2. Whole number coefficients are placed in front of
substances to balance the atoms in the equation.
The numbers indicate the units of the substance
reacted or formed during the reaction.
The coefficient 1 is not written in a balanced equation.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Chemical Equations
Chemical Equations
General Structure of Chemical Equations:
Symbol Summary
3. Information about the reaction (temperature, time)
may be placed above or below the reaction arrow.
aA + bB
Δ
cC + dD
Δ indicates heat
4. The physical state is written in brackets after the
formula of the substance.
(g) for gas, (l) for liquid, (s) for solid, (aq) for aqueous
a A (s) + b B (l)
c C (g) + d D (s)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Symbol
Significance
Produces (points towards products)
(s)
Solid (written after substance)
(l)
Liquid (written after substance)
(g)
Gas (written after substance)
(aq)
Substance dissolved in an aqueous solution
Δ
Heat is added (above or below reaction arrow)
© 2014 John Wiley & Sons, Inc. All rights reserved.
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Law of Conservation of Mass
Writing and Balancing
Chemical Equations
Law of Conservation of Mass:
the total mass of substances in a chemical reaction
must remain constant.
Balanced chemical equations: contain the same number
of each kind of atom on both sides of the equation.
water
hydrogen + oxygen
100.0 g
11.2 g
88.8 g
100.0 g total of products
reactants
In any chemical reaction:
Mass of reactants = Mass of products
General Method for
Writing and Balancing Chemical Equations
1. Identify the Reaction.
Write a word equation for the reaction.
Δ
mercury(II) oxide
mercury + oxygen
2. Write the unbalanced (skeleton) equation.
Write the correct formula for each substance
HgO
Δ
Hg + O2
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Writing and Balancing Chemical
Equations
Writing and Balancing Chemical
Equations
General Method for
Writing and Balancing Chemical Equations
3. Balance the equation.
a. Count the number of each atom on the reactants and
products side and determine what requires balancing.
Δ
HgO
Hg:
O:
1
1
Hg + O2
Hg:
O:
General Method for
Writing and Balancing Chemical Equations
b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
2 HgO
Hg:
O:
1
2
Δ
2
2
Hg + O2
Hg:
O:
1
2
Now Hg atoms need balancing on the products side.
Oxygen atoms need balancing on the reactants side.
c. Check after adding coefficients that all atoms still
balance. Adjust as needed (a 2 is needed in front of Hg).
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Writing and Balancing Chemical
Equations
Balancing Chemical Equations Practice
General Method for
Writing and Balancing Chemical Equations
Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
d. Do a final check to make sure all atoms now balance
on both sides of the equation.
2 HgO
Hg:
O:
Δ
2 Hg + O2
Hg:
O:
2
2
2
2
Note: always use the smallest whole numbers!
4 HgO
Δ
4 Hg + 2 O2
1. Identify the Reaction.
Write a word equation for the reaction.
magnesium + oxygen
magnesium oxide
2. Write the unbalanced (skeleton) equation.
Write the correct formula for each substance
Mg + O2
MgO
Balanced but incorrect form!
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© 2014 John Wiley & Sons, Inc. All rights reserved.
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Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
3. Balance the equation.
a. Count the number of each atom on the reactants and
products side and determine what requires balancing.
Mg + O2
Mg:
O:
MgO
Mg:
O:
1
2
1
1
Oxygen needs balancing on the products side.
b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
Mg + O2
Mg:
O:
2 MgO
1
2
Mg:
O:
2
2
Mg now needs balancing on the reactants side.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
c. Check after adding coefficients that all atoms still
balance. Adjust as needed (a 2 is needed in front of Mg).
2 Mg + O2
Mg:
O:
2 MgO
2
2
Mg:
O:
2
2
d. Do a final check to make sure all atoms now balance
on both sides of the equation.
1. Identify the Reaction.
Write a word equation for the reaction.
Potassium chlorate
potassium chloride + oxygen
2. Write the unbalanced (skeleton) equation.
Write the correct formula for each substance
KClO3
Δ
KCl + O2
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
3. Balance the equation.
a. Count the number of each atom on the reactants and
products side and determine what requires balancing.
KClO3
Δ
KCl + O2
K:
1
K:
1
Cl:
1
Cl:
1
O:
2
O:
3
Oxygen needs balancing on both sides of the equation.
© 2014 John Wiley & Sons, Inc. All rights reserved.
b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
2 KClO3
K:
Cl:
O:
2
2
6
Δ
KCl + 3 O2
K:
Cl:
O:
1
1
6
The lowest common multiple of 2 and 3 is 6.
Add coefficients as appropriate to make 6 O atoms.
© 2014 John Wiley & Sons, Inc. All rights reserved.
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Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
Write the balanced chemical equation for the reaction
of silver nitrate with hydrogen sulfide to produce
silver sulfide and nitric acid.
c. Check after adding coefficients that all atoms still
balance. Adjust as needed (a 2 is needed in front of KCl).
2 KClO3
K:
Cl:
O:
2
2
6
Δ
2 KCl + 3 O2
K:
Cl:
O:
2
2
6
1. Identify the Reaction.
Write a word equation for the reaction.
silver nitrate + hydrogen sulfide
silver sulfide + nitric acid
2. Write the unbalanced (skeleton) equation.
Write the correct formula for each substance
AgNO3 + H2S
d. Do a final check to make sure all atoms now balance
on both sides of the equation.
Ag2S + HNO3
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for the reaction
of silver nitrate with hydrogen sulfide to produce
silver sulfide and nitric acid.
3. Balance the equation.
Write the balanced chemical equation for the reaction
of silver nitrate with hydrogen sulfide to produce
silver sulfide and nitric acid.
a. Count the number of each atom on the reactants and
products side and determine what requires balancing.
b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
AgNO3 + H2S
Ag2S + HNO3
Ag: 1
Ag: 2
H:
2
H:
1
S:
1
S:
1
NO3: 1
NO3: 1
Note: If polyatomic ions do not change,
they can be balanced as a “unit”.
2 AgNO3 + H2S
Ag:
H:
S:
NO3:
Ag2S + HNO3
2
2
1
2
Ag:
H:
S:
NO3:
2
1
1
1
H and NO3 are now unbalanced.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
c. Check after adding coefficients that all atoms still balance.
Adjust as needed (a 2 is needed in front of HNO3).
Write the balanced chemical equation for the combustion
of butane (C4H10) gas, where carbon dioxide and
water are the only products.
2 AgNO3 + H2S
Ag:
H:
S:
NO3:
2
2
1
2
Ag2S + 2 HNO3
Ag:
H:
S:
NO3:
2
2
1
2
H and NO3 are now balanced.
d. Do a final check to make sure all atoms now balance
on both sides of the equation.
© 2014 John Wiley & Sons, Inc. All rights reserved.
a. C4H10 + 5 O2
4 CO2 + 5 H2O
b. C4H10 + O2
CO2 + H2O
c. 2 C4H10 + 13 O2
8 CO2 + 10 H2O
d. C4H10 + 6.5 O2
4 CO2 + 5 H2O
1. Identify the Reaction.
butane + oxygen
carbon dioxide + water
2. Write the unbalanced (skeleton) equation.
C4H10 + O2
CO2 + H2O
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Balancing Chemical Equations Practice
Balancing Chemical Equations Practice
Write the balanced chemical equation for the combustion
of butane (C4H10) gas, where carbon dioxide and
water are the only products.
3. Balance the equation.
Write the balanced chemical equation for the reaction of
magnesium hydroxide and phosphoric acid to form
magnesium phosphate and water.
C4H10 + 6.5 O2
C:
H:
O:
4
10
13
4 CO2 + 5 H2O
C:
H:
O:
b. Mg(OH)2 + H3PO4
Mg3(PO4)2 + H2O
Mg3(PO4)2 + H2O
c. 3 Mg(OH)2 + H3PO4
4
10
13
d. 3 Mg(OH)2 + 2 H3PO4
Mg3(PO4)2 + H2O
Mg3(PO4)2 + 6 H2O
1. Identify the Reaction.
Atoms balance, but all coefficients must be
whole numbers. Multiply equation by 2.
2 C4H10 + 13 O2
a. 3 Mg(OH)2 + 2 H3PO4
8 CO2 + 10 H2O
magnesium hydroxide + phosphoric acid
magnesium phosphate + water
2. Write the unbalanced (skeleton) equation.
Mg(OH)2 + H3PO4
Mg3(PO4)2 + H2O
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Balancing Chemical Equations Practice
Information in a Chemical Equation
Write the balanced chemical equation for the reaction of
magnesium hydroxide and phosphoric acid to form
magnesium phosphate and water.
3. Balance the equation.
3 Mg(OH)2 + 2 H3PO4
Mg:
H:
O:
PO4:
Mg3(PO4)2 + H2O
3
12
6
2
Mg:
H:
O:
PO4:
3
2
1
2
To balance water, add a coefficient of six.
3 Mg(OH)2 + 2 H3PO4
Mg3(PO4)2 + 6 H2O
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Information from a Chemical Equation
Information from a Chemical Equation
From the chemical equation below, how many moles
of HF can be produced from 2 moles of hydrogen gas?
H2 (g) + F2 (g)
2 HF (g)
For every 1 mol of H2, 2 mol of HF can be produced.
Two moles of H2 could then produce 4 moles of HF.
From the chemical equation below, how many moles of
oxygen are needed to burn 2 molecules of propane (C3H8)?
C3H8 + 5 O2
3 CO2 + 4 H2O
a. 5 molecules of oxygen
b. 6 molecules of oxygen
c. 10 molecules of oxygen
d. 15 molecules of oxygen
For every 1 molecule of propane,
5 molecules of O2 are needed to fully react.
Two molecules of propane would then require
2 x 5 = 10 molecules of oxygen.
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© 2014 John Wiley & Sons, Inc. All rights reserved.
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Types of Chemical Equations
Combination Reactions
Two reactants combine to give a single product.
Reactions are classified into subtypes to aide in predicting
the products of chemical reactions.
A+B
Reactions are classified into five major categories:
1. Combination reactions
2. Decomposition reactions
3. Single displacement reactions
4. Double displacement reactions
5. Oxidation-reduction (redox) reactions (Chapter 17)
AB
where A or B are elements/compounds and
AB is a compound.
Representative Examples
metal + nonmetal
salt
2 Na (s) + Cl2 (g)
2 NaCl (s)
metal oxide + water
metal hydroxide
CaO (s) + H2O (l)
Ca(OH)2 (aq)
Violent reaction occurs when Al and Br2 react to form AlBr3.
2 Al (s) + 3 Br2 (l)
2 AlBr3 (s)
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© 2014 John Wiley & Sons, Inc. All rights reserved.
Decomposition Reactions
Single Displacement Reactions
A single reactant breaks down (decomposes)
into two or more products .
One element (A) reacts with a compound (BC) to replace
one element in the compound, giving a new element (B)
and a different compound (AC).
AB
A+B
Representative Examples
2 PbO2 (s)
Δ
2 PbO(s) + O2 (g)
Metal oxides often decompose when heated.
Carbonates form CO2 when heated.
CaCO3 (s)
CaO (s) + CO2 (g)
H2O2 decomposes to steam (H2O (g)) and O2.
2 H2O2 (l)
2 H2O (g) + O2 (g)
A + BC
B + AC
where A and B are metals and A is more reactive.
or
A + BC
C + AB
where A and C are halogens and A is more reactive.
Example
Zn reacts with HCl, resulting in H2 gas evolution.
Zn (s) + 2 HCl (aq)
ZnCl2 (aq) + H2 (g)
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Activity Series
General Types of Single
Displacement Reactions
Table listing in order of decreasing reactivity
of various elements.
More reactive elements replace less reactive ones.
2 Al (s) + 3 CuCl2 (s)
2 Ag (s) + 3 CuSO4 (s)
2 AlCl3 (aq) + 3 Cu (s)
No Reaction
Where A and B are metals and A is more reactive:
Metal + acid
2 Al (s) + 3 H2SO4 (aq)
Metal + water
Al2(SO4)3 (aq) + 3 H2 (g)
hydrogen + metal hydroxide/oxide
2 Na (s) + 2 H2O (l)
Metal (or halogen) + salt
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hydrogen + salt
2 NaOH (aq) + H2 (g)
metal (or halogen) + salt
Fe (s) + CuSO4 (aq)
Cu (s) + FeSO4 (aq)
Cl2 (g) + 2 KI (aq)
I2 (s) + 2 KCl (aq)
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Single Displacement Reactions
Single Displacement Reactions
Will a reaction occur between Ni and HCl?
If so, write the balanced chemical equation.
Write the reaction (if it occurs) between
the following substances:
Iron metal and a solution of magnesium chloride
Based on the reactivity series, Ni is more reactive
than hydrogen, so a reaction occurs.
Ni (s) + HCl (aq)
H2 (g) + NiCl2 (aq)
Will a reaction occur between Sn and AlCl3?
If so, write the balanced chemical equation.
Based on the reactivity series, Sn is less reactive than Al,
so no reaction occurs.
Sn (s) + AlCl3 (aq)
No Reaction
a. Fe (s) + MgCl2 (aq)
No Reaction
b. Fe (s) + MgCl2 (aq)
FeCl2 (aq) + Mg (s)
Iron is less reactive than Mg, so no reaction occurs.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Double Displacement Reactions
General Types of
Double Displacement Reactions
Two compounds exchange partners with one another
to yield two new compounds.
AB + CD
AD + CB
Physical evidence for a double displacement reaction
include: heat evolution, formation of a precipitate
or gas production.
Acid/Base Neutralization
acid + base
HCl (aq) + NaOH (aq)
salt + water + heat
NaCl (aq) + H2O (l) + heat
Metal Oxide (base) + Acid
Metal oxide + acid
PbI2 precipitates from the reaction of Pb(NO3)2 with KI.
Pb(NO3)2 (aq) + 2 KI (aq)
PbI2 (s) + 2KNO3 (aq)
CuO (s) + 2 HNO3 (aq)
salt + water + heat
Cu(NO3)2 (aq) + H2O (l) + heat
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
General Types of
Double Displacement Reactions
Writing Reaction Equations Practice
Formation of a Precipitate
Write the reaction equation between aqueous solution
of hydroiodic acid and sodium hydroxide.
Product solubilities are based on the table in Appendix V
Insoluble products are indicated by (s)
BaCl2 (aq) + 2 AgNO3 (aq)
2 AgCl (s) + 2 KNO3 (aq)
Gas Formation
H2SO4 (l) + NaCl (s)
NaHSO4 (aq) + HCl (g)
A gas can also form from a secondary reaction
after displacement
2 HCl (aq) + Na2CO3 (aq)
H2CO3 (aq)
2 NaCl (aq) + H2CO3 (aq)
H2O (l) + CO2 (g)
© 2014 John Wiley & Sons, Inc. All rights reserved.
First convert names to chemical formulas
and determine the type of reaction.
HI (acid)/NaOH(base)
Neutralization Reaction
acid + base
HI (aq) + NaOH (aq)
salt + water
NaI (aq) + H2O (l)
Salt formula must charge balance (Na+ and I–)
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Writing Reaction Equations Practice
Write the balanced reaction equation between
aqueous barium chloride and magnesium sulfate.
First convert names to chemical formulas
and determine the type of reaction.
BaCl2/MgSO4
Both compounds are ionic, but not acids or bases.
The reaction is likely a double displacement.
BaCl2 (aq) + MgSO4 (aq)
BaSO4 (s) + MgCl2 (aq)
Based on Appendix V, BaSO4 will precipitate,
providing a driving force for the reaction.
Writing Reaction Equations Practice
Write the balanced reaction equation between
aqueous potassium phosphate and barium chloride.
1. Convert names to formulas
K3PO4/BaCl2
Both compounds are ionic, but not acids or bases.
The reaction is likely a double displacement.
Based on Appendix V, Ba3(PO4)2 will precipitate,
providing a driving force for the reaction
a. K3PO4 (aq) + BaCl2 (aq)
No Reaction
b. K3PO4 (aq) + BaCl2 (aq)
KCl (aq) + Ba3(PO4)2 (aq)
c. 2 K3PO4 (aq) + 3 BaCl2 (aq)
6 KCl (aq) + Ba3(PO4)2 (s)
d. 2 K3PO4 (aq) + 3 BaCl2 (aq)
6 KCl (s) + Ba3(PO4)2 (aq)
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Writing Reaction Equations Practice
Heat in Chemical Reactions Terminology
Write the balanced reaction equation between
aqueous ammonium chloride and sodium nitrate.
1. Convert names to formulas
NH4Cl/NaNO3
Both compounds are ionic.
The reaction is likely a double displacement.
Based on Appendix V, neither compound will precipitate.
a. NH4Cl (aq) + NaNO3 (aq)
No Reaction
b. NH4Cl (aq) + NaNO3 (aq)
NH4NO3 (aq) + NaCl (aq)
c. NH4Cl (aq) + NaNO3 (aq)
NH4NO3(s) + NaCl (aq)
d. NH4Cl (aq) + NaNO3 (aq)
NH4NO3 (aq) + NaCl (s)
Energy transfer and changes accompany
any chemical reaction.
Heat of reaction: quantity of heat actually
produced during a chemical reaction.
Units: kilojoules (kJ) or kilocalories (kcal)
Exothermic reactions: release heat
H2 (g) + Cl2 (g)
2 HCl (g) + 185 kJ
Heat can be treated as a product
Endothermic reactions: absorb heat
N2 (g) + O2 (g) + 181 kJ
2 NO (g)
Heat can be treated as a reactant
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Heat in Chemical Reactions Terminology
Heat in Chemical Reactions Practice
Energy transfer and changes accompany
any chemical reaction.
In the reaction:
H2 (g) + I2 (s) + 12.6 kJ
Heat of reaction: quantity of heat actually
produced during a chemical reaction.
a. 12.6 kJ of energy is absorbed
Units: kilojoules (kJ) or kilocalories (kcal)
b. 25.2 kJ of energy is absorbed
C (s) + O2 (g)
CO2 (g) + 393 kJ
2 HI (g)
When 4 moles of HI are produced:
c. 12.6 kJ of energy is released
d. 25.2 kJ of energy is released
1 mol of C reacts with 1 mol of O2 to provide 1 mol of CO2
and 393 kJ of heat are released.
12.6 kJ are absorbed to form 2 mol of HI.
2 x 12.6 kJ are needed to produce 4 mol of HI.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
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Heat as an Energy Transfer
Vehicle in Nature
Heat as an Energy Transfer
Vehicle in Nature
Photosynthesis: converts energy in the form of light
from the sun into chemical energy (bonds in glucose).
Fossil Fuels: petroleum, coal, and natural gas all release
significant amounts of energy during combustion.
6 CO2 (g) + 6 H2O (l) + 2519 kJ
C6H12O6 + 6 O2 (g)
glucose
Photosynthesis is endothermic:
the needed energy is supplied by sunlight.
CH4 (g) + 2 O2 (g)
CO2 (g) + 2 H2O (g) + 890 kJ
Combustion does not occur at
normal temperatures without a spark.
Activation energy: Amount of energy needed to initiate
a chemical reaction.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Graphical Representations of
Endothermic Reactions
Graphical Representations of
Exothermic Reactions
Reaction Coordinate Diagram
Reaction Coordinate Diagram
Products are at a higher potential energy than reactants.
Activation energy: Amount of energy needed to initiate
a chemical reaction.
Products are at a lower potential energy than reactants.
Activation energy: Amount of energy needed to initiate
a chemical reaction.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Global Warming: The Greenhouse Effect
Global Warming: The Greenhouse Effect
Fossil fuels produce CO2 during combustion.
50 billion tons of CO2 are released into the
atmosphere annually.
Other greenhouse gases also affect the atmosphere.
Concentration of CO2 in the atmosphere.
Methane (CH4) is a very potent greenhouse gas.
Levels of methane have increased over the past century
due to coal mining, agricultural development and cows!
The average global temperature has risen by
0.74 ºC over the past century.
© 2014 John Wiley & Sons, Inc. All rights reserved.
© 2014 John Wiley & Sons, Inc. All rights reserved.
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Global Warming: The Greenhouse Effect
Learning Objectives
How do greenhouse gases warm the atmosphere?
8.1 The Chemical Equation
Greenhouse gases trap heat near Earth’s surface.
1. Solar radiation warms the Earth’s surface.
2. Greenhouse gases absorb some of this heat, which
warms the atmosphere.
Describe the information present in a chemical equation.
8.2 Writing and Balancing Chemical Equations
Write and balance chemical equations.
Greenhouses operate in a
similar fashion, allowing
sunlight in but not the
outflow of heat produced.
© 2014 John Wiley & Sons, Inc. All rights reserved.
8.3 Types of Chemical Equations
Give examples of the following types of reactions:
combination, decomposition, single displacement
and double displacement.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objectives
8.4 Heat in Chemical Reactions
Explain the following terms as they relate to a chemical
reaction: exothermic, endothermic, heat of a reaction
and activation energy.
8.5 Global Warming: The Greenhouse Effect
Recognize CO2 levels are increasing and the effect
greenhouse gases have on warming the atmosphere
near the Earth’s surface.
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10