Download 8 Chemical Equations Chapter Outline Chemical Equations

Slide 1 ___________________________________ 8 Chemical Equations
___________________________________ ___________________________________ ___________________________________ ___________________________________ 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.
Slide 2 ___________________________________ 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
___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 3 ___________________________________ 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.
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ Slide ___________________________________ Chemical Equations
4 ___________________________________ 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.
Slide ___________________________________ Chemical Equations
5 ___________________________________ General Structure of Chemical Equations:
3. Information about the reaction (temperature, time)
may be placed above or below the reaction arrow.
aA + bB
∆
___________________________________ ___________________________________ cC + dD
∆ 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.
Slide ___________________________________ ___________________________________ Chemical Equations
6 ___________________________________ Symbol Summary
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
∆
___________________________________ ___________________________________ ___________________________________ Heat is added (above or below reaction arrow)
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ Slide 7 ___________________________________ Law of Conservation of Mass
___________________________________ Law of Conservation of Mass:
the total mass of substances in a chemical reaction
must remain constant.
___________________________________ ___________________________________ 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
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 8 ___________________________________ ___________________________________ Writing and Balancing
Chemical Equations
___________________________________ Balanced chemical equations: contain the same number
of each kind of atom on both sides of the equation.
___________________________________ General Method for
Writing and Balancing Chemical Equations
___________________________________ 1. Identify the Reaction.
Write a word equation for the reaction.
mercury(II) oxide
∆
___________________________________ mercury + oxygen
___________________________________ 2. Write the unbalanced (skeleton) equation.
Write the correct formula for each substance
∆
HgO
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 9 ___________________________________ Hg + O2
___________________________________ 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.
∆
HgO
Hg:
O:
1
1
___________________________________ Hg + O2
Hg:
O:
1
2
___________________________________ ___________________________________ Oxygen atoms need balancing on the reactants side.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 10 ___________________________________ Writing and Balancing Chemical Equations
___________________________________ 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:
2
2
Hg + O2
Hg:
O:
___________________________________ 1
2
___________________________________ Now Hg atoms need balancing on the products 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.
Slide 11 ___________________________________ ___________________________________ Writing and Balancing Chemical Equations
___________________________________ General Method for
Writing and Balancing Chemical Equations
___________________________________ d. Do a final check to make sure all atoms now balance
on both sides of the equation.
∆
2 HgO
Hg:
O:
2 Hg + O2
Hg:
O:
2
2
___________________________________ ___________________________________ 2
2
___________________________________ Note: always use the smallest whole numbers!
4 HgO
∆
4 Hg + 2 O2
___________________________________ Balanced but incorrect form!
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 12 ___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
___________________________________ 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
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ Slide 13 ___________________________________ Balancing Chemical Equations Practice
___________________________________ 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:
1
2
___________________________________ MgO
Mg:
O:
1
1
___________________________________ Oxygen needs balancing on the products side.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 14 ___________________________________ ___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
___________________________________ b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
Mg + O2
Mg:
O:
1
2
___________________________________ 2 MgO
___________________________________ Mg:
O:
___________________________________ 2
2
Mg now needs balancing on the reactants side.
___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 15 ___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for when
magnesium metal undergoes combustion
to produce magnesium oxide.
___________________________________ 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
2
___________________________________ 2 MgO
___________________________________ Mg:
O:
___________________________________ 2
2
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.
___________________________________ Slide 16 ___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
___________________________________ 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
∆
KCl + O2
17 ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide ___________________________________ ___________________________________ Balancing Chemical Equations Practice
___________________________________ 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
∆
___________________________________ KCl + O2
K:
1
K:
1
Cl:
1
Cl:
1
O:
2
O:
3
Oxygen needs balancing on both sides of the equation.
18 ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide ___________________________________ ___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for the
decomposition of potassium chlorate upon heating
to give oxygen and potassium chloride.
___________________________________ b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
2 KClO3
K:
Cl:
O:
2
2
6
∆
___________________________________ 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.
___________________________________ Slide 19 ___________________________________ Balancing Chemical Equations Practice
___________________________________ 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 KCl).
2 KClO3
K:
Cl:
O:
∆
2
2
6
___________________________________ 2 KCl + 3 O2
K:
Cl:
O:
___________________________________ 2
2
6
___________________________________ 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.
Slide 20 ___________________________________ ___________________________________ 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.
___________________________________ ___________________________________ 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
Ag2S + HNO3
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 21 ___________________________________ ___________________________________ ___________________________________ 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.
___________________________________ a. Count the number of each atom on the reactants and
products side and determine what requires balancing.
___________________________________ Ag2S + HNO3
AgNO3 + H2S
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”.
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ ___________________________________ ___________________________________ Slide 22 ___________________________________ 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.
___________________________________ b. Balance each element sequentially, using whole
numbers. It is often best to balance metals first.
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.
Slide 23 ___________________________________ 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).
2 AgNO3 + H2S
Ag:
H:
S:
NO3:
___________________________________ Ag2S + 2 HNO3
2
2
1
2
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.
Slide 24 ___________________________________ ___________________________________ 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.
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
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 25 ___________________________________ 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.
C4H10 + 6.5 O2
C:
H:
O:
4
10
13
___________________________________ ___________________________________ 4 CO2 + 5 H2O
C:
H:
O:
4
10
13
___________________________________ ___________________________________ Atoms balance, but all coefficients must be
whole numbers. Multiply equation by 2.
2 C4H10 + 13 O2
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 26 ___________________________________ 8 CO2 + 10 H2O
___________________________________ Balancing Chemical Equations Practice
___________________________________ Write the balanced chemical equation for the reaction of
magnesium hydroxide and phosphoric acid to form
magnesium phosphate and water.
a. 3 Mg(OH)2 + 2 H3PO4
b. Mg(OH)2 + H3PO4
___________________________________ Mg3(PO4)2 + H2O
___________________________________ Mg3(PO4)2 + H2O
c. 3 Mg(OH)2 + H3PO4
d. 3 Mg(OH)2 + 2 H3PO4
Mg3(PO4)2 + H2O
___________________________________ Mg3(PO4)2 + 6 H2O
1. Identify the Reaction.
___________________________________ magnesium hydroxide + phosphoric acid
magnesium phosphate + water
2. Write the unbalanced (skeleton) equation.
Mg3(PO4)2 + H2O
Mg(OH)2 + H3PO4
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 27 ___________________________________ ___________________________________ Balancing Chemical Equations Practice
___________________________________ 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.
Slide 28 ___________________________________ Information in a Chemical Equation
___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 29 ___________________________________ 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.
___________________________________ ___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 30 ___________________________________ Information from a Chemical Equation
___________________________________ 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.
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ Slide 31 ___________________________________ Types of Chemical Equations
___________________________________ Reactions are classified into subtypes to aide in predicting
the products of chemical reactions.
___________________________________ 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)
___________________________________ ___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 32 ___________________________________ Combination Reactions
___________________________________ Two reactants combine to give a single product.
A+B
AB
where A or B are elements/compounds and
AB is a compound.
___________________________________ Representative Examples
___________________________________ metal + nonmetal
2 Na (s) + Cl2 (g)
metal oxide + water
CaO (s) + H2O (l)
salt
___________________________________ 2 NaCl (s)
metal hydroxide
___________________________________ Ca(OH)2 (aq)
Violent reaction occurs when Al and Br2 react to form AlBr3.
2 Al (s) + 3 Br2 (l)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 33 ___________________________________ 2 AlBr3 (s)
___________________________________ Decomposition Reactions
___________________________________ A single reactant breaks down (decomposes)
into two or more products .
___________________________________ AB
A+B
Representative Examples
2 PbO2 (s)
∆
___________________________________ 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)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 34 ___________________________________ Single Displacement Reactions
___________________________________ 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).
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)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 35 ___________________________________ ZnCl2 (aq) + H2 (g)
___________________________________ Activity Series
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
___________________________________ ___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 36 ___________________________________ General Types of Single
Displacement Reactions
___________________________________ Where A and B are metals and A is more reactive:
Metal + acid
2 Al (s) + 3 H2SO4 (aq)
Metal + water
___________________________________ hydrogen + salt
Al2(SO4)3 (aq) + 3 H2 (g)
___________________________________ hydrogen + metal hydroxide/oxide
2 Na (s) + 2 H2O (l)
Metal (or halogen) + 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)
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ ___________________________________ Slide 37 ___________________________________ Single Displacement Reactions
___________________________________ Will a reaction occur between Ni and HCl?
If so, write the balanced chemical equation.
___________________________________ Based on the reactivity series, Ni is more reactive
than hydrogen, so a reaction occurs.
Ni (s) + HCl (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
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 38 ___________________________________ H2 (g) + NiCl2 (aq)
___________________________________ ___________________________________ Single Displacement Reactions
___________________________________ Write the reaction (if it occurs) between
the following substances:
Iron metal and a solution of magnesium chloride
___________________________________ ___________________________________ 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.
Slide 39 ___________________________________ ___________________________________ 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.
___________________________________ ___________________________________ ___________________________________ PbI2 precipitates from the reaction of Pb(NO3)2 with KI.
Pb(NO3)2 (aq) + 2 KI (aq)
___________________________________ PbI2 (s) + 2KNO3 (aq)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 40 ___________________________________ General Types of
Double Displacement Reactions
___________________________________ Acid/Base Neutralization
acid + base
___________________________________ salt + water + heat
HCl (aq) + NaOH (aq)
___________________________________ NaCl (aq) + H2O (l) + heat
___________________________________ Metal Oxide (base) + Acid
Metal oxide + acid
CuO (s) + 2 HNO3 (aq)
Cu(NO3)2 (aq) + H2O (l) + heat
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 41 ___________________________________ salt + water + heat
___________________________________ ___________________________________ General Types of
Double Displacement Reactions
___________________________________ Formation of a Precipitate
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)
42 ___________________________________ H2O (l) + CO2 (g)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide ___________________________________ ___________________________________ Writing Reaction Equations Practice
___________________________________ Write the reaction equation between aqueous solution
of hydroiodic acid and sodium hydroxide.
___________________________________ 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–)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 43 ___________________________________ 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.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 44 ___________________________________ ___________________________________ 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)
d. 2 K3PO4 (aq) + 3 BaCl2 (aq)
45 ___________________________________ 6 KCl (aq) + Ba3(PO4)2 (s)
___________________________________ 6 KCl (s) + Ba3(PO4)2 (aq)
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide ___________________________________ ___________________________________ Writing Reaction Equations Practice
___________________________________ 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)
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ ___________________________________ Slide 46 ___________________________________ Heat in Chemical Reactions Terminology
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.
Slide 47 ___________________________________ Heat in Chemical Reactions Terminology
___________________________________ 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)
___________________________________ C (s) + O2 (g)
CO2 (g) + 393 kJ
___________________________________ 1 mol of C reacts with 1 mol of O2 to provide 1 mol of CO2
and 393 kJ of heat are released.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 48 ___________________________________ ___________________________________ Heat in Chemical Reactions Practice
___________________________________ In the reaction:
H2 (g) + I2 (s) + 12.6 kJ
2 HI (g)
___________________________________ When 4 moles of HI are produced:
___________________________________ a. 12.6 kJ of energy is absorbed
b. 25.2 kJ of energy is absorbed
___________________________________ c. 12.6 kJ of energy is released
d. 25.2 kJ of energy is 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.
___________________________________ Slide 49 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).
___________________________________ 6 CO2 (g) + 6 H2O (l) + 2519 kJ
___________________________________ ___________________________________ C6H12O6 + 6 O2 (g)
glucose
___________________________________ Photosynthesis is endothermic:
the needed energy is supplied by sunlight.
___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 50 ___________________________________ Heat as an Energy Transfer
Vehicle in Nature
___________________________________ Fossil Fuels: petroleum, coal, and natural gas all release
significant amounts of energy during combustion.
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.
Slide 51 ___________________________________ ___________________________________ Graphical Representations of Endothermic Reactions ___________________________________ Reaction Coordinate Diagram
___________________________________ ___________________________________ ___________________________________ ___________________________________ Products are at a higher potential energy than reactants.
Activation energy: Amount of energy needed to initiate
a chemical reaction.
© 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ Slide 52 ___________________________________ Graphical Representations of
Exothermic Reactions ___________________________________ Reaction Coordinate Diagram
___________________________________ ___________________________________ ___________________________________ ___________________________________ 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.
Slide 53 ___________________________________ ___________________________________ Global Warming: The Greenhouse Effect
___________________________________ Fossil fuels produce CO2 during combustion.
50 billion tons of CO2 are released into the
atmosphere annually.
___________________________________ Concentration of CO2 in the atmosphere.
___________________________________ ___________________________________ ___________________________________ The average global temperature has risen by
0.74 ºC over the past century.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 54 ___________________________________ ___________________________________ Global Warming: The Greenhouse Effect
___________________________________ Other greenhouse gases also affect 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!
___________________________________ ___________________________________ ___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 55 ___________________________________ Global Warming: The Greenhouse Effect
How do greenhouse gases warm the atmosphere?
___________________________________ 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.
___________________________________ ___________________________________ ___________________________________ Greenhouses operate in a
similar fashion, allowing
sunlight in but not the
outflow of heat produced.
© 2014 John Wiley & Sons, Inc. All rights reserved.
Slide 56 ___________________________________ ___________________________________ ___________________________________ Learning Objectives
___________________________________ 8.1 The Chemical Equation
Describe the information present in a chemical equation.
___________________________________ 8.2 Writing and Balancing Chemical Equations
___________________________________ Write and balance chemical equations.
___________________________________ 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.
Slide 57 ___________________________________ ___________________________________ 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.
___________________________________ © 2014 John Wiley & Sons, Inc. All rights reserved.
___________________________________ ___________________________________