Chemistry Regents Review
Study Slides
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic Structure
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Subatomic Particles
 protons
 electrons
 neutrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Protons
 positively charged (+).
 1 atomic mass unit ( 1 amu)
 Located in the nucleus
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Neutrons
 no charge (0)
 1 atomic mass unit (1 amu)
 Located in the nucleus
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electrons
 Negatively charged (-)
 No mass (0 or 1/1826th amu of a proton)
 In orbital outside the nucleus
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nucleons
 Particles in the nucleus
 Protons and neutrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic number
 The total number of protons
 Identifies each element
28.0855
Si
14
2–8–4
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Mass number
 protons + neutrons
protons
neutrons
Mass number = 14
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Isotopes
 Atoms of the same element
 Same atomic number (protons)
 Different mass numbers (difference in # of neutrons)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Comparing Two Sodium Isotopes
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic mass
 Weighted average mass of all the naturally
occurring isotopes of an element
 Depends on mass numbers and abundances
of each isotope.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic Models
Earliest Model
Current Model
Hard Sphere
Plum Pudding
Empty Space
Electron Shell
Wave-mechanical
(no structure)
(+ and – all over)
(+ nucleus)
(electrons in orbit)
(e- in specific region)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Buy the entire set at
Survivingchem.com
John Dalton: Solid sphere model
 An atom is uniform throughout
 No internal structure and is indivisible
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
J.J. Thompson: Plum-pudding model
 Cathode ray experiment
 Positive and negative particles spread
throughout entire atom
 Discovered electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ernest Rutherford: Empty space model
 Gold foil experiment
 An atom is mostly empty space
 The nucleus is small, dense and positive
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Neil Bohr: Bohr’s Model
 Electrons in planet-like orbits (shells)
 Each orbit corresponds to the energy of the
electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Wave-mechanical: Current model
 Electrons are in orbitals or “clouds”.
 Work of many scientists over hundreds of years
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Orbital
 a region where electrons are likely to be found
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron Shells
 Energy levels of an atom
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron Configuration
 A way of showing the arrangement of electrons in
an atom
2–8–4
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Interpreting Electron Configuration
28.0855
Si
2–8–4
first second
shell shell
2 e- 8 e-
third
shell
4 e-
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ground State Atom
 Low energy and stable state
 The periodic table configurations
2 – 8 – 4 (Silicon)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Excited State Atom
 High energy and unstable state
28.0855
Si
2–8–4
Ground state
2 – 8 – 3 – 1 Excited state
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron Transition
 An electron absorbs (gains) energy to go from a
low to higher shell (3rd to 4th )
 An electron releases (emits) energy to go from a
high to lower shell (4th to 3rd)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Bright-line spectra (band of colors)
 energy released by an excited electron
dropping to a lower (ground) state
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Bright-line spectra (band of colors)
The mixture consists of Sr and Li
 Lines in the mixture match those of strontium and lithium
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Flame Test
A lab test to identify the metallic ion
in a compound
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types and
Physical Behavior of Matter
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Pure substances
 Elements and compounds
 Matter with fixed composition
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Elements
 Composed of atoms with the same atomic number
 Cannot be decomposed by any method
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Compounds
 Two or more different atoms chemically
bonded in a fixed ratio
 Can be broken down by chemical methods
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Binary Compounds
 Composed of just two different atoms
 Ex. NH3, NaCl, CO2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Mixtures
 Two or more substances physically combined
 Composition can vary (not fixed)
 can be separated by physical methods
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Homogeneous mixtures
 Made by dissolving a salt in water
 Uniform composition
 Aqueous solution (made with water)
 Ex. NaCl(aq), CO2(aq)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Aqueous Solution mixtures
 Made by dissolving a salt in water
 Ex. NaCl(aq), CO2(aq)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Heterogeneous mixtures
 Non uniform composition
 Ex. sand in water
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Particle Diagrams of Matter
Atom X
Element (X2)
Atom Y
Compound (XY)
Mixture (X2 and Y)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Separation of Mixtures
 by physical methods
 filtration, decantation (heterogeneous)
 distillation, chromatography (homogeneous)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Filtration (heterogeneous mixture separation)
 by particle sizes
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Decantation (heterogeneous mixture separation)
 Pouring off layers of liquids
 by density difference
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Distillation (homogeneous)
 Boiling and evaporating of liquids
 by large boiling point difference
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solid Phase
 definite volume, definite shape
 regular geometric arrangement of particles
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Liquid Phase
 definite volume but no definite shape
 particles flow over each other
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Gas Phase
 No definite volume, no definite shape
 Particles expand and fill container
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Endothermic (energy absorbing) phase changes
Melting
Au(s) → Au(l)
Evaporation
H2O(l) → H2O(g)
Sublimation
CO2(s) → CO2(g)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Exothermic (energy releasing) phase changes
Freezing
Au(l) → Au(s)
Condensation
H2O(g) → H2O(l)
Deposition
CO2(g) → CO2(s)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Heating Curve
D
E
A: Solid
C: Liquid
E: Gas
Temperature increases
Kinetic energy (KE) increases
Potential energy (PE) stays constant
B: Solid and Liquid
D: Liquid and Gas
Temp stays constant
KE stays constant
PE increases
Melting Point = 0oC
Boiling Point = 100oC
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
(for 6 minutes)
(for 10 minutes)
Cooling Curve
E
E: Gas
C: Liquid
A: Solid
D
C
Temperature decreases
Kinetic energy (KE) decreases
Potential energy (PE) stays constant
D: Gas and liquid
B: Liquid and Solid
B
A
Freezing Point
Temp stays constant
KE stays constant
PE decreases
= 30oC
Condensation Point = 50oC
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
(for 3 minutes)
(for 7 min.)
Temperature
 A measure of the average kinetic energy (KE)
of particles in a substance
30oC
Higher Temp
Greater KE
20oC
Lower Temp
Lower KE
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Temperature Conversion
T
K=
oC
+ 273
Table T
Table
What is -50oC in Kelvin?
K = -50 + 273 = 223 K
350 K in oC?
oC = K – 273
oC = 350 – 273 = 77oC
Entropy
 Measures randomness or disorder of a system
Increase in temperature = Increase in entropy
H2O(s) at 0oC
Lowest Entropy
Least Random
H2O(l) at 30oC
H2O(g) at 100oC
Highest Entropy
Most Random
Heat
 A form of energy that flows from
High to Low temperature
50oC
Heat
40oC
 measures in Joules or calories
Heat Unit
1 kJ
= 1000 Joules
2 kiloJoules = ____Joules
250 J = ____ kJ
(2 x 1000) = 2000 Joules
250
------- = 0.25 kJ
1000
Heat Problems
 Use Table T Equations
and Table B Constants
to set up and solve heat problems involving water.
Factors that Affect Gas Behavior
Volume
Temperature
(space of container)
(Kinetic energy of particles)
Pressure
(force)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Avogadro’s Law
Gases with the
 same volume
 same temperature
 same pressure
have equal # of molecules
Comparing Two gases
H2
CO2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Kinetic Molecular Theory
(KMT)
 describes behavior of ideal gas particles
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
KMT
 Particles are far apart
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
KMT
 Particles move in constant, random,
straight-line motion
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
KMT
 Particles transfer energy to another
when they collide
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
KMT
 Particles have no attraction to one another
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
KMT
 Particles have no or insignificant volume
too small
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ideal Gas
 Has all KMT characteristics
Real Gases (O2, H2)
 Do not obey all KMT properties
 Deviate from (do not behave exactly like) and
Ideal Gas
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Deviation from an Ideal Gas
Comparing Gases and Conditions
Low molar mass
H2
O2
High molar mass
Low Pressure
0.5 atm
0.8 atm
High Pressure
High Temperature
300 K
273 K
Low Temperature


Deviates Least from
Behaves most like


Deviates Most from
Behaves Least like
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Two Reasons Real Gases Deviate
 Particles of real gases do have volume
 Particles of real gases do attract each other
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
At Constant Temperature
 A gas volume is inversely proportional to its
pressure
As pressure decreases, volume increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
At Constant Pressure
 A gas volume is directly proportional to the
Kelvin temperature
As temperature increases, volume increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
At Constant Volume
 A gas pressure is directly proportional to the
Kelvin temperature
As temperature increases, pressure increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solving Gas Law Problem
Use the Combined Gas Law Equation (Table T).
to set up and solve for unknown.
V1P1
V2P2
------- = -------- Combined Gas Law Equation
. erase whatever is constant
T1
T2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Pressure Conversion
1 atm = 101.3 kPa
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Volume Conversion
1 L = 1000 mL
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Physical Property
 Observe without changing chemical compositions
Ex: melting and boiling points
density, mass
solubility, conductivity
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Physical Changes
 No change in chemical composition
 No new substance is formed
 Most are reversible
Ex: Phase change:
H2O(l) → H2O(s)
Dissolving
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical Property
 Observe by changing chemical composition
Ex: It reacts, it rusts, it burns, it decomposes
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical Change
 A change in chemical composition
 New substances are always formed
Ex: Chemical Reaction
H2O → H2 + O2
Decomposition
The Periodic Table
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Periodic Law
 elements are arranged by increasing atomic numbers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Periods - horizontal rows
 Same period elements = same electron shells
Na and Al both have 3 electron shells
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Groups - vertical columns
 Same group
 Same valance electrons.
 Same chemical reactivity.
Ex: Mg and Ba have similar chemical properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Malleable
 Able to be hammered into a thin sheet.
Au (Gold) is malleable.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ductile
 easily drawn or molded into thin wire.
Cu (copper) is ductile
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Brittle
 Breaks or shatters easily when struck
Sulfur (S) is a brittle element
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Luster
 Shininess of a substance.
Silver (Ag) has luster
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Conductivity
 Able to conduct heat or electrical current.
Copper (Cu) has high electrical and thermal (heat) conductivity.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ionization Energy (IE)
 Energy to remove the most loosely bound e-.
Use Table S to compare
Li 520kJ = Lowest IE (most likely to lose and form +ion)
B 801 kJ
C 1086 kJ = Highest IE (least likely to lose and form +ion)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electronegativity (EN)
 Measures attraction of an atom to electrons.
Use Table S to compare
N 3.0 = Highest EN (most likely to attract or gain and form -ion)
C 2.6
B 2.0 = Lowest EN (least likely to attract or gain and form -ion)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Density
 The mass per unit volume.
 Use Table S to compare
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic Radius
The size of a neutral atom.
Use Table S to compare.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Metal Properties






Majority of the elements
Most are solids (Hg the only liquid metal)
Malleable, luster and ductile
High conductivity
Low electronegativity & Low ionization energy
Lose electrons & form positive (+) ions
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonmetals





Can be a solid, liquid or gas
Brittle and dull
Low conductivity
High electronegativity and high ionization energy
Gain electrons and form negative (-) ions
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Metalloids
 Have properties of both metals and nonmetals.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Diatomic Elements
 Two-atom elements
 Br2, I2, N2, Cl2, H2, O2, F2 (BrINClHOF)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Monatomic Elements
 One-atom elements
 All Noble (Group 18) gases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Group 1 - Alkali metals





1 valence electron
Strongest metallic properties
Francium is the most metallic element
Halide formula = XY
Oxide formula = X2O
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Group 2 - Alkaline Earth Metals
 2 valence electrons
 Halide formula = XY2
 Oxide formula = XO
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Group 3 – 12: Transition Metals
 Form multiple oxidation numbers
 Form colorful compounds
NiCl is greenish color
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Group 17 (Halogens)
 Seven valence e Very reactive, diatomic elements
 Has elements in all three phases at STP
Gases: F2 and Cl2
Liquid: Br2 (the only liquid nonmetal)
Solid : I2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Group 18: Noble Gases
 Full and stable valence shell
 Non reactive
 Monatomic Gases (He, Ne)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electronegativity Trends
 Left to Right: Increases due to
decreasing atomic size
 Top to bottom: Decreases due to
increasing atomic size
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ionization Energy Trends
 Left to Right: Increases due to
decreasing atomic size
 Top to bottom: Decreases due to
increasing atomic size
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Metallic Properties Trend
 Left to Right: decrease
 Top to bottom: increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonmetallic Properties Trend
 Left to Right:
Increases
 Top to bottom: decreases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Atomic Radius Trend
 Left to Right: decrease due to
increase in nuclear charge
 Top to bottom: increases due to
increase in electron shells
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Summary of Trends
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Allotropes
 Different molecular forms of an element
 Different physical and chemical properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Common Allotropes
Phosphorous: Red, Black and White
Oxygen: O2 (air) and O3(Ozone)
Carbon: Diamond, graphite, fullerene
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Oxygen Allotropes
Oxygen: O2 (air) and O3(Ozone)
 Different molecular forms
 Different physical and chemical properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Carbon Allotropes
Diamond, graphite, fullerene
 Different molecular forms
 Different physical and chemical properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Phosphorous Allotropes
Red, Black and White
 Different molecular forms
 Different physical and chemical properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical Bonding
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Why do Atoms Bond?
 to get a full valence shell of electrons,
and become more stable.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Octet Rule
 atoms need 8 electrons in their valance
shell to be stable.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Properties of a Bonded Atom
 Lower energy than that of the unbonded atom.
 More stable than the unbonded atom
 Similar to the nearest noble gas (Group 18)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Potential Energy
 Stored energy in bonds of substances.
 Depends on compositions and structure
of the substance.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Bond Formation
 Bond formation is exothermic (release energy)
H + I → H–I + energy
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Bond Breaking
 Endothermic (absorbs energy)
H– I + energy → H + I
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Intramolecular Forces




Bonding between atoms
Ionic
Covalent
metallic
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ionic bonds: Transfer of electrons
Metal loses e- and become + ion
Nonmetal gains e- and become – ion
Electronegativity difference of 1.7 or greater
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Covalent bonds: sharing of electrons
 Two nonmetal share electrons
 Electronegativity difference is less than 1.7
 Can be polar, nonpolar, or network solid
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Single Covalent bond
H–H
H2
Two shared electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Multiple Covalent bonds
Double O = O O2
Four shared electrons
Triple N ≡ N
N2
Six shared electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Polar Covalent bond
 Unequal sharing of electrons by different nonmetal atoms.
 Electronegativity difference is less than 0 but
greater than 1.7.
 Ex. H2O (water), NH3 (ammonia)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonpolar Covalent bond




Equal sharing of electrons by same nonmetal atoms.
Electronegativity difference is 0.
Found in diatomic (two-atom) molecules
Ex. H2 (hydrogen), O2 (oxygen), F2 (fluorine)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Network Solid Covalent bond
 Found in hard substances with high melting points
 Ex. Diamond (C) and Silicon dioxide (SiO2)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Metallic bond




A force holding atoms in a metallic substance.
Describes as “positive nuclei immersed in sea of
mobile electrons.”
Ex. Ca (calcium), Cu (copper), Fe (iron)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Polar substances
 asymmetrical charge distribution in the molecules
 charges are not evenly distributed
 molecules have + and – ends (dipole)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonpolar substances
 have molecules with symmetrical (even)
charge distribution.
 may contain nonpolar or polar bonds
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonpolar substances with nonpolar bonds
 nonpolar bonds between atoms (same nonmetal)
 nonpolar molecules (symmetrical charge distribution)
All diatomic elements
F2 (fluorine)
H2 (hydrogen)
O2 (oxygen)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nonpolar substances with polar bond
 Polar bonds between atoms (different nonmetal)
 nonpolar molecules (symmetrical charge distribution)
Examples
CH4 (methane)
CO2 (carbon dioxide)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Degree of Bond Polarity
 Describes the extent of + and – charges of a bond or
molecule
 Depends on the electronegativity difference (ED)
between the atoms
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Relative Polarity: Compare ED
KCl
Electronegativity
Difference (ED)
3.2 - 0.8
2.4
Largest ED (KCl)
 most ionic
 most polar
 least covalent
KBr
3.0 – 0.8
2.2
KI
2.7 – 0.8
1.9
Smallest ED (KI)
 least ionic
 least polar
 most covalent
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Summary of Properties of Solids
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Valence Electrons
 electrons in the outermost energy level of an atom
26.981
Al
2–8–3
Al has 3 valence e- (last number).
Use the Periodic Table.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Valence Electrons
 Valence electrons are lost and gain in ionic bonding,
and are shared in covalent bonding.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron-dot Diagrams for Atoms
 symbol of an atom surrounded by dots equal
to the number of valence electrons
F
26.981
S
2–7
K•
••
 F


2–8–8-1
Ne
2–8–6
••
•S•

2–8
••
Ne


K
32.099
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com

18.998
26.981
Electron-dot Diagrams Ions
-1
18.998
F
K+
2–7
2–8–6
••
F

-
••
S


2–8–8-1
S

K
-2
32.099

+1

26.981
2-
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron Dot Diagrams for Ionic Compounds
 must show electron dots for both the +ion and –ions,
and the correct number of each ion.
-
K+
••
S




K+
••
F

potassium sulfide (K2S)

potassium fluoride (KF)
2- K+
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electron-dot Diagrams Covalent Compounds
 must show all shared and unshared valence electrons
for both atoms.
carbon dioxide (CO2)




••
••
O C O


••
••
O =C= O








-

H

H

•• ••
Br Br
 
•• ••
Br – Br
 

••
Br

••
Br


bromine (Br2)

hydrogen bromide (HBr)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Hydrogen Bonding
 A very strong intermolecular force that
exists in highly polar substances
 H2O (water),
 NH3 (ammonia)
 HF (hydrogen fluoride)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Hydrogen Bonding
 Accounts for much higher boiling of water (H2O)
when compared to similar substances (H2S, H2Te)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Hydrogen Bonding
 Accounts for much higher boiling of water (H2O)
when compared to similar substances (H2S, H2Te)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical Formulas
and Equations
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical Formula
 Qualitative and quantitative composition of
pure substances (elements & compounds)
Ex. NaCl , H2O, KNO3
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Counting Atoms
H2SO4
2H 1S 4O
7 Total atoms
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Counting Atoms: Formulas with Parenthesis
(NH4)2O
2N 8H 1O
11 Total atoms
(4 x 2)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Counting Atoms in hydrates:
CuSO4•5H2O
1Cu 1S 10H 9O
5x2
(4O + 5O)
‘21 Total atoms
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types of Chemical Formulas
 Molecular
 Structural
 Empirical
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Molecular formula
 Shows the true composition of a known
substance.
H2O
C2H6
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Structural formula
 Shows arrangement of atoms in a substance
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Empirical formula
 shows atoms in the simplest whole-number ratio.
CH4
P2Cl3
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types of Formulas
Molecular
H2O
C2H6
Structural
Empirical
O
H2O
H
H
H H
I I
H–C–C–H
I I
H H
CH3
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Reducing Molecular to Empirical
 Find the Greatest Common Factor (GCF) to all subscripts
 Divide each subscript of the formula by the GCF
Molecular
GCF:
Empirical Formulas:
NO2
K2S2O4
1
2
NO2
KSO2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
C3H6
3
CH2
Binary Compounds
Magnesium fluoride
Barium oxide
Mg2+F1-
Ba2+O2-
Mg1F2
Ba2O2
MgF2
BaO
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Polyatomic ion (Table E) Compounds
Sodium sulfate
ammonium sulfide
Na1+(SO4)2-
(NH4)1+S2-
Na2(SO4)1
(NH4)2S1
Na2SO4
(NH4)2S
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Compounds with multiple oxidation # atom
Titanium(II) oxide
Titanium(III) oxide
Ti2+O2-
Ti3+O2-
Ti2O2
Ti2O3
TiO
Ti2O3
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Naming Binary compounds
ZnBr2
zinc bromide
SrO
strontium oxide
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Naming Polyatomic ion Compounds
Table E
NaClO3
sodium chlorate
NH4Cl
ammonium chloride
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types of Equations
Chemical change
2H2(g) + O2(g) → 2H2O(l)
Physical change
H2O(l)
Nuclear change
.
220Fr
→
→
4He
H2O(s)
+ 216At
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Chemical equation
 Shows changes in chemical composition
of one more substances
2H2(g) + O2(g)
→
2H2O(l)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types of Chemical reactions




synthesis
decomposition
single replacement
double replacement
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Synthesis
 Two or more substances combine to one
2H2
+ O2 →
2H2O
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Decomposition
 One substance breaks apart
2KClO3 →
2KCl
+
3O2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Single replacement
 A more reactive element replaces
another element of a compound
Zn +
2HCl → ZnCl2 +
H2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Double replacement
 Ions of two solutions switch to produce
a precipitate (solid)
NaCl + AgNO3 → NaNO3 + AgCl
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Law of Conservation
 Atoms, mass, charge and energy are
neither created nor destroyed in a reaction.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Balanced Equations
 Equations that show conservation of atoms and charges.
N2
+
3 H2 → 2 NH3
2N
2N
6H
6H
atoms of reactants = atoms of product
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Unbalanced
Balanced
Li3N
2Li3N
Sum of coefficients = 2
→ Li
+ N2
→ 6Li + N2
+
6
+ 1 = 9
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Unbalanced Ca(OH)2 +
Balanced
Sum
H3PO4 → Ca3(PO4)2 + H2O
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
= 3
+
2
+ 1
+
of coefficients
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
6 = 12
Unbalanced
C3H4 + O2 → CO2 + H2O
Balanced
C3H4 + 4O2 → 3CO2 + 2H2O
Sum of
coefficients
1
+ 4
+ 3
+ 2 = 10
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Moles Interpretations
and Calculations
Gram Atomic Mass
Mass of 1 mole of element = Atomic Mass
107.868
Ag
47
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Gram Formula Mass
 Mass of 1 mole of Compound
 Gram-formula mass = the sum of atomic masses
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Calculating Gram-formula Mass
What is the gram-formula mass of Al2(SO4)3 ?
Gram-formula mass = 2(Al) + 3(S)
numerical setup
+ 12(O)
= 2(27 g) + 3(32 g) + 12(16 g)
Gram-formula mass = 342 g
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Mass from Moles Calculation
Mass = moles x formula mass
What is the mass of 2.5 moles of Al2(SO4)3 ?
Mass =
2.5
x
342 = 855 g
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Moles from Mass Calculation
Mass
Moles = ---------------formula mass
Table T
How many moles are represented in 200. grams of Al2(SO4)3 ?
200.
Moles = -------- = 0.580 mol
342
Percent Composition by Mass
Total mass of an atom
% = ---------------------------- x 100
Formula mass
Table T
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
What is the percent composition of Al, S, and O
in the formula Al2(SO4)3 ?
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Percent Composition of a Hydrate Calculation
Portion of a hydrate’s mass that is due to the mass
of the water (or the anhydrous).
Total mass of H2O
% H2O = --------------------- x 100
Formula mass
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
What is the percent of water in the
hydrate CaCO3  4H2O ?
Find the mass of 4H2O:
8 H = 8(1) = 8 g
72 g H2O
4 O = 4(16) = 64 g
72
% H2O = -------- = 42 %
172
Mole Ratios in Equations
4NH3 +
5O2 →
4NO +
6H2O
Mole ratio of NH3 to O2 is 4 : 5
Mole ratio of NO to H2O is 2 : 3
(reduced from 4 : 6)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Mole-mole Problems - Example
4NH3 + 5O2 → 4NO + 6H2O
How many moles of H2O is produced when
2 moles of NH3 react with excess oxygen?
6 mol H2O
2 mol NH3 x ---------------- = 3 mol H2O
4 mol NH3.
Aqueous Solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solution
a homogeneous mixture
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Aqueous Solution
 A mixture made with water as the solvent
NaCl(s) + H2O(l) → NaCl(aq)
solute
solvent
Aqueous solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Properties of solution





Are homogenous (uniformly mixed)
Are generally clear
Are transparent
Can be colorful (contain transition metal)
Particles will not settle upon standing
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Crystallization
 A process of recovering salt (solute) from a mixture by
evaporating (or boiling) off the liquid (solvent).
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solubility
 Extent to which a substance dissolves.
 Solubility is a physical property.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Table F: Soluble and Insoluble Ions
LiCl (lithium chloride) is soluble
KOH (potassium hydroxide) is soluble
AgCl (silver chloride) is insoluble.
Mg(OH)2 (magnesium hydroxide is insoluble
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Factors that affect solubility
 temperature
 pressure
 nature of solute
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Temperature Effect on Solubility:
Solid solute
Gaseous solute
↑ Temperature ↑Solubility
More KCl(s) will dissolve
in water at 40oC than at 25oC
↑ Temperature ↓Solubility
Fewer O2(g) will dissolve
in water at 40oC than at 25oC
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Pressure Effect on Solubility:
Solid solute
Gaseous solute
Change in Pressure has
no effect on solubility
↑ Pressure ↑Solubility
More O2(g) will dissolve in water
at 0.4 atm than at 0.2 atm.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solubility Curve Table G
.
Solid solutes (ex. KCl, NaNO3)
 Solubility increases as water
temperature increases
Gaseous solutes (ex. NH3, HCl )
 Solubility decreases as water
temperature increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Descriptions of solutions
 Saturated
 Unsaturated
 Supersaturated
- Dilute
. Concentrated
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solubility Curve: Table G
Describing Solutions A, B and C at 60oC.
A is a supersaturated solution
(above the curve)
A
.
B
B is a saturated solution
(on the curve)
C
C is an unsaturated solution
(below the curve)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Solubility Curve: Table G
Comparing the Solubility of Substances at 40oC
A
.
Substance A is the most soluble (highest up).
Solution A is most concentrated
and least dilute
C
Substance C is the least soluble (lowest down)
Solution A is least concentrated
and most dilute
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Concentration
 How much solute is in a given amount of
solution (or solvent)
 Molarity and parts per million
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Molarity (M or mol/L)
 Shows concentration moles of solute
per (for every) liter of the solution.
moles of solute
. Molarity = ---------------------- = mol/L
liter of solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Parts per million (ppm)
 Shows concentration in grams of solute
per (for every) one million parts of the solution.
Grams Solute
ppm = -------------------- x 1000000
Grams Solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Vapor
 A gas form of a substance that is normally a
liquid at STP
.
Ex. Water vapor is a gas form of water.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Vapor Pressure
 The pressure exerted by vapor on the
surface of a liquid.
 Depends on the temperature of the samples
As temperature ↑, Vapor Pressure (VP) ↑
 Any liquid has a higher vapor pressure at
50oC than at 35oC
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Boiling Point (BP
 The temperature of a liquid at which the
vapor pressure equals the atmospheric pressure.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Reading Table H: Vapor Pressure of Liquids
c
.
 At 75oC, ethanol has a vapor pressure
of 85 kPa.
 At atmospheric pressure of 60 kPa,
water will boil at a temperature of 87oC.
 The normal boiling point of propanone
is 56oC.
 Propanone (lowest BP at any temperature)
has the weakest IMF, and ethanoic acid
(highest BP at any temp) has the strongest
IMF of the four liquids.
Effect of Solute
When a solute is dissolved in water to make a solution:
 The Boiling Point of the solution is elevated (increased).
 The Freezing Point of the solution is depressed (decreased).
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
 A solution always a lower freezing point
and a higher boiling point than water
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
 A 2.0 M solution has a lower freezing point and
a higher boiling point than a 1.0 M solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
 A 1.0 M KCl (ionic) solution has a lower freezing
point and a higher boiling point than a
1.0 M C6H12O6 (molecular) solution
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Acids, Bases and Salts
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Arrhenius Acids
 Produce H+ (hydrogen ion, proton) as
the only positive(+) ion in solutions
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Properties of Acids





produce H+ ions
turn litmus red
has pH below 7
phenolphthalein is colorless (no effect)
react with some metals
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Arrhenius Bases
 Produce OH- (hydroxide ion) as
the only negative (-) ion in solutions
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Properties of Bases




produce OH- ions
turn litmus blue
phenolphthalein is pink
has pH above 7
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alternate Theories
 Acids donate protons (H+, hydrogen ion)
 Bases accept protons (H+, hydrogen ion)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Acid–Metal Reaction
 Produces hydrogen gas and a salt.
metal
+ acid
→ hydrogen + salt
 All metals above H2 (Li to Pb) will react with an acid.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
All metals above H2 (Li to Pb) will react
spontaneously with an acid.
Ex:
Zn
+ 2HCl → H2 + ZnCl2
All metals below H2 (Cu to Au) will not react
spontaneously with an acid.
Neutralization Reaction
 When equal number of moles of an
acid and a base react.
Acid + Base → Water + Salt
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Examples of Neutralization reactions
Acid + Base → Water + Salt
HCl
+ KOH → H2O + KCl
H+
+
OH– → H2O (net ionic equation)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Titration
 A neutralization lab used in determining the
unknown concentration or volume of
acid or base solution.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Titration Equation
 Use the Titration Equation on Table T to
setup and solve a neutralization problem.
Macid Vacid = Mbase Vbase
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Relating pH to H+ Concentration
1 value difference in pH = 10 fold difference in H+
A change in solution from:
pH 2 to pH 3 = 10 times decrease in H+ concentration
pH 2 to pH 4 = 100 times decrease in H+ concentration
pH 3 to pH 1 = 100 times increase in H+ concentration
pH 4 to pH 1 = 1000 times increase in H+ concentration
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electrolytes
 Substances that conduct electricity when dissolved in water.
 Aqueous solutions of electrolytes conduct electricity because
they contain mobile ions.
 Acids (Table K), bases (Table L) and salts are electrolytes.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Kinetics and Equilibrium
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Kinetics
 The study of rates and mechanisms of reactions
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Collision Theory
 For a chemical reaction to occur, reacting
particles must collide effectively
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Effective Collision
 Collision of particles with sufficient kinetic energy
and at appropriate orientation (angle)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Activation Energy
 Energy needed to start a reaction
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Catalyst
 increases rate of a reaction by lowering activation
energy (alternate pathway),
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Factors that Increase rate and how.
 Increasing Concentration (↑ frequency of collision)
 Increasing Temperature (↑ energy of particles & collision)
 Increasing Pressure (↑ concentration)
 Increasing Surface Area (exposes more area for reaction)
 Adding Catalyst
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Potential Energy (PE)
 Stored energy in chemical compounds.
 Depends on the composition and structure of a
substance
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Potential Energy Diagram
 A diagram showing changes in energy contents
of substances in a reaction.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
.
Potential Energy (PE) Measurements Substances
(a) PE of the reactants
(b) PE of the products
(c) PE of the activated complex
(no change with catalyst)
(no change with catalyst)
(lower with catalyst)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
.
Differences in Potential Energy Measurements
(d) Heat of reaction, ∆H (b – a )
(e) Activation energy forward reaction (c – a)
(f ) Activation energy for reverse (c – b)
(no change with catalyst)
(lower with catalyst)
(lower with catalyst)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Heat of Reaction (∆H)
 The difference (energy change) between the
PE of the products and the PE of the reactants.
∆H = PE of products
– PE of reactants
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Exothermic Reactions (–∆H)
 Reactants have less energy than products
 Energy is released (or lost) to the surrounding
 Increase in temperature of the surrounding
Mg + 2HCl
→ MgCl2 + H2 + Energy
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Endothermic Reactions (+∆H)
 Reactants have more energy than products
 Energy is absorbed (or gain) from the surrounding
 Decrease in temperature of the surrounding
NH4Cl(s) + Energy → NH4+(aq) + Cl– (aq
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Reference Table I - Heat of Reaction
. All reactions with a –∆H are exothermic (they release energy)
Making 2 moles of Al2O3(s) releases 3351 kJ of energy.
Making 1 mole of Al2O3(s) releases 1675.5 kJ (half the energy)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Reference Table I – Heat of Reactions
All reactions with a +∆H are endothermic (they absorb energy)
Making 2 moles of NO2(g) absorbs 66.4 kJ of energy.
Making 4 moles of NO2(g) absorbs 132.8 kJ (twice the energy)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Equilibrium
 A state of balance between two opposing forces.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
At Equilibrium
 Rates (speed) of forward and reverse reactions are
equal
 Concentration (amount) of reactants and products stay
constant
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Le Chatelier’s Principle
 A chemical or physical process will shift (speeds
up or slows down) in one direction to relieve any
added stress
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Increasing Concentration (Stress)
.
more N2 added
H2 concentration
decreases
forward rate increases
reverse rate decreases
NH3 concentration
increases
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Decreasing Concentration (stress)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Increasing Temperature (Stress)
 Speeds up or favors the endothermic reaction.
 Rate increases in the direction away from heat
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Increasing Pressure (Stress)
 Favors or speeds up a reaction toward the side that
has fewer total moles of substances.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Equilibrium
Graph
reaction at equilibrium
(constant concentration)
Stress (H2)
added
A new equilibrium is reached
(concentrations of H2, NH3
and N2 stay constant, again)
Organic Compounds
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Organic Compounds
 Compounds of carbon ( C )
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Hydrocarbons – Table Q
 Contain only hydrogen and carbon atoms.
 Alkanes, alkenes, and alkynes
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkane hydrocarbons
Each single covalent bond
contains 2 shared electrons
Propane has 10 bonds
or 20 shared electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkene hydrocarbons
..
Propene has 9 bonds
or 18 shared electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkyne hydrocarbons
..
.
Propyne has 8 bonds
or 16 shared electrons
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Functional Groups Table R
Isomers
 Organic compounds with the same molecular formula
but different structural formulas and properties.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Isomers
CH3CH2CH2Br
and CH3CHBrCH3
(2-bromopropane)
(1-bromopropane)
are isomers.
 Same molecular formula.
 Same type and number of atoms.
 Same percent composition.
 Same number of bonds.
 Different compounds
 Different properties
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Isomers
 As the number of C atoms increases, the
number of possible isomers also increases.
Ex: C5H12 has more isomers than C4H10.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkane isomers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkyne isomers
..
Alkene isomers
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alkyne isomers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Halide isomers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alcohols isomers
 The –OH is on different C atoms
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ether and Alcohol isomers
 An ether and alcohol of the same number of C atoms
are always isomers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ester Isomers
..
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Ketone and Aldehyde Isomers
 A ketone and an aldehyde of the same number of
C atoms are always isomers
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Organic Acids
(the two below are not isomers, but learn to
recognize and draw organic acids
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Amines and Amides
(not isomers, but learn to recognize and draw them)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Substitution
 Reactions of alkanes
 H of an alkane is replaced by a halogen
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Addition: Hydrogenation
 A reaction of alkenes
 A double bond is broken up to bond two H atoms
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Addition: halogenation
 A reaction of alkenes
 A double bond is broken up to bond two halogens
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Esterification
Making an ester from an acid and alcohol
..
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Esterification
 Making an ester from an acid and alcohol
..
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Condensation Polymerization
 Joining small molecules by removing water
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Addition Polymerization
 Joining without removing water
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Saponification
 Soap making process
Fat + Base → Soap +
Glycerol
H H H
I I I
H–C–C –C–H
I I I
OH OH OH
1,2,3-propanetriol
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Fermentation
 Ethanol (an alcohol) making process
sugar
C6H12O6
enzyme
zymase
ethanol + carbon dioxide
2C2H5OH +
2CO2
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Combustion
 Burning with oxygen
Organic + oxygen → carbon + water
compound
dioxide
2C8H18
+
25O2 → 16CO2 + 18H2O
Octane
(car fuel)
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Redox and Electrochemistry
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Redox
 Reactions that involve reduction (gain of electron)
and oxidation (loss of electrons).
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Types of Redox Reactions
Synthesis
Decomposition
Single replacement
Simplified redox
.
2H2 + O2 → 2H2O
CaCO3 → Ca
+
CO3
Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
Cu0 + 2Ag+
→ Cu2+ + 2Ag0
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Non-redox reactions
Double Replacement KI + AgNO3 → AgI + KNO3
Ions combining
Na+ + Cl–
→ NaCl
Ionization
H2O → H+ + OH–
-
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
The charge an atom has or appears to have in a reaction.
Oxidation Numbers
Oxidation
numberanofatom
an atom
zero (0)to
, negative
or positive
 The charge
hascan
orbe
appears
have in(-)a reaction.
I
(+).It can be a zero, + or Li has an oxidation number of 0.
Li+ has an oxidation number of +1.
P3– has an oxidation number of -3.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Free element
 Oxidation number of a free element is always zero
Na + Cl2 → NaCl
Na and Cl2 are both free elements.
Their oxidation number is zero: Na0, Cl20
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Compounds
 Oxidation numbers of elements in compounds are given
on the Periodic Table (with few exceptions).
Na + Cl2 → NaCl
compound
Oxidation number of Na in NaCl is +1
22.989
+1
Na
11
-1
35.453
Oxidation number of Cl in NaCl is -1
Cl
17
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Compounds
 The sum of oxidation numbers in compounds must be 0.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Oxidation
 Loss of Electron is Oxidation (LEO)
Mg0 → Mg2+ + 2e–
 Oxidation number of the oxidized substance increases
0 → 2+
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Reduction
 Gain of Electrons is Reduction (GER)
Cl0
+ 2e- → Cl–
 Oxidation number of the reduced substance decreases
0 → -1
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Voltaic Cell




.
Converts chemical energy to electrical energy.
Redox reaction is spontaneous and exothermic.
Oxidation and reduction occur in separate cells.
Battery is a type of a voltaic cell.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electrolytic Cell
 Converts electric energy to chemical energy.
 Redox reaction is nonspontaneous and endothermic.
 Oxidation and reduction occur in one cell
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Electrodes
 Sites on electrochemical cells where oxidation
and reduction take place
 Anode and Cathode
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Anode: oxidation
 Site where electrons are lost (oxidation)
 AnOx (Anode is for Oxidation)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Cathode : reduction
 Site where electrons are gained (reduction)
 RedCat (Reduction occurs at Cathode)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Salt Bridge (Path for ions)
 Path for ions to travel between the
two cells of a voltaic cell, only.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Wire, external conduit (path for electrons)
 Path for electrons to travel from the anode to cathode
 found in both the voltaic and electrolytic cells.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Battery (power supply)
 Supplies energy to force a redox reaction in
electrolytic cells, only.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
LEO
Loss of Electrons is Oxidation
GER:
Gain of Electrons is Reduction
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
An Ox
Anode is the site for Oxidation
Red Cat
Reduction occurs at Cathode
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
APE
Anode is Positive in Electrolytic
CPV
Cathode is Positive in Voltaic
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
VAN
In Voltaic, Anode is Negative
CEN
Cathode in Electrolytic is Negative
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Voltaic Cells: The Electrodes
Zn: anode (+)
 oxidized
 loses e loses mass
(because Zn atoms are
changing to Zn2+ ions)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Voltaic Cells: The Electrodes
Fe: cathode (-)
 gains mass
(because more Fe atoms
are being made from
Fe3+ ions)
Fe3+ ion
 reduced
 gains eCopyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Voltaic Cells: Directions of Electrons and Ions
electrons
.
ions
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Voltaic Cells: Using Table J
More reactive than Zn.
Can replace Zn in this
reaction
Less reactive than Zn.
Cannot replace Zn in this
reaction
Zn is more active
than Fe.
Zn (the more active
of the two metals) is
always the Anode
(oxidized)
Electrolytic Cell: Electroplating
electron
Object (key) on –end of battery
 always the cathode
 gains mass
Battery
 must be present
to provide energy
.
Metal (Ag) on +end of battery
 always the anode
 loses mass
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nuclear Chemistry
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Transmutation: Nuclear reactions
 Changing (converting) one atom to another.
 Particles are absorbed and/or released by the nucleus
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Nuclear Chemistry Particles: Table O
 Use this table to compare mass and charge of particles
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Radioisotopes: Table N
 Any radioactive (unstable) isotope of an element.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alpha emitters
 A radioisotope that decays by releasing an
alpha particle (+α)
See Table N
220 Fr and 238U
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Beta emitters
 A radioisotope that decays by releasing a
beta particle (-β)
Examples (See Table N)
60Co
.
and
14C
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Positron emitters
 A radioisotope that decays by releasing a
beta particle (+β)
Examples (See Table N)
53Fe
and
.
37Ca
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Natural Transmutation
 When a single unstable radioactive nucleus
spontaneously decays (breaks down) to another nucleus.
 alpha decay
 beta decay
 positron emission.
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Alpha Decay (natural transmutation)
238 U
92
.
→
4 He
2
+
234 Th
90
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Beta Decay (natural transmutation)
14 C
6
→
.
0e
-1
+
14 N
7
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Positron Emission (natural transmutation)
37Ca
20
→
.
0e
+1
+
37 K
19
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Artificial Transmutation
 When a stable non-radioactive nucleus is bombarded (hit)
with a particle to produce an unstable (radioactive) nucleus
4He
+
2
.
9 Be
4
→
12 C
6
+
1n
0
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Fission (nuclear energy)
1n
0
+
235 U
92
→
91 Kr
36
+
142 Ba
56
+ 310 n + energy
 Produces greater amount of energy than any
chemical reaction
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Fission (nuclear energy)
1H
1
+
2H
1
→
3 He
2
+ energy
 Produces greater amount of energy than any
fission reactions
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Fusion (nuclear energy)
1n
+
235 U
→
91 Kr
+
142 Ba
+ 31 n + energy
 Produces greater amount of energy than any
chemical reaction
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Completing Nuclear Equation: find X
 Nuclear equation must be balanced
 Top numbers and bottom numbers must be equal on
both sides
Given:
239 Pu
→
4 He
+
X.
Completed:
239 Pu
→
4 He
+
235U.
94
94
2
2
92
92 is the determined atomic
number for X. Use the
Periodic Table to get the correct
element symbol (U).
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Writing a Decay Equation for: Iodine -131
step 1
step 2
Write
Write
nuclide
→ decay mode
+
symbol
symbol
(Use Table N)
(Use Table N and O)
131
53
.
I
→
0e
-1
+
step 3
Determine
Top #, bottom #, and
atom symbol to balance
131
54
Xe
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Half-life
 the time it takes for half of radioisotope to decay
to new atoms.
 Pressure, temperature, or amount of a radioisotope
does not change its half-life.
 Each radioisotope has its own half-life (see Table N).
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Half-life
 Pressure, temperature, or amount of a radioisotope
does not change its half-life.
 Each radioisotope has its own half-life (see Table N).
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Table N
 Use this table to determine and compare
half-lives and decay modes for given
radioisotopes.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Half-life Period
 The number of times a radioisotope decays by half
 The number of half-life periods must be known
(or determined) in order to solve any half-life problem
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Determine Half-life Period from Time
 use the equation below
Length of Time (T)
Half-life Period (n) = ------------------------Half – life (t)
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Determine Half-life Period from Mass
From Original Mass of 50 g to Remaining Mass of 6.25 g
 Cut original mass in half a many times as it takes to get
to the remaining mass
50 g
→
25 g
→ 12.5 g
→
6.25 g
3 cuts in half = 3 half-life periods
Note: Double the mass if going from remaining mass to original mass
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Fraction of Radioisotope Remaining
 Once the number of half period (n) is known or determined
use the equation below.
1
Fraction remaining = ------
2n
.
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Medical Field Radioisotope Tracers
 must have
short half-lives
and be
quickly eliminated
from the body
Radioisotope
Name
Radioisotope Common Applications
Symbol
and Benefits
Iodine-131
131I
Thyroid disorder;
diagnosis and treatment
Technetium-99
99Tc
Cancer tumor diagnosis
60Co
Cancer treatment
56Fe
Blood disorder
treatment
Cobalt-60
Iron-56
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com
Research and Dating Radioisotopes
 typically have
long half-lives
Radioisotope
Name
Radioisotope Common Applications
Symbol
and Benefits
Carbon-14 (alone)
14C
Carbon-14
14C
with
.
Carbon-12
12C
Uranium – 238
238U
with
Lead - 206
206Pb
Tracer for chemical
reactions
Fossil (archeological)
dating
Rock (geological)
dating
Copyright © E3 Scholastic Publishing. All Rights is Reserved. Survivingchem.com