Review Chapter 6 & 7:
General, Organic, & Biological
Chemistry
Janice Gorzynski Smith
Chapter 6 & 7 Concepts
 Energy
 conversions, conservation of energy
 Breaking bonds requires E, forming bonds releases E
 Endothermic & Exothermic Reactions
 Energy diagrams, Activation Energy, heat absorbed or released
 Factors affecting rates of reactions
 Concentration, temperature, catalysts
 Equilibrium
 Equilibrium constant expressions
 Le Chatlier Principle
 States of matter: g, l, s & their properties
 Effect of intermolecular forces on behavior
 Gas laws: combined, ideal, & dalton’s law partial pressure
 Intermolecular forces
 London-Dispersion, Dipole-Dipole, Hydrogen-Bonding
 Relative strength, importance in g, l, s behavior
 Phase Changes
 Navigate a heating/cooling curve
2
 Enthalpy of phase changes
Equations & Conversions
P1V1
=
T1
P2V2
K =
T2
[products]
[reactants] =
1 cal = 4.184 J
PV = nRT
L • atm
R = 0.0821 mol • K
L • mm Hg
R = 62.4
mol • K
Ptotal = PA
[C]c [D]d
[A]a [B]b
+
PB
1,000 cal = 1 kcal
1,000 J = 1 kJ
+
PC
Equations to memorize in red
1 kcal = 4.184 kJ
Energy of Reactions
ENDOTHERMIC
Transition State
E
Energy
required to
break
bonds
Energy
released
as bonds
form
Ea
Ea
ENDOTHERMIC
ΔH
Reactants
Heat + A + B  C + D
Products have weaker bonds and a higher
energy then Reactants.
Heat is absorbed by the system.
ΔE +
ΔH +
Heat absorbed
ΔH
Heat released
Products
EXOTHERMIC
EXOTHERMIC
A + B  C + D + heat
Products have stronger bonds and a lower
energy then Reactants.
Heat is released by the system.
ΔE -
ΔH -
Rates of Reactions
Increase the Rate of a Reaction
Increase Temperature
Greater likelyhood that
particles will have
enough KE to react
Increase Average KE of particles, so more
likely to collide with enough energy to
overcome Ea
Increase Concentration Reactants
Increase the number of collisions per second
Add a Catalyst
Decrease Ea
Same likelyhood rxn will
happen when particles
collide, but more
collisions
Equilibrium & Le Chatlier’s Principle
aA + bB
equilibrium
constant = K =
cC + dD
[products]
[reactants] =
[C]c [D]d
[A]a [B]b
K > 1 products favored K < 1 reactants favored K = 1 equilibrium
A+B
C + D + heat
A + B + heat
C+D
product
reactant
Eq Shift
reactant
Eq Shift
increase

increase

decrease

decrease

product

increase

increase

decrease

decrease

T increase

T increase

T decrease

T decrease
Intermolecular Forces
London Dispersion Forces
Weakest
Dipole-Dipole Forces
Hydrogen Bonds
Ion-Dipole Forces
Strongest
Forces experienced by states of matter
Gas < Liquids < Solids
Increasing Average Kinetic Energy
Physical Properties
Property of s, l, g
Increases
Decreases
Example
Water has a high boiling point because it has H-bonding,
dipole, and dispersion forces. It is close to heptane
(C7H16), a heavier molecule that only experiences
dispersion forces .
The melting point of ionic solids is extremely high
compared to water which experiences all other
intermolecular forces, but not ion-dipole forces. (NaCl is
1074 K and water is 273 K)
Boiling Point
increasing total
intermolecular forces
decreasing total
intermolecular forces
Melting Point
increasing total
intermolecular forces
decreasing total
intermolecular forces
Retention of V &
Shape
Decreasing
Increasing intermolecular intermolecular forces,
forces and decreasing T & and increasing kinetic
P
energy of particles or T &
P
Gases will fill the volume and shape of the container that
holds them, while solids will retain their own shape and
volume regardless of the container.
Surface Tension
with increasing
intermolecular forces
The molecules on the surface have less neighbors (and
therefore less stabilizing intermolecular forces) and so have a
higher potential energy, which the material will try to reduce
with its shape (sphere): water beading.
Viscosity
Vapor Pressure
with decreasing
intermolecular forces
increasing intermolecular decreasing intermolecular Not just a property of liquids, also gases and solids.
Amorphous solids change shape over time because of their
forces and decreasing
forces and increasing
viscosity.
temperature
temperature
Decreasing intermolecular Increasing intermolecular Ether has weaker intermolecular forces than water and a
higher vapor pressure, so it evaporates much faster then
forces and increasing
forces and decreasing
water.
temperature
temperature
Gas Behavior
Non Rigid Container:
Piston
balloon
P1V1
T1
=
P2V2
P constant
V increase w/ T or
# of moles
T2
PV = nRT
Ptotal = PA + PB + PC
Rigid Container:
Closed Flask
V constant
P increase w/ T or
# of moles
Phase Changes
fusion
SOLID
evaporation
LIQUID
freezing
GAS
condensation
deposition
sublimation
endothermic
exothermic
System absorbs energy from surrounds in the form of heat
o Requires the addition of heat
System releases energy into surrounds in the form of heat or light
o Requires heat to be decreased
Phase Changes
gas
TEMPERATURE
l <--> g
liquid
evaporation
or vaporization
ΔHvap
endothermic
s <--> l
solid
fusion
ΔHfus
endothermic
HEAT ADDED