1
Overview
Gas Laws—units, laws, etc.
Kinetic Theory—atomic/molecular scale, counting molecules, counting collisions, etc.
Chemical Kinetics
1.
experimental measurements
2.
mechanism or theory of reaction processes
Thermodynamics
1.
the first law—thermochemistry
2.
the second law—entropy, equilibrium, spontaneity
3.
the third law—entropy at 0 K, physical and chemical limits
4.
phase equilibrium
Chapter 1
Newton’s laws
F=ma
F=force in newtons
m=mass in kg
a = acceleration in m/s
2
dx
dE
F
p
−
=
where E
p
=potential energy
Examples of potential energy (stored energy, “energy of position”)
Hook’s law:
E
p
= ½ k x
2
k=force constant
x=spring extension
The force here:
F = - k x
Gravity:
E
p
= mgh
m=mass
g=9.8 m/s
2
h=height
The force here:
F = - m g
Thus potential energy can be associated with force.
Kinetic Energy (energy associated with motion)
E
k
= ½ m u
2
m=mass
u=speed
Force and energy are different.
Units
Energy units:
2
2
1
1
s
m
kg
J
⋅
=
⋅
Force units:
2
1
1
s
m
kg
N
⋅
=
⋅
The challenge is to see how mechanical systems (springs, falling bodies, etc.) exchange
potential and kinetic energy.
And what does this have to do with chemistry? Chemical systems store energy.
But a more
important issue is spontaneity.
A spontaneous process is NOT necessarily exothermic.
(examples?)

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2
Work:
∫
•
=
dl
F
W
W is the work, F is a force, and dl is distance
Note the vector notation here. Direction is very important.
If F is constant, then
θ
cos
⋅
⋅
=
L
F
W
L is the distance through which the force F is applied and the vectors F and L make an angle
θ
with respect to one another.
Note: the units of work are, N m which must be the same as a J.
Work in terms of gases
Energy FLOW
If P2 > P1, E flows from the surroundings into the system, the Gas.
Endothermic
Δ
E
=
E
f
- E
i
>
0
If P2 < P1, E flows from the system into the surroundings
Exothermic
Δ
E
=
E
f
- E
i
<
0
If P1 and P2 are not near each other in value, a process will take place spontaneously, either an
expansion (P1
>
P2) or a compression (P1
<
P2)
Units of pressure, P:
2
2
2
2
s
m
kg
m
s
m
kg
m
N
A
F
P
⋅
=
⎟
⎠
⎞
⎜
⎝
⎛
⋅
=
⇒
=
Here F means force, A means area, N stands for Newton, m is meters, kg is kilograms, and s is
seconds.
This unit of pressure, the Newton per meter squared is also called a Pascal, Pa
2
1
1
m
N
Pa
⋅
=
⋅
The units of work for an expanding gas must be J again.
This is PV
(show this!!)
Types of systems:
Open—allows mass to flow in and out of the system
Closed—allows only energy to flow in and out of the sytem (either work or heat)
Isolated—allows NO mass and NO energy to flow between system and surroundings.
Gas Laws for closed systems:
Gas, P1
Atmospheric Pressure, P2