Section 14.1
The Gas Laws
Objectives


State Boyle’s Law, Charles’s Law, and GayLussac’s Law.
Apply the three gas laws to problems
involving the pressure, temperature, and
volume of gases.
Key Terms
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

Boyle’s Law
Charles’s Law
Gay-Lussac’s Law
Kinetic Theory assumptions



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Gas particles do not attract or repel each other
Gas particles are much smaller than the distances
between them
Gas particles are in constant, random motion
No kinetic energy lost when gas particles collide
with each other/walls of container
All gases have same average kinetic energy at
given temperature
Boyle’s Law



If volume of container increased, pressure decreases
(T constant)
 Molecules go farther, impact walls less often
 P less because fewer molecule impacts
If volume of container decreased, pressure increases
(T constant)
 Gas molecules go shorter distance, striking walls
more often
 Increased P because more molecule impacts
Inverse relationship
Boyle’s Mathematical Equation


PV=k (T constant)
Any P x V will give K
 If P1V1 = k AND P2V2 = k
 P1V1 = P2V2
Practice Problem

Page 422, 1-2
Charles’s Law


TEMP must be in Kelvin and P must be
constant!!
If T of container is increased, V increases




Molecules move faster, impact
container walls more often
Gas pressure inside container will
increase
If T of container is decreased, V decreases
Direct mathematical relationship
Charles’s Mathematical Equation


V/T = k (P constant)
Any V/T will give k:
 If
 V1
V1 = k
T1
= V2
T1
T2
And V2 = k
T2
Or V1T2=T1V2
3/23/2016
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http://college.hmco.com/chemistry/shared/media/animations/microscopicillustrationofch.html
Practice Problems

Page 425, 7-8
Gay-Lussac’s Law




Temp MUST be in Kelvin and V is constant!!
If T of container , P 
 Molecules move faster, impact container walls
more often
 P inside container , container has rigid walls
(V constant)
If T of container , P
Direct mathematical relationship
Gay-Lussac's Mathematical Equation


P/T = k (constant V)
Any P = k
T
 So P1 = k
And P2 = k
T1
T2

So P1 = P2
T1
T2
Or P1T2=P2T1
Practice Problems

Page 427, 9-10