How are the volume, temperature, and
pressure of a gas related?
o What happens if
there is too much
air in this balloon?
o How did the air get
out of the balloon?
Science Standard 8.3.d: Students know
the states of mater depend on molecular
motion.
Science Standard 8.9.e: Construct
appropriate graphs from data and
develop quantitative statements about
the relationship between variables.
pressure: the force of its outward push
divided by the area of the walls of the
container.
directly proportional: a term used to
describe the relationship between two
variables whose graph is a straight line
passing through the point (0,0).
inversely proportional: a term used to
describe the relationship between two
variables whose product is constant.
Measuring Gases
When working with a gas, it is helpful to
know its volume, temperature, and
pressure.
Volume: Because gas particles move and
fill the space available, the volume of a
gas is the same as the volume of its
container.
Measuring Gases
When working with a gas, it is helpful to
know its volume, temperature, and
pressure.
Temperature: a measure of the average
energy of motion of the particles of matter.
The faster the particles are moving, the
greater their energy and the higher the
temperature.
Measuring Gases
When working with a gas, it is helpful to
know its volume, temperature, and
pressure.
 Pressure: the force of its outward push
divided by the area of the walls of the
container. Pressure is often measured in
units of pascals (Pa) or kilopascals (kPa).
It can also be measured in atmospheres
(atm) or millimeters of Mercury (mm Hg).
A Change in Pressure
A punctured basketball deflates as gas
particles begin to escape.
Temperature & Volume – Charles’s Law
When the temperature
of a gas increases at
constant pressure, its
volume increases.
The variables are directly
proportional to each other,
forming a straight line that
passes through the origin.
Temperature & Volume – Charles’s Law
When the temperature
of a gas is decreased
at constant pressure,
the volume decreases.
Algebra & Science
Directly Proportional:
linear
Inversely Proportional:
nonlinear
Temperature & Volume – Charles’s Law
Temperature Conversion:
Kelvin (K) = °C + 273
Example: 0 °C = 273 K
20 °C = 293 K
Equation: V1/T1 = V2/T2
V1 = Volume 1
T1 = Temperature 1
V2 = Volume 2
T2 = Temperature 2
• Charles’ Example 1:
Calculate the decrease in temperature when
2.00 Liters of gas at a temperature of 20 °C is
compressed to 1.00 Liters.
V1/T1 = V2/T2
20 °C = 293 Kelvin
2 L = 1L
293 K
x
2x = 293
x = 146.5 Kelvin
• Charles’ Example 2:
Calculate the increase in volume when 600 mL of
air at a temperature of 20 °C is heated to 60 °C.
V1/T1 = V2/T2
20 °C = 293 Kelvin
60 °C = 333 Kelvin
600 mL = x
293 K
333 K
293x = (600)(333)
293x = 199,800
x = 682 mL
Pressure & Volume –
Boyle’s Law
When the pressure
of a gas at constant
temperature is increased,
the volume of the gas
decreases.
Pressure & Volume –
Boyle’s Law
When the pressure is
decreased, the volume
increases.
Gas pressure is inversely
proportional to volume at
constant temperature.
The product of the two variables is a constant.
Pressure & Volume – Boyle’s Law
Pressure Conversion:
1 atm = 760 mm Hg = 101,325 Pa
Example: 2 atm = 1,520 mm Hg
2 atm = 202,650 Pa
Equation: (P1)(V1) = (P2)(V2)
P1 = Pressure 1
V1 = Volume 1
P2 = Pressure 2
V2 = Volume 2
• Boyle’s Example 1:
 A gas occupies 12.3 liters at a pressure of 40 mm Hg.
What is the volume when the pressure is increased to
60 mm Hg?
(P1)(V1) = (P2)(V2)
(40)(12.3) = (60)(x)
492 = 60x
x = 8.2 liters
• Boyle’s Example 2:
If a gas occupies 3.60 liters at a pressure of 1
atm, what will its volume be at a pressure of
2.50 atm?
(P1)(V1) = (P2)(V2)
(1)(3.60) = (2.50)(x)
3.60 = 2.50x
x = 1.44 liters
Pressure & Temperature
 When a gas is heated, the particles move faster
and collide more often with each other and with
the walls of their container. The pressure of the
gas increases.
 Charles’ Law
A gas occupies 900 mL
at a temperature of 27
°C. What is the
volume at 132 °C?
 Charles’ Law
A gas occupies 900 mL at a temperature of 27 °C.
What is the volume at 132 °C?
V1/T1 = V2/T2
27 °C = 300 Kelvin
132 °C = 405 Kelvin
900 mL = x
300 K
405 K
300x = (900)(405)
300x = 364,500
x = 1,215 mL
 Charles’ Law
What change in
volume results if 60 mL
of gas is cooled from
33 °C to 5 °C?
 Charles’ Law
What change in volume results if 60 mL of gas is
cooled from 33 °C to 5 °C?
V1/T1 = V2/T2
33 °C = 306 Kelvin
5 °C = 278 Kelvin
60 mL = x
306 K
278 K
306x = (60)(278)
306x = 16,680
x = 54.5 mL
 Boyle’s Law
If a gas occupies 1.56
liters at a pressure of 1
atm, what will its
volume be at a
pressure of 3 atm?
 Boyle’s Law
If a gas occupies 1.56 liters at a pressure of 1 atm,
what will its volume be at a pressure of 3 atm?
(P1)(V1) = (P2)(V2)
(1)(1.56) = (3)(x)
1.56 = 3x
x = .52 liters
 #1 & 2 on each side
of the Gas Law
Problems
worksheet
 Finish the
worksheet.
HOMEWORK EXTENSION
 Write a detailed SUMMARY of the section and
complete the UNANSWERED QUESTIONS section of
your notes.
 Choose two of the remaining Depth & Complexity
ICONS in your notes and explain how they relate to this
section.
HOMEWORK EXTENSION
 Write a detailed SUMMARY of the section and
complete the UNANSWERED QUESTIONS section of
your notes.
 Choose two of the remaining Depth & Complexity
ICONS in your notes and explain how they relate to
this section.