1. Gas Laws
Lesson 3

2. Pressure Pressure Pascal (Pa), 1 Pascal of pressure
e amount of force exerted per unit of area, or P = F/A.
Pascal (Pa),
the SI unit of pressure.
1 Pascal of pressure
amount of force divided by area, one Pascal of pressure is one Newton per square meter or I N/m².

3. Pressure balloon and a bicycle tire
Containers which remain inflated due to collisions of air particles with walls.
pushes the walls of the container outward
More air particles causes more collisions so pressure increases causing it to expand

4. Pressure P F A
Which shoes create the most pressure?

5. Pressure Key Units at Sea Level
At sea level, atmospheric pressure is kPa.
At Earth’s surface, the atmosphere exerts a force of about 101,300 N on every square meter—about the weight of a large truck.

6. Pressure
Barometer
Atmospheric Pressure
Manometer
Contained Pressure

7. Pressure Effect on Boiling Point
When atmospheric pressure increases, the boiling point of a liquid increases.
EX: high altitude cooking, boiling cold water

8. Boyle’s Law Robert Boyle (1627-1691), Boyle’s law,
British scientist, described this property of gases.
Boyle’s law,
if you decrease the volume of a container of gas and hold the temperature constant, the pressure of the gas will increase.
An increase in the volume of the container causes the pressure to drop, if the temperature remains constant.

9. Boyle’s Law
When the volume of a gas decreases, its pressure increases (at constant temp).
As the volume is increased, the pressure will decrease. P V
PV = k
INVERSE

10. Boyle’s Law in Action Application Boyle’s law
we find that the pressure multiplied by the volume is always equal to a constant if the temperature is constant.
You can use the equations
P1V1 = constant = P2V2
to express this mathematically.

11. The Pressure-Temperature Relationship
What happens if you heat an enclosed gas?
The particles of gas will strike the walls of the canister more often.
If the pressure becomes greater than the canister can hold, it will explode.
At a constant volume, an increase in temperature results in an increase in pressure.

12. Charles’s Law Jacques Charles (1746-1823) Charles’s law
French scientist who studied gases.
Charles’s law
the volume of a gas increases with increasing temperature, as long as pressure does not change

13. Charles’ Law
According to Charles’s law, the volume of a gas increases with increasing temperature, (at constant pressure) V T
DIRECT

14. Charles’s Law
As with Boyle’s law, the reverse is true, also.

15. Charles’ Law Charles’s law
can be explained using the kinetic theory of matter.
gas is heated, its particles move faster and faster and its temperature increases.
gas particles move faster, they begin to strike the walls of their container more often and with more force.

16. Charles’ Law
The formula that relates the variables of temperature to volume shows a direct relationship,
V1/T1 = V2/T2,
when temperature is given in Kelvin.
When using Charles’s law, the pressure must be kept constant.

17. Charles’s Law 2 = V2 T1= 25 °C = 298K 25 3 V1= 2 L T2=3 °C= 276K
What would be the resulting volume of a 2.0-L balloon at 25.0C that was placed in a container of ice water at 3.0C?
WORK:
2 = V2
V2 = 2•276/298
V2 = 1.9 L
GIVEN:
T1= 25 °C = 298K
V1= 2 L
T2=3 °C= 276K
V2 = ?

18. Charles’ Law -273°C or 0 K Absolute Zero - Temp at which...
the volume of a gas would equal zero.
all particle motion would stop.
-273°C or
0 K