1. Boyle’s Law

2. What are the 4 variables that describe a gas phase system?
Volume
Temperature
Pressure
Amount of gas (in moles)

3. Don’t add or remove any gas.
Fixed Mass?
You don’t change the number of moles of gas. That is…
Don’t add or remove any gas.

4. BOYLE - 1662 Temperature and Amount are constant.
Look at relationship between P and V.
What happened when I increased the pressure on the syringe?
As pressure increases, volume decreases.

5. Image From Tiger
Boyle’s Law: 4 step
J-Tube experiments

6. Trial
Pressure (atm)
Volume (cm3) 1
1.00
800 2
2.00
400 3
3.00
267 4
4.00
200

7. Inverse Relationships
Graph of two variables is a ...
Properties:
Relationship is inverse.
Product of the two variables is a constant.
hyperbola

8. Scientists plot data because a picture shows relationships better than lists of numbers.
There are lots of “pictures” that scientists & mathematicians recognize.

9. PressureVolume (atm-cm3)
Trial
Pressure (atm)
Volume (cm3)
PressureVolume (atm-cm3) 1
1.00
800 2
2.00
400 3
3.00
267 4
4.00
200
For a given T and amount, pressure X volume always equals the same number – the product is CONSTANT!

10. Comparison
Pressure Change
Volume Change
Trials 1 & 2
1 to 2
800 to 400
2 to 1
Trials 1 & 3
1 to 3
800 to 267
3 to 1
Trials 1 & 4
1 to 4
800 to 200
4 to 1

11. Boyle’s Law - words
The volume of a sample of gas is inversely proportional to its pressure, at constant temperature.

12. Boyle’s Law - mathematically
P x V = k (constant)
V = k/P or P = k/V
P1V1 = P2V2
For every point on the hyperbola, P x V = the same constant, k