1. Gas Laws
Chapter 11
Section 2

2. Boyle’s Law
Boyle’s law shows the relationship between pressure and volume
The relationship is inverse
Volume pressure
Mathematically: PV = k
k is a constant  

3. Boyle’s Law

4. Using Boyle’s Law When temperature is held constant: P1V1 = P2V2
P1V1 is the initial pressure and volume
P2V2 is the ending pressure and volume

5. Problem 1
A sample of oxygen gas has a volume of mL when its pressure is atm. What will the volume of the gas be at a pressure of atm if the temperature remains constant?
Identify every quantity in the problem with the units

6. Problem Solution P1 = 0.947 atm V1 = 150.0 mL P2 = 0.987 atm V2 = ?
Use Boyle’s law to solve
Answer: 144 mL O2
Work problem on page 370

7. Charles’s Law
Charles’s law show the relationship between volume and temperature
The relationship is direct
Temperature volume
V = kT or V/T = k  

9. Using Charles’s Law When pressure is held constant:
V1 and T1 are initial conditions
V2 and T2 are ending conditions
Temperatures must be in Kelvin to use gas laws (K = °C + 273)

10. Problem 2
A sample of neon gas occupies a volume of 752 mL at 25°C. What volume will the gas occupy at 50°C if the pressure remains constant?
Identify every quantity in the problem with the units

11. Solution V1 = 752 mL T1 = 25°C + 273 = 298 K T2 = 50°C + 273 = 323 K
Use Charles’s law to solve
Answer: 815 mL Ne
Work both problems on page 372

12. Gay-Lussac’s Law
Gay-Lussac’s law shows the relationship between pressure and temperature
The relationship is direct
Temperature pressure
P = kT or P/T = k  

14. Using Gay-Lussac’s Law
When volume is held constant:
P1 and T1 are initial conditions
P2 and T2 are ending conditions
Temperatures must be in Kelvin to use gas laws (K = °C + 273)

15. Problem 3
The gas in a container is at a pressure of 3.00 atm at 25°C. Directions on the container warn the user not to keep it in a place where the temperature exceeds 52°C. What would the gas pressure in the container be at 52°C?
Identify every quantity in the problem with the units

16. Solution P1 = 3.00 atm T1 = 25°C + 273 = 298 K T2 = 52°C + 273 = 325 K
Use Gay-Lussac’s law to solve
Answer: 3.27 atm
Work all three problems on page 374

17. Graphical Representations of the Gas Laws
Boyle’s law Charles’s law Gay-Lussac’s law

18. Combined Gas Law
A gas sample frequently undergoes changes in temperature, pressure, and volume all at the same time.
The amount of gas remains constant
Combined gas law: expresses the relationship between pressure, volume, and temperature of a fixed amount of gas

19. Combined Gas Law
When the amount of the gas is held constant

20. Problem 4
A helium-filled balloon has a volume of 50.0 L at 25°C and 1.08 atm. What volume will it have at atm and 10.0°C?
Identify every quantity in the problem with the units

21. Solution P1 = 1.08 atm T1 = 25°C + 273 = 298 K V1 = 50.0 L
Use the combined gas law to solve

22. Solution
60.0 L He
Work both problems on page 375