1. The Gas Laws
11.2

2. Boyle’s Law
Boyle’s Law – the volume of a fixed mass of gas varies inversely with the pressure at constant temp.
PV = k
You can relate 2 different gases w/ k
P1V1 = P2V2

3. Practice
A sample of O2 gas has a vol of mL when it’s P is atm. What will the vol of the gas be at a P of atm if the T remains constant?
Make sure both P and V units are the same!

4. Practice
A balloon filled with He gas has a vol of 500 mL at a P of 1 atm. The balloon is released and reaches an altitude of 6.5 km, where the P is 0.5 atm. If the T has remained the same, what volume does the gas occupy at this height?

5. Temperature
Absolute zero – the T of °C is given a value of 0 in the Kelvin scale.
K = °C
Charles’ Law = the vol of a fixed mass of gas at constant P varies directly with the Kelvin Temp

6. Charles’ Law
V = kT
V = k T
V1 = V2
T1 = T2

7. Practice
A sample of neon gas occupies a volume of 752 mL at 25°C. What V will the gas occupy at 50°C if the P is constant?
A sample of N2 gas is contained in a piston w/a freely moving cylinder. At 0°C, the V of the gas is 375 mL. To what T must the gas be heated to occupy a V of mL?

8. Gay-Lussac’s Law
The P of a fixed mass of a gas at constant V varies directly with the Kelvin T
P = kT P = k T
Set K equal to get…
P1 = P2
T1 = T2

9. Practice
The gas in a container is at a P of atm at 25°C. Directions on the container warn the user not to keep it in a place where the T exceeds 52°C. What would the P be at 52°C?

10. Practice
At °C, the pressure of a sample of nitrogen is 1.07 atm. What will the pressure be at 205 °C, assuming constant volume.
A sample of He gas has a P of atm at 22 °C. At what Celsius Temp will the He reach a P of 2.00 atm, assuming constant V.

11. The Combined Gas Law
Combines Charles’, Boyle’s, and G-L
CGL – expresses the relationship b/t P, V, and T of a fixed amt of gas
PV = k P1V1 = P2V2
T T T2
T must be in Kelvin!!!!!

12. Practice
A helium Balloon has a volume of L at 25°C and 1.08 atm. What V will it have at atm & 10.0°C?
A mL gas sample at STP is compressed to a V of mL, and the T is increased to 30.0 °C. What is the new P of the gas in Pa?
Complete S.R. on page 375 # 1-5 