1. Gas Variable Relationships

2. Gas Variables
Pressure
Volume
Temperature
Number of moles

3. Pressure & Volume
As P (h) increases
V decreases

5. Boyle’s Law P a 1/V Constant temperature P x V = constant
Constant amount of gas
P x V = constant

6. Pressure & Volume
As T increases
V increases

7. Charles’s Law 𝑉 𝑇 =𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 **Temperature must be in Kelvin 𝑉∝𝑇
Constant pressure
Constant amount of gas

9. Pressure & Temperature
Constant volume
Constant amount of gas
𝑃∝𝑇
𝑃 𝑇 =𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
**Temperature must be
in Kelvin
As T increases
P increases

10. Gay-Lussac’s Law

11. Avogadro’s Law

12. *video: gas laws

13. Combined Gas Law P1V1 T1 P2V2 T2 = P1V1 n1T1 P2V2 n2T2 = n1=n2
Boyle’s law: PV = c (at constant n and T)
Charles’s law: V = c (at constant n and P) T
Gay-Lussac’s law: P = c (at constant n and P) T
Avogadro’s law: V = c (at constant P and T) n
c = PV nT
P1V1 T1
P2V2 T2 =
P1V1
n1T1
P2V2
n2T2 =
n1=n2

14. Example 1
A gas at 110 kPa and 30.0˚C fills a flexible container with an initial volume of 2.00L. If the temperature is raised to 80.0˚C and the pressure increased to 440 kPa, what is the new volume?

15. Example 2
An unopened bottle of soda contains 46.0 mL of gas confined at a pressure of 1.30 atm and temperature of 5.00˚C. If the bottle is dropped into a lake and sinks to a depth at which the pressure and temperature changes to 1.52 atm and 2.90˚C, what will be the volume of gas in the bottle?

16. Ideal Gas Law PV constant = nT PV (1 atm)(22.414L) = nT
(1 mol)( K)
R = L • atm / (mol • K)
PV = nRT
The conditions 0 0C and 1 atm are called standard temperature and pressure (STP).
Experiments show that at STP, 1 mole of an ideal gas occupies L.