1. 10.7 – NOTES Ideal Gas Laws

2. IV. The Ideal Gas Law describes behavior of an ideal gas in terms of P, V, T, and n

3. A. Real versus ideal gases
* particles have volume
*subject to intermolecular forces
*actual experimental measurements show behavior
*closely resembles ideal behavior
Ideal:
* particles take up no space
*no intermolecular/attractive forces
* follows the gas laws under ALL conditions of T & P

4. At what conditions do the gas laws NOT work well?
Extremely high pressures and low temperatures  close to condensation point
Polar gas molecules (H2O due to increased intermolecular forces)
Very large molecules (butane due to larger actual volume than smaller particles)

5. B. Ideal Gas Law PV = nRT
Describes the physical behavior of an ideal gas in terms of P, V, T, and # moles present (n);
R = ideal gas constant – an experimentally determined constant whose value in the ideal gas equation depends on the units that are used for pressure – L•atm/mol•K

7. Example: 1. Calculate the number of moles if a gas occupies a volume of 3.0L at 1.50 atm and 300. K.
PV = nRT
n = PV/RT
n = PV = (1.50)(3.0) n = 0.18mol
RT (0.0821)(300)

8. 2. Determine the temperature (°C), given 2. 49 moles of a gas in a 1
2. Determine the temperature (°C), given 2.49 moles of a gas in a 1.00 L vessel at a pressure of 1073 torr.
PV = nRT
1073 torr x ______1 atm______ = 1.41 atm
760 torr
T = PV = (1.41)(1.00) T = 7 K = -266°C
nR (0.0821)(2.49)

9. 3. Find the volume of 0.323moles of a gas at 265K and 0.900atm.
PV = nRT
V = nRT = (0.323)(0.0821)(265) V =7.81 L
P (0.900)