The Gas Phase Flashcards
STP v. Standard condtions
273 K v. 298 K
How does a real gas deviate from an ideal gas?
At high pressures
Low volumes
Low temperatures
What is an ideal gas?
No intermolecular interactions, no volume
Avogadro’s principle
All gases at a constant temperature and pressure occupy volumes that are directly proportional to the number of moles of gas present
Different systems of pressure measurement
1 atm=760 mmHg = 760 torr = 101.325 kPa
As the number of mols of gas increases?
The volume increases in direct proportion
Boyle’s Law
For a given gaseous sample at a constant temperature, the volume of gas is inversely proportional to pressure
Charles’s Law
At constant pressure, volume of gas is proportional to its absolute temperature
Gay-Lussac’s Law
At constant volume, pressure and temperature are proportional
Dalton’s Law of Partial Pressures
When to or more gases that do not chemically interact are found in one vessel, each gas will behave independently of the others
Pressure exerted by one gas will equal pressure if only one gas was in the container
Henry’s Law
Vapor pressure is pressure exerted by evaporated particles above the surface of a liquid
Solubility of gas increases with increasing partial pressure
Kinetic molecular theory
Explains behavior of gas
Assumes:
1.) Gases have negligible volumes
2.)No intermolecular attractions or repulsions
3.)In continuous, random motion undergoin collisions
4.)Collisions are elastic (momentum and kinetic energy conserved)
5.)Average kinetic energy of gas is proportional to absolute temperature of gas and is the same for all gases at a given temperature
How are the speeds of gases defined?
in terms of average molecular speed
What does kinetic energy of a gas particle depend on?
Temperature
Larger molecules move
Slower
Molecules with higher molecular weights diffuse?
Slower
Graham’s Law
Under isothermal and isobaric conditions, rates at which two gases diffuse and effuse are inversely proportional to square roots of their molar masses
Effusion
Flow of gas particles under pressure from one compartment to another through a small opening
When does gases deviate from ideal the most?
At low temperature
High pressure
Low volume
When does gases most act like ideal gases?
High temperature
Low pressure
High volume
At moderately high pressure, what happens to gas volume?
Less
At extremely high pressure, what happens to gas volume?
Size of particles become large compared to distance between them and volume increases
As temperature of gas is reduced toward its condensation point, what happens to volume?
It decreases
At extremely low temperature, what happens to volume?
It increases
