Gas Laws
What are the postulates of the kinetic molecular theory?
A gas is composed of small particles that are in continuous, random motion. The particles in a gas occupy a volume that is extremely small compared with the container. Particle volume is therefore considered to be negligible. The particles in a gas do not impose any forces on one another. Collisions between particles are perfectly elastic. The average kinetic energy of particles in a gas is proportional to the absolute temperature of the gas.
Real-World Application of the Combined Gas Law
Inside a home hot-water tank: the water is heated the pressure and volume increase inside the tank the overflow valve provides a way to release the increased pressure the pressure is allowed to back up in cold-water pipes to take care of increased volume.
What is absolute temperature?
Kelvin
What is Gay-Lussac's Law?
P1/T1 = P2/T2 P=kT pressure and absolute temperature of a fixed quantity of gas are directly proportional under constant volume conditions.
What is the combined gas law?
P1V1/T1 = P2V2/T2 for a fixed quantity of a gas, the pressure varies inversely with volume and temperature varies directly with pressure and with volume
What is Boyle's Law?
P1V1=P2V2 PV=k the pressure and volume of a fixed quantity of a gas are inversely proportional under constant temperature conditions
Equation for Dalton's Law
Pa/PT=na/nT
What is Charles' Law?
V1/T1 = V2/T2 V=kT the volume and absolute temperature of a fixed quantity of gas are directly proportional under constant pressure conditions
What is the Joule-Thomson effect?
When spraying a gas from an aerosol can: the pressure of gas decreases as it goes from being compressed in the container to being released into the atmosphere. the kinetic energies of gas molecules decrease. the gas temperature decreases as it is sprayed.
Gas law calculations must always use ____________ ________________.
absolute temperature
What is k?
constant
If you decreased the volume of a sample of gas by a factor of three while maintaining a constant pressure, how would the absolute temperature of the gas be affected?
decrease threefold
How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same?
decrease to one third of original volume
An automobile tire at 30°C has a pressure of 3.00 atm. Temperature decreases to -5°C. Assume that there is no volume change in the tire. How does the tire pressure change in response to the temperature change?
decreases
As temperature decreases, pressure
decreases
As temperature decreases, volume
decreases
As volume increases, pressure
decreases
If volume is increased, the number of collisions per second
decreases
Temperature and volume have what relationship when pressure and number of moles of gas are constant?
direct linear relationship
Partial pressure refers to pressure of one gas in a mixture of ____________.
gases
An air bubble with a volume of 5.0 mL is released at the bottom of a lake where the pressure is 3.0 atm. When it reaches the surface, the bubble experiences a pressure of 1.0 atm. How will the volume of the air bubble change?
increase
A balloon with a volume of 2.0 L at 25°C is placed in a hot room at 35°C. The pressure on the balloon is constant at 1.0 atm. How does the volume of the balloon change after moving it to the hot room?
increases
As temperature increases, pressure
increases
As temperature increases, volume
increases
As volume decreases, pressure
increases
If temperature is increased, the number of collisions per second
increases
If the number of particles is increased, the number of collisions per second
increases
Pressure and volume have what relationship when temperature and number of moles of gas are constant?
inverse nonlinear relationship
Partial pressure considers the ___________ of a single gas as if it occupied the container by itself.
pressure
Why might a rubber raft burst if it is left in the sun on a summer day?
temperature and pressure increase
What is a partial pressure?
the fraction of the total pressure exerted by a mix of gases that is contributed by an individual gas.
What is Dalton's Law?
the total pressure exerted by a mixture of gases is the sum of the individual partial pressures of the gases in the mixture.
The sum of the partial pressures equals the _______ pressure of the mixture.
total
