* Unlike Ideal Gas
Equation, the "Gas Laws" describe one gas undergoing a change
in conditions.
The Gas Laws are also different from the
Ideal Gas Equation because you do not have to convert any
units except temperature that has to
be in Kelvins.
Combined Gas Law:
P1 V1 = P2 V2
T1 T2
* All of the other gas
laws can be derived from the combined gas law. *
~ Boyle's Law
- describes relationship between pressure
and volume when temperature is constant
- because temperature is constant, it can
be excluded from the equation
- so, equation for Boyle's Law is
____________________________
- pressure & volume are
__________________ proportional
- graph of pressure vs. volume would have
the general shape of
EXAMPLE: A sample of gas occupies 15 liters under 2.1 atm of pressure.
What would the volume of the gas be if the pressure were decreased to
1.2 atm?
(Assume that temperature is constant.)
~ Charles' Law
- describes relationship between volume and
temperature when pressure is constant
- because pressure is constant, it can be
excluded from the equation
- so, equation for Charles' Law is
____________________________
- volume & temperature are ________________
proportional
- graph of volume vs. temperature
would have the general shape of
EXAMPLE: When I purchase a helium balloon at the store
(where the temperature is 25 oC) for my
friend’s birthday, the clerk fills the balloon to a volume of 20.0 liters. When I go outside, the balloon shrinks to a volume
of 17.9 liters. What is the temperature
outside?
~ Gay-Lussac's Law
- describes relationship between pressure and
temperature when volume is constant
- because volume is constant, it can be excluded
from the equation
- so, equation for Gay-Lussac's Law is
_________________________
- pressure & temperature are _______________
proportional
- graph of pressure vs. temperature would have
the general shape of
EXAMPLE: An aerosol can has
an internal pressure of 2.75 atm at room temperature
(25 oC).
What is the pressure in the can if I leave it outside in the sun and the
temperature goes up to 35 oC?