Ch. 16 Sect. 3: Behaviors of Gases &
Gas Laws
BOYLE’S LAW&
CHARLES’ LAW
Review
__________ results from gas particles __________ with the walls of their container
Pressure is ______ divided by _____ High pressure = _____________ Low pressure = _____________
Measured in units of:•Pascal’s (Pa) •kilopascals (kPa)•atmospheres (atm) •millimeters mercury (mm Hg)
Variables that Affect Gases
There are four variables that we need to consider when looking at the properties of gases:
1. _________________(number of _______________)
2. __________ (number of __________ in a certain area)
3. __________ (amount of __________ it takes up)
4. __________ (average _________ energy of particles)
Robert Boyle (1627-1691, Ireland)
One of the founders of modern chemistry
He made improvements to the construction of an air pump w/the assistance of Robert Hooke; he used this to do experiments on the properties of air
Boyle’s Law originally published in 1662
Boyle’s LawWhat is the relationship between pressure
and volume of a gas?
“The pressure of a fixed amount of gas varies ____________ with the volume of that gas”
OrIf the pressure goes up, the volume goes ____!
This applies as long as the temperature remains constant as well.
Explaining Boyle’s Law
If pressure increases, that means the number of __________ must also be increasing. By decreasing the
volume of a container, the number of collisions will ________
This occurs only if the temperature and amount of gas remain constant Boyle's Law Animation
Boyle’s Law In Action
When applied to a real life situation, we find that the pressure multiplied by the volume is always equal to a ____________ value The product of the initial volume and
pressure will equal the product of the final volume and pressure
P1•V1 = P2•V2
Boyle’s Law Practice Problem 1
If a balloon has a volume of 500 mL at a pressure of 1-atm, and is driven into the mountains at a pressure 0.5-atm, what is the new volume of the balloon?
Givens Formula
Solution
Boyle’s Law Practice Problem 2
A balloon has a volume of 10.0 L at a pressure of 101 kPa. What will the new pressure be when the volume is increased to 23.5 L?
Givens Formula
Solution
More Boyle’s Law Practice Complete the following table using the Boyle’s Law formula.
P1 (kPa) V1 (mL) P2 (kPa) V2 (mL) Work
10 100 25
2 500 8
3 25 50
7 90 180
10 2 75
5 10 100
1000 2 500
250 5 300
ReviewWhat are the variables that affect gases?
1.
2.
3.
4. In Boyle’s Law, which variables
remain constant, and which variables change?
Constants: Variables:
Jacques Charles (1746-1823, French)
Made the first flight of a hydrogen balloon
Inventor—valve to let H out of balloon, hydrometer
Confirmed Ben Franklin’s electrical experiments
1787 discovered Charles’ Law
Charles’s LawWhat is the relationship between
temperature and volume of a gas?
“The volume of a fixed amount of gas varies ________ with the temperature of that gas”
Or…If the temperature goes up, the volume goes
________!
This applies as long as the pressure remains constant as well.
Explaining Charles’s LawIf the temperature
increases, that means the average _______ energy of the particles also increases.
Particles with more
kinetic energy move more quickly and strike the walls of the container more often with more force which causes the volume to ________ (because the walls expand, pressure does not increase)
This occurs only if the pressure and amount of gas remain constant
Charles's Law Animation
Charles’s Law In ActionWhen applied to a real life situation, we
find that the volume divided by the temperature is always equal to a ________ value The quotient of the initial volume and temperature
will equal the quotient of the final volume and temperature
V1 = V2
T1 T2
In order to avoid having negative values, temperatures need to be converted into ___________
° C + 273 = KK – 273 = ° C
Charles’s Law Practice Problem 1
If a balloon has a volume of 500 mL at 20oC, and is heated to 80oC what will its volume become?
Givens Formula
Solution
Charles’s Law Practice Problem 2
If a balloon has a volume of 2.0 L at 25oC, and it’s volume is decreased to 1.9 L, what is the new temperature in degrees Celsius? Assume pressure and amount of gas remains constant.
Givens Formula
Solution
More Charles’ Law Practice
V1 (mL) T1 (K) V2 (mL) T2 (K) Work
100 293 200
50 348 75
220 373 323
375 323 473
400 100 298
100 350 303
274 25 283
283 50 293
Complete the following table using the Charles’s Law formula.