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.