Not so long ago, in a chemistry lab far far away…May the FORCE/area be with you

Gas Laws: Boyle’s and Charles’ Law

At the conclusion of our time together, you should be able

to:1. Describe Boyle’s Law with a formula.2. Use Boyle’s Law to determine either a

pressure or volume3. Describe Charles’ Law with a formula.4. Use Charles’ Law to determine either a

temperature or volume

No, I’m not your good little kitty anymore!!!

Boyle’s LawP α 1/VThis means Pressure and

Volume are INVERSELY PROPORTIONAL if moles and temperature are constant (do not change). For example, P goes up as V goes down.

Robert Boyle (1627-1691). Son of Earl of Cork, Ireland.

1 1 2 2PV PV

Boyle’s Law Summary

Pressure is inversely proportional to volume when temperature is held constant.

1 1 2 2PV PV

Boyle’s Law Example

A bicycle pump is a good example of Boyle’s law.

As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire.

Example Page 20:1

P1 V1 P2 V2

(0.947 atm) (0.15 L) (0.987 atm) V2

0.14 Lor 140 mL

Boyle’s Law Practice, Page 20:2

P1 V1 P2 V2

(1 atm) (0.5 L) (0.5 atm) V2

1 L

Kid’s Letters to God:

Charles’ Law

If n and P are constant, then V α T

V and T are directly proportional.

If one temperature goes up, the volume goes up!

Jacques Charles (1746-1823). Isolated

boron and studied gases. Balloonist.

1 2

1 2

V VT T

Charles’s Original Balloon

Modern Long-Distance Balloon

Charles’ Law Summary  The volume of a gas is directly proportional to temperature, and extrapolates to zero at zero Kelvin.

(P = constant)

1 2

1 2

V VT T

Charles’ Law

HittiteInnovations:

Example, Page 23:1

V1

T1

V2

T2

0.075 L

298 K

V2

323 K

0.081 L

Charles’ Law Practice, Page 23:2

V1

T1

V2

T2

2.75 L

293.0 K

2.46 L

T2

262 K or -10.9 oC

Gas Laws: Boyle’s and Charles’ Law

Let’s see if you can:

1. Describe Boyle’s Law with a formula.2. Use Boyle’s Law to determine either a

pressure or volume3. Describe Charles’ Law with a formula.4. Use Charles’ Law to determine either a

temperature or volume

Pass the Clicker!!!

What pressure (in atm) is required to compress 1.00 L of oxygen at 760.0 mm Hg pressure to a volume of 50.0 mL?

1. 150. atm2. .0200 atm3. 50.0 atm4. .0500 atm5. Not listed

A sample of neon gas occupies 266 mL at 25.5oC. At what temperature would the volume of this sample of gas be reduced to half its initial size?

1. -124oC2. 149oC3. 325oC4. 12.8oC5. Not listed

If a sample of oxygen gas has a volume of 3.00 L and a pressure of 0.500 atm, what will be the new volume at STP?

1. 1140 L2. 6.00 L3. 1.50 L 4. .00197 L5. .167 L