Boyles Law 1 atm 4 Liters As the pressure on a gas increases 2 atm 2 Liters As the pressure on a gas increases - the volume decreases Pressure and volume.

Boyle’s Law

1 atm

4 Liters

• As the pressure on a gas increases2 atm

2 Liters

• As the pressure on a gas increases -

the volume decreases

• Pressure and volume are inversely related

Boyle’s Law

Timberlake, Chemistry 7th Edition, page 253

Boyle’s Law

Timberlake, Chemistry 7th Edition, page 253

P1V1 = P2V2

(Temperature is held constant)

P vs. V (Boyle’s law)

At constant temperature and amount of gas, pressuredecreases as volume increases (and vice versa).

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

P1V1 = P2V2

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

DigitalText

DigitalText

Boyle's Law

If n and T are constant, then

PV = (nRT) = kPV = (nRT) = k

This means, for example, that Pressure goes up as Volume goes down.

Robert Boyle(1627 - 1691)

Son of Early of Cork, Ireland.

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

As the volume of the air trapped in the pump isreduced, its pressure goes up, and air is forcedinto the tire.

• As the pressure on a gas increases

• As the pressure on a gas increases -

the volume decreases

• Pressure and volume are inversely related

1 atm

4 Liters

2 atm

2 Liters

• As the pressure on a gas increases -

the volume decreases

• Pressure and volume are inversely related

2 atm

2 Liters

Boyle’s Law Data

Pressure-Volume Relationship

2.5

250

200

150

100

50

0 0.5 1.0 1.5 2.0

Volume (L)

Pre

ssur

e (k

Pa)

(P1,V1)

(P2,V2)

(P3,V3)

P1 x V1 = P2 x V2 = P3 x V3 = 100 L x kPa

P1 = 100 kPaV1 = 1.0 L

P2 = 50 kPaV2 = 2.0 L

P3 = 200 kPaV3 = 0.5 L

P vs. V (Boyle’s Data)

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 404

Pressure vs. Volume for a Fixed Amount of Gas

(Constant Temperature)

0 100 200 300 400 500

Pressure Volume PV

(Kpa) (mL)

100 500 50,000

150 333 49,950

200 250 50,000

250 200 50,000

300 166 49,800

350 143 50,500

400 125 50,000

450 110 49,500

Vol

ume

(mL)

100

200

300

400

500

600

Pressure (KPa)

Pressure vs. Reciprocal of Volume for a Fixed Amount of Gas

(Constant Temperature)

0 100 200 300 400 500

Pressure Volume 1/V

(Kpa) (mL)

100 500 0.002

150 333 0.003

200 250 0.004

250 200 0.005

300 166 0.006

350 143 0.007

400 125 0.008

450 110 0.009

1 /

Vol

ume

(1/L

)

0.002

0.004

0.006

0.008

0.010

Pressure (KPa)

Boyle’s Law Illustrated

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 404

The pressure and volume of a gas are inversely related

•at constant mass & temp

Boyle’s Law

P

V

PV = kCourtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Volume(mL)

Pressure(torr)

P.V(mL.torr)

10.0

20.0

30.0

40.0

760.0

379.6

253.2

191.0

7.60 x 103

7.59 x 103

7.60 x 103

7.64 x 103

Pressure and Volume of a GasBoyle’s LawBoyle’s Law

A quantity of gas under a pressure of 106.6 kPa has a volumeof 380 dm3. What is the volume of the gas at standard pressure, if the temperature is held constant?

P1 x V1 = P2 x V2

(106.6 kPa) x (380 dm3) = (103.3 kPa) x (V2)

V2 = 400 dm3

PV Calculation (Boyle’s Law)

A quantity of gas has a volume of 120 dm3 when confined under a pressure of 93.3 kPa at a temperature of 20 oC. At what pressure will the volume of the gas be 30 dm3 at20 oC?

P1 x V1 = P2 x V2

(93.3 kPa) x (120 dm3) = (P2) x (30 dm3)

P2 = 373.2 kPa

Volume and Pressure

Two-liter flask

One-liter flask

The molecules arecloser together; thedensity is doubled.

The average molecules hits the wall twice as often. The total number of impacts with the wall is doubled and the pressure is doubled.

Bailar, Jr, Moeller, Kleinberg, Guss, Castellion, Metz, Chemistry, 1984, page 101

Volume and Pressure

Two-liter flask

The molecules arecloser together; thedensity is doubled.

The average molecules hits the wall twice as often. The total number of impacts with the wall is doubled and the pressure is doubled.

One-liter flask

Bailar, Jr, Moeller, Kleinberg, Guss, Castellion, Metz, Chemistry, 1984, page 101