II. The Gas LawsBOYLES

CHARLESGAY-

LUSSAC

Ch. 12 - GasesCh. 12 - Gases

A. Boyle’s LawA. Boyle’s LawThe pressure and volume of

a gas are inversely related • at constant mass & temp

P

V

P1V1=P2V2

A. Boyle’s LawA. Boyle’s Law

V

T

B. Charles’ LawB. Charles’ LawThe volume and absolute

temperature (K) of a gas are directly related • at constant mass & pressure

V1 =V2

T1 = T2

B. Charles’ LawB. Charles’ Law

P

T

C. Gay-Lussac’s LawC. Gay-Lussac’s LawThe pressure and absolute

temperature (K) of a gas are directly related • at constant mass & volume

P1 = P2 T1 T2

D. Combined Gas LawD. Combined Gas Law

P1V1

T1

=P2V2

T2

P1V1T2 = P2V2T1

GIVEN:V1 = 100. mL

P1 = 150. kPa

V2 = ?

P2 = 200. kPa

WORK:P1V1T2 = P2V2T1

E. Gas Law ProblemsE. Gas Law ProblemsA gas occupies 100. mL at 150.

kPa. Find its volume at 200. kPa.

BOYLE’S LAWP V

(150.kPa)(100.mL)=(200.kPa)V2

V2 = 75.0 mL

GIVEN:V1 = 473 cm3

T1 = 36°C = 309K

V2 = ?

T2 = 94°C = 367K

WORK:P1V1T2 = P2V2T1

E. Gas Law ProblemsE. Gas Law ProblemsA gas occupies 473 cm3 at 36°C.

Find its volume at 94°C.

CHARLES’ LAWT V

(473 cm3)(367 K)=V2(309 K)

V2 = 562 cm3

GIVEN:P1 = 765 torr

T1 = 23°C = 296K

P2 = 560. torr

T2 = ?

WORK:P1V1T2 = P2V2T1

E. Gas Law ProblemsE. Gas Law ProblemsA gas’ pressure is 765 torr at 23°C.

At what temperature will the pressure be 560. torr?

GAY-LUSSAC’S LAWP T

(765 torr)T2 = (560. torr)(309K)

T2 = 226 K = -47°C

F. STPF. STP

Standard Temperature & PressureStandard Temperature & Pressure

0°C 273 K

1 atm 101.325 kPa-OR-

STP

GIVEN:V1 = 7.84 cm3

P1 = 71.8 kPaT1 = 25°C = 298 KV2 = ?P2 = 101.325 kPaT2 = 273 K

WORK:P1V1T2 = P2V2T1

(71.8 kPa)(7.84 cm3)(273 K)=(101.325 kPa) V2 (298 K)

V2 = 5.09 cm3

E. Gas Law ProblemsE. Gas Law ProblemsA gas occupies 7.84 cm3 at 71.8 kPa &

25°C. Find its volume at STP.

P T VCOMBINED GAS LAW

SolveSolve Divers get “the bends” if they come up

too fast because gas in their blood expands, forming bubbles in their blood. If a diver has 0.05 L of gas in his blood under a pressure of 250 atm, then rises instantaneously to a depth where his blood has a pressure of 50.0 atm, what will the volume of gas in his blood be? Do you think this will harm the diver?

SolveSolveOn hot days, you may have noticed

that potato chip bags seem to “inflate”, even though they have not been opened. If I have a 250 mL bag at a temperature of 19 0C, and I leave it in my car which has a temperature of 600 C, what will the new volume of the bag be?

SolveSolveA gas is heated from 263.0 K to

298.0 K and the volume is increased from 24.0 liters to 35.0 liters by moving a large piston within a cylinder. If the original pressure was 1.00 atm, what would the final pressure be?

SolveSolveA gas with a volume of 4.0L at a

pressure of 205kPa is allowed to expand to a volume of 12.0L. What is the pressure in the container if the temperature remains constant?

SolveSolveA gas has a pressure of 699.0 mm

Hg at 40.0 °C. What is the temperature at standard pressure?

SolveSolve I have added 15 L of air to a

balloon at sea level (1.0 atm). If I take the balloon with me to Denver, where the air pressure is 0.85 atm, what will the new volume of the balloon be?