Presentation on theme: "II. Gas Laws Topic 10 Gases. A. Boyles Law P V PV = k."— Presentation transcript:
II. Gas Laws Topic 10 Gases
A. Boyles Law P V PV = k
A. Boyles Law b The pressure and volume of a gas are inversely related at constant mass & temp P V PV = k
V T B. Charles Law
V T b The volume and absolute temperature (K) of a gas are directly related at constant mass & pressure
P T C. Gay-Lussacs Law
P T b The pressure and absolute temperature (K) of a gas are directly related at constant mass & volume
= kPV PTPT VTVT T D. Combined Gas Law P1V1T1P1V1T1 = P2V2T2P2V2T2 P 1 V 1 T 2 = P 2 V 2 T 1
V n Avogadros Principle Avogadros Principle b Equal volumes of gases contain equal numbers of moles at constant temp & pressure true for any gas
E. Daltons Law b The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases. P total = P 1 + P When a H 2 gas is collected by water displacement, the gas in the collection bottle is actually a mixture of H 2 and water vapor.
b What is the partial pressure of hydrogen gas in a mixture of hydrogen and helium if the total pressure = 600 mm Hg and the partial pressure of Helium = 439 mm Hg?
GIVEN: P H2 = ? P total = 94.4 kPa P H2O = 2.72 kPa WORK: P total = P H2 + P H2O E. Daltons Law b Hydrogen gas is collected over water at 22.5°C. Find the pressure of the dry gas if the atmospheric pressure is 94.4 kPa. Look up water-vapor pressure on p.899 for 22.5°C. Sig Figs: Round to least number of decimal places. The total pressure in the collection bottle is equal to atmospheric pressure and is a mixture of H 2 and water vapor.
GIVEN: V 1 = 473 cm 3 T 1 = 36°C = 309K V 2 = ? T 2 = 94°C = 367K WORK: Gas Law Problems b A gas occupies 473 cm 3 at 36°C. Find its volume at 94°C. CHARLES LAW T V
GIVEN: V 1 = 100. mL P 1 = 150. kPa V 2 = ? P 2 = 200. kPa WORK: Gas Law Problems b A gas occupies 100. mL at 150. kPa. Find its volume at 200. kPa. BOYLES LAW P V
GIVEN: V 1 = 7.84 cm 3 P 1 = 71.8 kPa T 1 = 25°C = 298 K V2 = ?V2 = ? P 2 = kPa T 2 = 273 K WORK: Gas Law Problems b A gas occupies 7.84 cm 3 at 71.8 kPa & 25°C. Find its volume at STP. P T V COMBINED GAS LAW
GIVEN: P 1 = 765 torr T 1 = 23°C = 296K P 2 = 560. torr T 2 = ? WORK: Gas Law Problems b A gas pressure is 765 torr at 23°C. At what temperature will the pressure be 560. torr? GAY-LUSSACS LAW P T
GIVEN: P gas = ? P total = torr P H2O = 42.2 torr WORK: P total = P gas + P H2O b A gas is collected over water at a temp of 35.0°C when the barometric pressure is torr. What is the partial pressure of the dry gas? Look up water-vapor pressure on p.899 for 35.0°C. Sig Figs: Round to least number of decimal places. E. Daltons Law The total pressure in the collection bottle is equal to barometric pressure and is a mixture of the gas and water vapor.
F. Grahams Law b Diffusion Spreading of gas molecules throughout a container until evenly distributed. b Effusion Passing of gas molecules through a tiny opening in a container