Quiz According to the kinetic theory of gases… What is the formula for Boyle’s Law?
The student will be able to: Explore mixtures and movements of gases in
order to relate total pressure to partial pressure and explain gas diffuses and effuses.
An ideal gas is made up of gas particles that…
a. Have a high massb. Are in random motionc. Have volumed. Can be liquefiede. Attract each other
GasesMixtures and Movements
Gases: Mixtures and Movements• A list of gear for an
expedition to Mount Everest includes climbing equipment, ski goggles, a down parka with a hood, and most importantly compressed-gas cylinders of oxygen. You will find out why a supply of oxygen is essential at higher altitudes.
The contribution each gas in a mixture makes to the total pressure is called the partial pressure exerted by that gas.
Dalton’s Law
In a mixture of gases, the total pressure is the
sum of the partial pressures of the gases.
Dalton’s Law
Dalton’s law of partial pressures states that, at constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases.
Dalton’s Law
Dalton’s LawAnimation 17 Observe the behavior of a mixture of
nonreacting gases.
Three gases are combined in container T.
Dalton’s LawThe partial pressure of oxygen must be 10.67
kPa or higher to support respiration in humans. The climber below needs an oxygen mask and a cylinder of compressed oxygen to survive.
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Graham’s LawDiffusion is the tendency of. molecules to
move toward areas of lower concentration until the concentration is uniform throughout.
Bromine vapor is diffusing upward through the air in a graduated cylinder.
Graham’s LawAfter several
hours, the bromine has diffused almost to the top of the cylinder.
Graham’s LawDuring effusion, a gas escapes through a
tiny hole in its container.
Gases of lower molar mass diffuse and effuse faster than gases of higher molar mass.
Graham’s LawThomas Graham’s Contribution
Graham’s law of effusion states that the rate of effusion of a gas is inversely proportional to the square root of the gas’s molar mass. This law can also be applied to the diffusion of gases.
Graham’s LawComparing Effusion Rates
A helium filled balloon will deflate sooner than an air-filled balloon.
Helium atoms are less massive than oxygen or nitrogen molecules. So the molecules in air move more slowly than helium atoms with the same kinetic energy.
Graham’s LawBecause the rate of effusion is related only to a
particle’s speed, Graham’s law can be written as follows for two gases, A and B.
Graham’s LawHelium effuses (and diffuses) nearly three
times faster than nitrogen at the same temperature.
Graham’s LawAnimation 18 Observe the processes of gas effusion and
diffusion.
Practice!1. What is the partial pressure of oxygen in a
diving tank containing oxygen and helium if the total pressure is 800 kPa and the partial pressure of helium is 600 kPa?
a. 200 kPab. 0.75 kPac. 1.40 104 kPad. 1.33 kPa
Practice!2. A mixture of three gases exerts a pressure of
448 kPa, and the gases are present in the mole ratio 1 : 2 : 5. What are the individual gas pressures?
a. 44 kPa, 88 kPa, and 316 kPab. 52 kPa, 104 kPa, and 292 kPac. 56 kPa, 112 kPa, and 280 kPad. 84 kPa, 168 kPa, and 196 kPa
Practice!3. Choose the correct words for the spaces.
Graham's Law says that the rate of diffusion of a gas is __________ proportional to the square root of its _________ mass.
a. directly, atomicb. inversely, atomicc. inversely, molard. directly, molar
Small Scale-LabPurpose:
To infer diffuse of a gas by observing color changes during chemical reactions.
Be sure to wear :Safety gogglesLab apronGloves
(20 min)
Analysis questions 1-4
(20 MIN)
1. Did we accomplish the objective? Explain.2. Compare and Contrast Partial pressure to
total pressure.3. Compare and contrast Diffusion to
Effusion.4. Explain the purpose or objective of the
Small Scale-Lab5. Was there anything from the lab that
surprised you? Were you already aware that gases can turn certain chemical colors?
Dalton’s Law and Graham’s Law worksheet
Final ExamReview Packet Questions 16-18