Ch. 14: The Behavior of Gases. Chemistry 14.1. 14.1 Properties of Gases compressibility; factors that affect gas pressure 14.2 The Gas Laws Boyle, Charles, Gay-Lussac, combined 14.3 Ideal Gases ideal gas law; ideal gas constant; real gases
14.1 Properties of Gasescompressibility; factors that affect gas pressure
14.2 The Gas LawsBoyle, Charles, Gay-Lussac, combined
14.3 Ideal Gasesideal gas law; ideal gas constant; real gases
14.4 Gases: Mixtures and Movements (SKIP)Dalton’s law of partial pressure; Graham’s law of effusion
The amount of gas, volume, and temperature are factors that affect gas pressure.
Amount of Gas
If the gas pressure increases until it exceeds the strength of an enclosed, rigid container, the container will burst.
1. Compared to liquids and solids, gases are easily compressed because the particles in a gas
2. Gas pressure is affected by
3. For gases, the SI units for volume (V), pressure (P), and temperature (T) are, respectively,
When a gas is heated at constant volume, the pressure increases.
A pressure cooker demonstrates Gay-Lussac’s Law.
Weather balloons carry data-gathering instruments high into Earth’s atmosphere. At an altitude of about 27,000 meters, the balloon bursts.
Gases: relationship between pressure, volume, temperature, and number of molesBoyle’s Law: pressure is inversely proportional to volume as pressure goes up; volume goes downCharles’ Law: volume is directly proportional to temperature as volume goes up; temperature goes upGay-Lussac’s Law: pressure is directly proportional to temperatureCombined Gas Law:
1. If the volume of a gas in a container were reduced to one fifth the original volume at constant temperature, the pressure of the gas in the new volume would be
2. A balloon appears slightly smaller when it is moved from the mountains to the seashore at constant temperature. The best gas law to explain this observation would be
3. At 46°C and 89 kPa pressure, a gas occupies a volume of 0.600 L. How many liters will it occupy at 0°C and 20.8 kPa?
Solid carbon dioxide, or dry ice, doesn’t melt. It sublimes. Dry ice can exist because gases don’t obey the assumptions of kinetic theory under all conditions. You will learn how real gases differ from the ideal gases on which the gas laws are based.
The gas law that includes all four variables—P, V, T, and n—is called the ideal gas law.
The ideal gas constant (R) has the value 8.31 (L·kPa)/(K·mol).—there are other values if you use different units, but it’s easier if you remember on constant and use the same units!
There are attractions between the particles in an ideal gas. Because of these attractions, a gas can condense,or even solidify, when it is compressed or cooled.
Real gases differ most from an ideal gas at low temperatures and high pressures
1. Find the volume of a gas in liters if 2.95 mol has a pressure of 77.0 kPa at a temperature of 52°C.
2. An aerosol spray can with a volume of 325 mL contains 3.00 g of propane (C3H8) as a propellant. What is the pressure in atm of the gas in the can at 28°C?
3. An ideal gas differs from a real gas in that the molecules of an ideal gas
Diffusion is the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout.