CHY 115 General Chemistry I

Chapter 5: Gases

Suggested end of chapter problems: 23, 25-29 (see page 190 for information on the pressure unit Pascals),31-39, 41 -45, 47, 49-52, 54, 59 (I expect questions), 61, 62, 65, 69, 81, 82, 84

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Section 5.1 Pressure

1. Describe how a barometer measures air pressure. Explain why Hg is used in barometers and not water.
2. Know the following are pressure units: mm Hg, torr, atm, Pascals, psi
3. Know that mm Hg = torr.
4. Know that 1 atm = 760 mm Hg. You will be given equivalence statements for the other pressure units.
5. Convert between pressure units.
6. Describe how a manometer is used to measure pressure on a gas.

1. State Boyle's, Charles', and Avogadro's laws -- in words and mathematically.
2. Explain the meaning of directly and inversely related.
3. Analyze data to determine if/when the gas is behaving as an ideal gas. (see 195 for an example) Note - a gas is most likely to obey the gas laws at high temperature and low pressure (less than 1 atm). At higher pressures and lower temperatures gases deviate slightly from the gas laws.
4. Apply the gas laws mathematically.

1. Know the ideal gas law. You will be given R.
2. Know what R represents.
3. Apply the ideal gas law mathematically.

1. State STP conditions. 
2. Calculate the volume of 1.00 moles of a gas at STP.
3. Calculate the density of any gas at STP conditions (in g/L).
4. Calculate the density of any gas under a given set of conditions.
5. Solve problems such as those in the sample exercises for this section.

1. State Dalton's law in words and mathematically.
2. Calculate the partial pressure of the gases in a mixture of gases given either their individual pressures or the total pressure and the number of moles of each gas present.
3. Define and calculate mole fractions.
4. Explain why barometric pressure must be corrected for the vapor pressure of water when a gas is collected over water.
5. State how vapor pressure and temperature are related (directly or inversely?).
6. Solve problems similar to the gas law experiment we did in lab. You will not have to correct the pressure for a water column.

1. Read pages 212-215. KMT should make sense to you. Do not worry about 216-218.
2. You should be able to explain, based on KMT, either Boyle's, Charles', Avogadro's, or Dalton's Law.

1. Define diffusion and effusion as they relate to gases. (How are they different?)
2. State Graham's law mathematically and in words.
3. Apply Graham's law mathematically.
4. Explain why Graham's law cannot be applied to the diffusion of gases in air (See last paragraph of section 5.7 on page 222).