Unit 7: Gas Laws

You will be able to:

1. list the characteristics of an ideal gas according to the kinetic theory of gases.
   explain the difference between absolute and gauge pressure.

2. list observed properties of a gas. (indefinite shape, can be compressed, can expand, have low densities, diffuse uniformly through their containers to form homogenous mixtures)
   describe the function and calculate the pressure of a barometer and closed-tube manometers.

3. identify the variables that affect the pressure of a gas.
   state whether gas pressure increases or decreases for a given change in the volume, temperature, or the number of moles of a gas.
   sketch a graph of the pressure-volume, volume-temperature, and pressure-temperature relationship for a gas.
   calculate the pressure/volume, volume/pressure, and pressure/temperature of a gas after a change in the other.

4. calculate the pressure, volume, temperature, or moles of gas from the ideal gas equation.
   calculate the molar mass of a gas from the ideal gas equation.
   calculate the pressure, volume, or temperature for a gas after a change in the other two.
   calculate the number of moles of gas given pressure, volume, and temperature.
   solve stoichiometry problems involving gas volumes.
   determine the value of absolute zero from a graph of volume or pressure vs. temperature.

5. Explain the reasons for deviation from ideal behavior as seen in the van der Waals equation.
   explain why some gasses deviate more from ideal behavior than others.

6. apply Dalton’s law of partial pressures to a mixture of gases and to the collection of gas over water.
   explain the concept of vapor pressure.
   state the relationship between vapor pressure and temperature.
   
   

Reading:

1. 13.1  Kinetic Molecular Theory
   13.2  Gas Pressure
   13.3  Atmospheric Pressure
   13.4  Pressure Units and Conversions
   13.5  Average Kinetic Energy and Temperature

2. 14.1  Compressibility
   14.2  Factors Affecting Gas Pressure

3. 14.3  Boyle's Law
   14.4  Charles's Law
   14.5  Gay-Lussac's Law
   14.6  Combined Gas Law
   14.7  Avogadro's Law

4. 14.8  Ideal Gas Law
   14.9  Calculating the Molar Mass of a Gas
   14.10  Gas Stoichiometry

5. 14.11  Real and Ideal Gases

6. 14.12  Dalton's Law of Partial Pressures

14.13  Mole Fraction

14.14  Gas Collection by Water Displacement

Sildes

Laboratory

Boyle's Law Experiment (Bicycle bump, soda bottle, syringe)

-Purpose (explore the relationship between pressure and volume)

-Data

-Graph

-Analysis  (Are pressure and volume directly or inversely proportioanl?

Soda Can

• Find the volume of the can and record the result to the correct number of significant digits.  Describe your method for finding the volume.

• Explain why the volume of liquid in the can is less than the total volume of the can.

• Add 50.0 mL of water to the can.  Place the can on the hotplate (setting: 50%).  Record the temperature inside the can periodically.  Make and record other observations.

• Prepare an ice bath and record the temperature.

• When the temperature of the contents of the can stabilizes at a maximum value, record the value.  Quickly invert the can into your ice bath and then promptly remove the can from the ice bath.  Find the volume of the water in the can and the volume of the can.  Record your observations.  Provide an explanation for your observations. 

Collecting a gas over water (Magnesium Ribbon Lab)

• Perform the calculations needed to decide how much magnesium ribbon to use in order to collect 40 mL of hydrogen gas.

Worksheets

Additional Resources