Chapter 12 – The Behavior of Gases Test Topics

Chapter 12 – The Behavior of Gases Test Topics
Chapter 12 Test Thursday, April 28th
Kinetic Molecular Theory
o Principles of the kinetic molecular theory
o Kinetic energy (KE) = ½ mass x velocity2, (KE = ½ mv2) understand how particles of different
masses differ in their velocities if they have the same kinetic energy (if kinetic energies are equal the
particle with the smaller mass must have a higher velocity)
o Relationship between kinetic energy and Kelvin temperature (directly proportional, remember this is
for Kelvin temp, not just temp in general!)
o Factors Affecting Gas Pressure –
 amount of a gas – as amount of gas increases, pressure also increases
 volume – as volume as increases, pressure decreases
 temperature – as temp. increases, pressure also increases
Pressure Conversions - (1 atm = 760 mm Hg = 101.3 kPa = 760 torr = 29.92 in. Hg and 1kPa = 1000 Pa)
Temperature Conversions (K = oC + 273) All temperatures must be in Kelvin before putting them into any
Volume Conversions ( 1 L = 1000 mL)
Grams and moles conversions (you will be given a Periodic Table) – grams to moles (1 mol / molar mass)
and moles to grams (molar mass / 1 mol)
The Gas Laws – you must know the relationship between each variable in these laws. Also, what would a
graph of each of these gas laws looks like and be able to identify by name.
o Boyle’s (P1V1 = P2V2); pressure and volume are inversely proportional when Kelvin temperature and
amount of gas are constant
o Charles’ (V1/T1 = V2/T2); volume and Kelvin temperature are directly proportional when pressure
and amount of gas are constant
o Gay-Lussac’s (P1/T1 = P2/T2 ); pressure and Kelvin temperature are directly proportional when
volume and amount of gas are constant
o Avogadro’s (V1/n1 = V2/n2); volume and number of moles of gas are directly proportional when
pressure and Kelvin temperature are constant
Combined Gas Law (P1V1/T1 = P2V2/T2)
Ideal Gas Law (PV = nRT); P = pressure in atm or kPa, V = volume in Liters, n = number of moles in
moles, and T = Kelvin temperature
o Ideal gas constant values (R = 0.0821 L atm/K mol or 8.314 L kPa/K mol)
Dalton’s Law of Partial Pressures (PTotal = P1 + P2 + …)
o Gases Collected Over Water – you will be given a chart with water vapor pressures; any time a gas
is collected over water, the water vapor pressure must be added to the other gas that is collected to
determine the total pressure of the mixture of gases.
o Including problems with ideal gas law (will have grams or moles) and combined gas laws (no
mention of grams or moles anywhere in the problem)
Graham’s Law of Effusion –
o Diffusion – gas moves from area of higher concentration to area of lower concentration
o Effusion – process of a gas escaping or moving through a small hole in a container
o Equation for diffusion and effusion problems
 (Rate 2/ Rate 1) = √(molar mass 1/molar mass 2)
 Rates must be an amount of gas divided by a period of time (1 mol of gas/25 seconds) not
just an amount of time.
 Rate is inversely proportional to the square root of the molar mass; the higher the molar
mass, the lower the rate of effusion and diffusion
Stoichiometry with gas laws – usually ideal gas law problems