5 Steps to a 5 AP Chemistry

S(s) +O 2 (g)→ SO 2 (g)

2 S(s) +3 O 2 (g) →2 SO 3 (g)

If you chose the first equation, the moles of gas produced would be:

(1 mole O 2 ) (1 mole SO 2 /1 mole O 2 ) =1 mole SO 2

If you chose the second equation, the moles of gas produced would be:

(1 mole O 2 ) (2 mole SO 3 /3 mole O 2 ) =2/3 mole SO 2

You get 1 point for either of these solutions. You will also get 1 point if you used

an incorrect number of moles of O 2 from a wrong answer for part b.

e. Either of the possible sulfur oxides will dissolve in water to produce an acid. This will

get you 1 point, as will a similar comment and either of the following equations:

SO 2 +H 2 O → H 2 SO 3

SO 3 +H 2 O → H 2 SO 4

Total your points for the different parts. There are 8 points possible.

 Rapid Review

 Kinetic Molecular Theory—Gases are small particles of negligible volume moving in a

random straight-line motion, colliding with the container walls (that is the gas pressure)

and with each other. During these collisions no energy is lost, but energy may be trans-

ferred from one particle to another; the Kelvin temperature is proportional to the aver-

age kinetic energy. There is assumed to be no attraction between the particles.

 Pressure—Know how a barometer operates and the different units used in atmospheric

pressure.

 Boyle’s law—The volume and pressure of a gas are inversely proportional if the temper-

ature and amount are constant.

 Charles’s law—The volume and temperature of a gas are directly proportional if the

amount and pressure are constant.

 Gay-Lussac’s law—The pressure and temperature of a gas are directly proportional if the

amount and volume are constant.

 Combined gas law—Know how to use the combined gas equation P 1 V 1 /T 1 =P 2 V 2 /T 2.

 Avogadro’s law—The number of moles and volume of a gas are directly proportional if

the pressure and temperature are constant. Remember that 1 mol of an ideal gas at

STP(1 atm & 0°C) occupies a volume of 22.4 L.

 Ideal gas equation—Know how to use the ideal gas equation PV=nRT.

 Dalton’s law—The sum of the partial pressures of the individual gases in a gas mixture

is equal to the total pressure: PTotal=PA+PB+Pc+...

 Graham’s law—The lower the molecular mass of a gas, the faster it will effuse/diffuse.

Know how to use Graham’s law:.

r

r

M

M

1

2

2

1

=

Gases  121