1
W(g) + X(g)  Y(g) + Z(g)
Gas W and X react in a closed, rigid vessel to form Gas Y
and Z according to the equation above. The initial
pressure of W(g) is 1.20 atm and that of X(g) is 1.60 atm.
No Y(g) or Z(g) is initially present. The experiment is
carried out at constant temperature. What is the partial
pressure of Z(g) when the partial pressure of W(g) has
decreased to 1.0 atm?
3
A rigid metal tank contains oxygen gas. Which of the
following applies to the gas in the tank when additional
oxygen is added at constant temperature?
(A) The volume of the gas increase.
(B) The pressure
of the gas decreases.
(C) The average speed of the gas molecules remains the
same.
(D) The total number of gas molecules remains the same.
(E) The average distance between the gas molecules
increases.
5
If the absolute temperature of a gas is doubled and the
pressure of the gas is halved, how will the volume
change?
(a)It will increase by two times its original value.
(b)It will decrease to one fourth of its original value.
(c)It will stay the same as its original value.
(d)It will increase by four times its original value.
7
The density of an unknown gas is 4.20 grams per liter at
3.00 atmospheres pressure and 127 °C. What is the
molecular weight of this gas?
2
10 HI + 2 KMnO4 + 3 H2SO4  5 I2 + 2 MnSO4 + K2SO4
+ 8 H2O
According to the balanced equation above, how many
moles of HI would be necessary to produce 2.5 mol of I2,
starting with 4.0 mol of KMnO4 and 3.0 mol of H2SO4?
4
How many PopTarts� are needed to convert 1,000.0 g of
water at 20.0 oC to steam at 100.0 oC? One PopTart is
equal to 800,000 J of energy...wow!
6
A sample of 9.00 grams of aluminum metal is added to an
excess of hydrochloric acid. The volume of hydrogen gas
produced at standard temperature and pressure is…
8
What is the molarity of 175 mL of solution containing
2.18 grams of Na2SO4•10H2O?
9
The solubility of a gas will _?_ when a solution
containing the gas is heated and the solubility of a gas in
a solution will _?_ when the pressure over the solution is
decreased.
11
2 H2O(l) + 4 MnO4−(aq) + 3 ClO2−(aq)  4 MnO2(s)
+ 3 ClO4−(aq) + 4 OH−(aq)
According to the balanced equation above, how many
moles of ClO2−(aq) are needed to react completely with
20. mL of 0.20 M KMnO4 solution?
13
The simplest formula for an oxide of nitrogen that is 36.8
percent nitrogen by weight is…
(A) N2O
(B) NO
(C) NO2
(D) N2O3
(E)
N2O5
15
2 K + 2 H2O  2 K+ + 2 OH− + H2
When 0.400 moles of potassium reacts with excess water
at standard temperature and pressure as shown in the
equation above, the volume of hydrogen gas produced is
10
What is the total pressure, in atmospheres, of a 10.0
L container that contains 10 moles of nitrogen gas
and 10 moles of oxygen gas at 300 K?
12
A compound is heated to produce a gas whose molecular
weight is to be determined. The gas is collected by
displacing water in a water-filled flask inverted in a
trough of water. Which of the following is necessary to
calculate the molecular weight of the gas, but does NOT
need to be measured during the experiment?
(A) Mass of the compound used in the experiment
(B) Temperature of the water in the trough
(C) Vapor pressure of the water (D) Barometric pressure
(E) Volume of water displaced from the flask
14
Which has an average atomic or molecular speed closest
to that of N2 molecules at 0°C and 1 atm?
Which has the greatest density?
Which has the greatest rate of effusion through a pinhole?
(A) Ne
(B) Xe
(C) O2
(D) CO
(E) NO
16
If 88.0 grams of solid carbon dioxide evaporates,
how many liters of CO2 gas will be formed at a
temperature of 300 K and 2.00 atmospheres of
pressure?
17
How many grams of NaOH are needed to make 100
milliliters of a 0.2 molar solution of NaOH?
19
A 27.0-gram sample of an unknown hydrocarbon was
burned in excess oxygen to form 88.0 grams of carbon
dioxide and 27.0 grams of water. What is a possible
molecular formula of the hydrocarbon?
(A) CH4
(B) C2H2
(C) C4H3
(D) C4H6
(E) C4H10
18
As the temperature is raised from 100 °C to 200 °C, the average
kinetic energy of neon atoms changes by a factor of…
20
If an air bag in a car needs 44.8 L of gas when filled, how
many grams of NaN3 are needed to fill the bag with
nitrogen gas at standard temperature and pressure?
Remember that one mole of any gas will occupy 22.4 L at
STP. The balanced chemical is...
22
21
Calculate the molarity of the resulting solution if 25.0 mL
of 2.40 M HCl solution is
diluted to 300. mL.
23
How many milliliters of 2 M NaCl solution are required
to make 1 liter of 0.4 M NaCl solution?
A hot-air balloon rises. Which of the following
is the best explanation for this observation?
(A) The pressure on the walls of the balloon increases with
increasing temperature.
(B) The difference in temperature between the air inside and
outside
the balloon produces convection currents.
(C) The cooler air outside the balloon pushes in on the walls of
the balloon.
(D) The rate of diffusion of cooler air is less than that of
warmer air.
(E) The air density inside the balloon is less than that of the
surrounding air.
24
A sample of an ideal gas is cooled from 50.0 °C to 25.0
°C in a sealed container of constant volume. Which of the
following value(s) for the gas will decrease?
I. The average molecular mass of the gas
II. The average distance between the molecules
III. The average speed of the molecules
26
25
What mass of Na2SO4 is required to prepare 400. mL of
1.50 M Na2SO4 solution?
After completing an experiment to determine gravimetrically
the percentage of water in a hydrate, a student reported a value
of 38 percent. The correct value for the percentage of water in
the hydrate is 51 percent. Which of the following is the most
likely explanation for this difference?
A) Strong initial heating caused some of the hydrate sample to
spatter out of the crucible.
B) The dehydrated sample absorbed moisture after heating.
C) The amount of the hydrate sample used was too small.
D) The crucible was not heated to constant mass before use.
E) Excess heating caused the dehydrated sample to decompose.
28
27
A sample of 10.6 g of KNO3 was dissolved in 251.0 g of
water at 25 oC in a calorimeter. The final temperature of
the solution was 21.5 oC. What is the molar heat of
solution of KNO3? Assume the c of the solution is 4.184
J/gdeg and that the calorimeter does not gain or lose heat.
Equal masses of three different ideal gases, X, Y, and Z, are
mixed in a sealed rigid container. If the temperature of the
system remains constant, which of the following statements
about the partial pressure of gas X is correct?
(A) It is equal to 1/3 the total pressure
(B) It depends on the intermolecular forces of attraction
between molecules of X, Y, and Z.
(C) It depends on the relative molecular masses of X, Y, and Z.
(D) It depends on the average distance traveled between
molecular collisions.
(E) It can be calculated with knowledge only of the volume of
the container.