Chemistry 121 Practice exam #3
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
How many molecules of water, O, are present in 75.0 g of O?
1)
______
A)
75.0 molecules
B)
4.17 molecules
C)
5.02 × molecules
D)
2.51 × molecules
E)
7.53 × molecules
2)
Given the following equation, what is the correct form of the conversion factor needed to convert the number of moles of to the number of moles of produced?
4Fe(s) + 3 (g) → 2(s)
2)
______
A)
B)
C)
D)
E)
For the question(s) that follow, consider the following equation.
2Mg + → 2MgO
3)
The number of moles of oxygen gas needed to react with 4.0 moles of Mg is
3)
______
A)
1.0 mole.
B)
2.0 moles.
C)
3.0 moles.
D)
4.0 moles.
E)
6.0 moles.
4)
The force of gas particles against the walls of a container is called
4)
______
A)
temperature.
B)
pressure.
C)
volume.
D)
density.
E)
quantity of gas.
5)
A 5.00-L tank contains helium gas at 1.50 atm. What is the pressure of the gas in mmHg?
5)
______
A)
507 mmHg
B)
1.50 mmHg
C)
1140 mmHg
D)
760 mmHg
E)
7.5 mmHg
6)
When 4 moles of aluminum are allowed to react with an excess of chlorine gas, , how many moles of aluminum chloride are produced?
6)
______
A)
4 moles
B)
1 mole
C)
2 moles
D)
3 moles
E)
5 moles
7)
The volume of a gas with a pressure of 1.2 atm increases from 1.0 L to 4.0 L. What is the final pressure of the gas, assuming constant temperature?
7)
______
A)
0.30 atm
B)
4.8 atm
C)
1.2 atm
D)
1.0 atm
E)
3.3 atm
8)
Complete the following statement: In Charles's Law, the volume of a gas ______when the ______decreases.
8)
______
A)
increases; pressure
B)
decreases; temperature
C)
increases; quantity of gas
D)
increases; temperature
E)
decreases; pressure
9)
A gas at 5.00 atm pressure was stored in a tank during the winter at 5.0 °C. During the summer, the temperature in the storage area reached 40.0 °C. What was the pressure in the gas tank then?
9)
______
A)
40.0 atm
B)
0.625 atm
C)
69.5 atm
D)
4.44 atm
E)
5.63 atm
10)
When the combined gas law is rearranged to solve for , the following is the
10)
______
A)
/
B)
/-/
C)
/
D)
/
E)
/
11)
At STP, temperature and pressure have the values of
11)
______
A)
273 K and 1 mmHg.
B)
273 K and 760 mmHg.
C)
0 K and 1 atm.
D)
0 K and 760 mmHg.
E)
760 K and 273 atm.
12)
The O-H bond in water is polar because
12)
______
A)
hydrogen is much more electronegative than oxygen.
B)
it is an ionic bond.
C)
oxygen is much more electronegative than hydrogen.
D)
oxygen occupies more space than hydrogen.
E)
it is a hydrogen bond.
13)
A solution is prepared by dissolving 2 g of KCl in 100 g of O. In this solution, O is the
13)
______
A)
ionic compound.
B)
solution.
C)
solid.
D)
solvent.
E)
solute.
14)
In a solution, the solvent
14)
______
A)
is the substance present in the smallest concentration.
B)
can be a liquid or gas.
C)
can be a solid, liquid, or gas.
D)
is never a solid.
E)
is a liquid.
15)
Oil does not dissolve in water because
15)
______
A)
water is nonpolar.
B)
oil is hydrated.
C)
oil is nonpolar.
D)
oil is polar.
E)
water is saturated.
16)
When KCl dissolves in water
16)
______
A)
the ions are attracted to the partially negative oxygen atoms of the water molecule.
B)
the ions are attracted to the partially positive hydrogen atoms of the water molecule.
C)
the ions are attracted to dissolved ions.
D)
the ions are attracted to the partially negative oxygen atoms of the water molecule.
E)
the ions are attracted to ions on the KCl crystal.
17)
In water, a substance that ionizes completely in solution is called a
17)
______
A)
weak electrolyte.
B)
nonconductor.
C)
semiconductor.
D)
strong electrolyte.
E)
nonelectrolyte.
18)
In water, a substance that partially ionizes in solution is called a
18)
______
A)
nonelectrolyte.
B)
semiconductor.
C)
strong electrolyte.
D)
nonconductor.
E)
weak electrolyte.
19)
An increase in the temperature of a solution usually
19)
______
A)
increases the solubility of a solid solute in the solution.
B)
decreases the solubility of a solid solute in the solution.
C)
increases the solubility of a gas in the solution.
D)
increases the boiling point.
E)
decreases the solubility of a liquid solute in the solution.
20)
Which one of the following compounds will be soluble in water?
20)
______
A)
B)
LiCl
C)
D)
E)
AgCl
21)
When solutions of KCl and are mixed, a precipitate forms. Which of the following is the balanced equation for the double replacement reaction that occurs?
21)
______
A)
KCl(aq) +(aq) → (aq) +(s)
B)
2KCl (aq) +(aq) → 2 (aq) + (s)
C)
(aq) + NO3-(aq) → (aq)
D)
(aq) +(s) → KCl(aq) +(aq)
E)
KCl(aq) +(aq) → (aq) + PbCl(s)
22)
Which one of the following compounds will NOT be soluble in water?
22)
______
A)
PbS
B)
C)
NaOH
D)
E)
23)
According to Henry's law, the solubility of a gas in a liquid
23)
______
A)
increases as the gas pressure above the liquid increases.
B)
depends on the liquid density.
C)
depends on the liquid polarity.
D)
remains the same as the temperature increases.
E)
decreases as the gas pressure above the liquid increases.
24)
What is the molarity of a solution that contains 17 g of in 0.50 L of solution?
24)
______
A)
34 M
B)
0.50 M
C)
1.0 M
D)
2.0 M
E)
0.029 M
25)
The molarity (M) of a solution refers to
25)
______
A)
grams of solute/100 mL of solution.
B)
moles of solute/L of solution.
C)
grams of solute/L of solution.
D)
moles of solute/L of solvent.
E)
moles of solute/100 mL of solution.
26)
How many moles of are in 250 mL of a 3.0 M of solution?
26)
______
A)
0.75 mole
B)
3.0 moles
C)
1.3 moles
D)
750 moles
E)
83 moles
27)
Duringtheprocessofdilutingasolutiontoalowerconcentration,
27)
______
A)
theamountofsolutedoesnotchange.
B)
waterisremovedfromtheconcentratedsolution.
C)
thevolumeofthesolutiondoesnotchange.
D)
theamountofsolventdoesnotchange.
E)
thereismoresoluteintheconcentratedsolution.
28)
WhatisthemolarityofaKClsolutionmadebydiluting75.0mLofa0.200Msolutiontoafinalvolumeof100.mL?
28)
______
A)
0.150M
B)
0.100M
C)
6.67M
D)
0.200M
E)
0.267M
1)
D
2)
E
3)
B
4)
B
5)
C
6)
A
7)
A
8)
B
9)
E
10)
A
11)
B
12)
C
13)
D
14)
C
15)
C
16)
A
17)
D
18)
E
19)
A
20)
B
21)
B
22)
A
23)
A
24)
D
25)
B
26)
A
27)
A
28)
A
Part 2: Short Answer: