Unit 3 Exam (Fall 2016)
Chem 305 (Nuss)
Seat#________
Name___________________________________
Lab: M Tu W R
TRUE/FALSE. On your Scantron form, mark "A" if the answer is True and "B" if the answer is False. (3.6 pts ea)
1) _____ Liquids with a high viscosity have high intermolecuar forces of attraction.
2) _____ If a hypertonic solution is added to the bloodstream, blood cells will be likely to swell.
3) _____ The smaller the distance between molecules, the smaller the intermolecular forces.
4) _____ In beta emission, the N/P ratio decreases.
5) _____ The best buffers have a weak acid to conjugate base ratio greater than 10:1.
6) _____ The fragmenting of heavy nuclei is referred to as nuclear fission.
7) _____ In wine that is labeled as 18% alcohol, alcohol is the solvent.
8) _____ The conjugate base of H2CO 3 is CO3 29) _____ The stronger the acid, the larger the value of Ka.
10) _____ HSO4 - is an amphiprotic substance.
11) _____ An unsaturated solution will have some solid undissolved in the bottom of the container.
12) _____ Both protons and neutrons are nucleons.
MULTIPLE CHOICE. Choose the alternative that best completes the statement or answers the question. (3.6 pts ea)
13) Which description best fits a gas?
A) Definite shape and volume; strong intermolecular attractions
B) Volume and shape of container; strong intermolecular attractions
C) Volume and shape of container; no intermolecular attractions
D) Definite volume; shape of container; moderate intermolecular attractions
E) Definite volume; shape of container; weak intermolecular attractions
14) Which of the assumptions of the kinetic-molecular theory best explains the observation that a balloon collapses
when exposed to liquid nitrogen (which is much colder than a cold winter day!!)?
A) In collisions with the walls of the container or with other molecules, energy is conserved.
B) The velocity of gas molecules is proportional to their Kelvin temperature.
C) Gas molecules move at random with no attractive forces between them.
D) Collisions with the walls of the container or with other molecules are elastic.
E) The amount of space occupied by a gas is much greater than the space occupied by the actual gas
molecules.
A-1
Name___________________________________
15) Which transformation is condensation?
A) solid → gas
B) liquid → gas
C) liquid → solid
D) gas → liquid
E) solid → liquid
16) The process of sublimation is ________ and involves a(an) ________ in entropy.
A) endothermic; decrease
B) endothermic; increase
C) exothermic; decrease
D) exothermic; increase
E) endothermic; no change
17) Which measurement represents the smallest value of pressure?
A) 785 mm Hg
.
B) 22.0 psi
C) 755 torr
D) 0.750 atm
E) 100 kPa
18) A sample of gas has a volume of 135 mL at 0.600 atm. What would be the volume if the pressure is decreased
to 0.200 atm while temperature is held constant?
A) 135 mL
B) 180 mL
C) 101 mL
D) 45.0 mL
E) 405 mL
19) Which is not an example of a solution?
A) the mixture of gases in a SCUBA diving tank
B) antifreeze in a car radiator
C) spring water purchased at a supermarket
D) hand lotion
E) all of the above are solutions
20) Knowing that solvation involves the creation of solute-solvent interations, the dissolving process is exothermic
when
A) the energy released in solvation exceeds the energy used in breaking up solute-solute and
solvent-solvent interactions.
B) The energy used in solvation exceeds the energy released in breaking up solute-solute and
solvent-solvent interactions.
C) The energy released in solvation is about the same as the energy used in breaking up solute-solute and
solvent-solvent interactions.
D) The energy used in solvation is about the same as the energy released in breaking up solute-solute and
solvent-solvent interactions.
E) The energy used in solvation is less than the energy released in breaking up solute-solute and
solvent-solvent interactions.
A-2
Name___________________________________
21) Which intermolecular forces of attraction are present in CH3 F? (The electronegativities of the elements are
C=2.5, H=2.1, F=4.0)
A) dipole-dipole forces
B) dipole-dipole and London dispersion forces
C) H-bonding and London dispersion foces
D) dipole-dipole, H-boncing, and London dispersion forces
E) None of these statements is correct.
22) In a gas mixture consisting of 35% He and 65% O2 , the total pressure is 800 mm Hg.
What is the partial pressure of O2 ?
A) 65 mm Hg
B) 520 mm Hg
C) 280 mm Hg
D) 35 mm Hg
E) 100 mm Hg
23) Which statement best explains the meaning of the phrase "like dissolves like"?
A) A solvent will easily dissolve a solute of similar mass.
B) The only true solutions are formed when water dissolves a non-polar solute.
C) A solvent and solute with similar intermolecular forces will readily form a solution.
D) The only true solutions are formed when water dissolves a polar solute.
E) None of these statements is correct.
24) Which list includes all the pieces of lab equipment needed to prepare a 0.500 M solution of NaCl from the pure
salt and water?
A) buret; electronic balance
B) electronic balance; volumetric flask
C) buret; volumetric flask
D) volumetric pipet and bulb; volumetric flask
E) electronic balance; graduated cylinder
25) If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy
under the same conditions?
A) 17 L
B) 15 L
C) 8.6 L
D) 12 L
E) 5.0 L
26) The solubility of nitrogen in water when the partial pressure of nitrogen is 593 torr, is 5.3 × 10-4 M. At the same
temperature, what would be the solubility of pure nitrogen, at a pressure of 760 torr?
A) 1500 M
B) 4.1 × 10-4 M
C) 6.8 × 10-4 M
D) 2400 M
E) none of the above
A-3
Name___________________________________
27) What is the % (m/v) concentration of a solution containing 0.250mol of NaF in 500. mL of solution?
A) 1.05%
B) 2.10%
C) 4.20%
D) 5.00%
E) none of these
28) Considering 1.0 M solutions of each substance, which contains the largest concentration of ions?
A) CH4
B) NaOH
C) FeCl3
D) K 2 SO4
E) KCl
29) How many grams are contained in one equivalent of iron (III) ion, Fe3+ ?
A) 0.0537 g
B) 167.6 g
C) 55.85 g
D) 18.62 g
30) Which solution will have the highest boiling point?
A) 0.020 M NH4NO3
B) 0.025 M KNO3
C) 0.020 M CaCl2
D) 0.030 M C6 H12C6
E) 0.018 M Na 3 PO4
31) Which solution is the LEAST concentrated? Each choice refers to the same solute and solvent.
A) 2.4 g solute in 2 mL solution
B) 50 g solute in 175 mL solution
C) 20 g solute in 50 mL solution
D) 2.4 g solute in 5 mL solution
E) 30 g solute in 150 mL solution
32) Which solution is acidic?
A) [H3O+ ] = 1.0 × 10-4 M
B) [OH- ] = 1.0 × 10-7 M
C) [H3O+ ] = 1.0 × 10-10 M
D) [OH- ] = 1.0 × 10-4 M
E) [H3O+ ] = 1.0 × 10-7 M
33) A Bronsted-Lowry base is a substance which
A) accepts protons from other substances.
B) produces hydrogen ions in aqueous solution.
C) accepts hydronium ions from other substances.
D) produces hydroxide ions in aqueous solution.
E) donates protons to other substances.
A-4
E) 6.02 x 1023 g
Name___________________________________
34)
C5H5 N + H2 CO3
C5 H6 N+ + HCO3-
In the reaction shown, the conjugate acid of HCO3 - is ________.
A) H2 CO3
B) H3 O+
C) HCO3 -
D) C5 H6 N+
E) C5 H5N
35) Which substance produces carbon dioxide and water upon reaction with an acid?
A) H2 C2 O4
B) NaCH3 CO2
C) NH4 NO3
D) MgCO3
E) C8 H18
36) Which of the following compounds is a salt?
A) C6 H12O6
B) HBr
D) KNO3
E) H2SO4
D) 0.80 Osmol
E) 0.40 Osmol
C) NaOH
37) What is the osmolarity of a 0.20M solution of K2 SO4 ?
A) 0.20 Osmol
B) 0.60 Osmol
C) 0.10 Osmol
38) Hydrochloric acid is a strong acid in water because it is
A) completely dissociated into hydronium ions and chloride ions.
B) very able to hold onto its hydrogen ion.
C) only slightly dissociated into ions.
D) very soluble soluble.
E) concentrated.
39) If the concentration of OH- in an aqueous solution is 1.4 × 10 -7 M, the concentration of H3 O+ is ________.
A) 7.1 × 10 -8 M
B) 1.3 × 10 -8 M
C) 7.1 × 10 +6 M
D) 1.0 × 10 -7 M
40) Calculate the hydrogen ion concentration in a solution with pH = 6.35.
A) 6.35 M
B) 4.5 × 10-7 M
C) 7.65 M
D) 0.80 M
E) 1.4 × 10 -7 M
E) 2.2 × 10-8 M
41) What is the pH of a solution in which [H3 O+ ] = 3.8 × 10-8 M?
A) 6.58
B) 3.80
C) 2.6 x 10-7
A-5
D) 1.0 x 10-8
E) 7.42
Name___________________________________
42) Which Scientist is credited with the discovery of alpha and gamma radiation?
A) Earnest Rutherford
B) Marie Curie
C) Pierre Curie
D) Henri Becquerel
E) none of the above
43) Which product is formed by alpha emission from polonium-208? The atomic number of polonium is 84.
A)
212
Rn
86
B)
209
Po
84
C)
208
At
85
D)
204
Pb
82
E)
208
Bi
83
44) Which is the best description of a beta particle?
A) charge -1; mass of 0 amu; medium penetrating power
B) charge -1; mass of 0 amu; high penetrating power
C) charge +2; mass of 4 amu; low penetrating power
D) charge +2; mass of 4 amu; high penetrating power
E) charge 0; mass of 0 amu; high penetrating power
45) Which product is formed by beta emission from arsenic-75? The atomic number of arsenic is 33.
A)
75
Ge
32
B)
77
Cu
29
C)
76
As
33
D)
75
Se
34
E)
71
Ga
31
46) Which nuclear reaction is an example of alpha emission?
A)
238
4
Pu + He
94
2
B)
41
0
Ar +
e
18
-1
C)
242
Cm
96
D)
22
Na
11
E)
63
Ni
28
→
→
→
→
→
242
Cm
96
41
Cl
17
238
4
Pu + He
94
2
22
0
Ne +
β
10
+1
63
0
Cu +
β
29
-1
47) Which of the following is not an example of ionizing radiation?
A) alpha particles
B) ultraviolet rays
C) gamma rays
D) X-rays
E) beta particles
48) The half-life of sodium-24 is 15.0 hours. What percentage of a sample of sodium-24 remains after 60.0 hours?
A) 0.00%
B) 6.25%
C) 25.0%
D) 3.13%
E) 12.5%
A-6
Name___________________________________
81
49) Determine the identity of the daughter nuclide from the electron capture by
Rb.
37
A)
81
Sr
38
B)
80
Kr
36
C)
85
Y
39
D)
77
Br
35
E)
81
Kr
36
1
n
0
D)
2
H
1
E)
4
He
2
E)
11
B
5
50) What is the missing reactant in the reaction shown?
35
Cl + ________
17
A)
1
H
1
32
4
P + He
16
2
→
B)
0
e
-1
C)
51) Which nuclear reaction is an example of fusion emission?
A)
238
4
Pu + He
94
2
B)
63
Ni
28
C)
41
0
e
Ar +
18
-1
D)
22
Na
11
E)
7
1
Li + H
3
1
→
→
→
242
Cm
96
63
0
Cu +
β
29
-1
→
41
Cl
17
22
0
Ne +
β
10
+1
→
1
7
n + Be
0
4
52) Determine the identity of the daughter nuclide from the positron emission of
A)
12
N
7
B)
12
C
6
C)
10
B
5
53) Which reaction is an example of the start of a chain reaction?
51
51
0
A)
Ti →
V +
e
22
23
-1
B)
242
Cm
96
→
C)
46
Sc
21
46
Sc + energy
21
D)
242
4
Cm + He
96
2
→
E)
235
1
U + n
92
0
138
95
1
Te +
Zr + 3 n
52
40
0
→
238
4
Pu + He
94
2
→
245
1
Cf + n
98
0
A-7
D)
11
C.
6
11
N
7
Name___________________________________
54) What is the molarity of a solution prepared by dissolving 0.750 grams CaCl2 in enough water to make 500. mL
of solution?
A) 0.0135M
B) 1.50M
C) 0.667M
D) 1.35M
55) A sample of helium has a volume of 485 mL at 37.0°C and 720 mm Hg. The temperature is lowered to 22.0°C
and the pressure to 625 mm Hg. What is the new volume?
A) 587 mL
B) 883 mL
C) 532 mL
D) 332 mL
E) 940 mL
56) Calculate the pH of a buffer that is 0.158 M HClO and 0.099 M NaClO. The Ka for HClO is 2.9 × 10 -8 .
A) 7.34
B) 7.54
C) 7.74
D) 6.46
E) 6.26
A-8
Name___________________________________
57) How many mL of 0.150 M NaOH are needed toreach the end point in the titration of 50.00 mL of a 0.120 M
solution of H2 SO4 ?
A) 40.0 mL
B) 60.0 mL
C) 80.0 mL
D) 100 mL
E) 160 mL
58) How many grams of O2 are contained in a 25.0 L sample at 3.95x103 mmHg and 28.0°C?
A) 3998g
B) 70.9g
C) 763g
A-9
D) 56.5g
E) 168g
Name___________________________________
59) How many kJ of heat are required to warm 25g of water from 42°C to its boiling point of 100°C and to convert it
to steam. The specific heat of water is 1.00 cal/g °C and the heat of vaporaization is
540. cal/g
A) 125kJ
B) 15kJ
C) 783kJ
D) 808kJ
E) 570kJ
60) By how much does the pH change if 0.010 mole of HCl is added to 0.280L of a buffer that is 0.100M in HCN
and 0.100M in NaCN? The Ka of HCN is 4.9x10-10.
A) -1.4 pH units
B) -0.54 pH units
C) -0.12 pH units
D) -0.32 pH units
E) none of these answers are correct
A-10