Download 1. Is H3O polar or non-polar? (1 point) a) Polar b

CHEMISTRY 101
EXAM 3 (FORM B)
DR. SIMON NORTH
1. Is H3O+ polar or non-polar? (1 point)
a) Polar
b) Non-polar
2. The bond strength is considerably greater in HF than in the other three hydrogen
halides (HCl, HBr, and HI). (1 point)
a) True
b) False
3. Water can be classified as (3 points)
a)
b)
c)
d)
e)
A strong acid and a weak base
A weak acid and a strong base
A weak acid and a weak base
Only an acid
Neither an acid nor a base
4. When considering conjugate acids and bases, (2 points)
a)
b)
c)
d)
e)
Strong bases have strong conjugate acids.
Strong acids have strong conjugate bases.
Strong bases have weak conjugate acids.
Weak acids have weak conjugate bases.
None of the above is true.
5. What is the hybridization of the central atom in BF3? (3 points)
a)
b)
c)
d)
e)
sp
sp2
sp3
sp3d
sp3d2
6. How many of the following statements are false? (5 points)
- Strong acids dissociate completely in water
- Arrhenius acids and bases necessarily make water and a salt when combined.
- Acidic aqueous solutions do not conduct electricity.
- Acid strengths of most ternary acids containing the same central element
decrease with decreasing oxidation state of the central element (i.e. with
decreasing number of oxygen atoms).
- Lewis acids and bases necessarily make water and salt when combined.
a)
b)
c)
d)
e)
1
2
3
4
5
7. In the laboratory a student combines 500.0 mL of a 1.0 M H3PO4
with 500.0 mL of a 1.0 M Ca(OH)2. (5 points)
2H3PO4 + 3Ca(OH)2 Ca3(PO4)2 + 6H2O
What is the final concentration of calcium phosphate?
a)
b)
c)
d)
e)
0.17 M
0.25 M
0.50 M
2.0 M
1.0 M
8. What are the approximate angles in ICl2-? (3 points)
a)
b)
c)
d)
e)
90°
120°
109°
30°
180°
9. According to Lewis Theory, an acid is any species that donates an electron
pair. (1 point)
a) True
b) False
10. A molecule with 2 double bonds and 5 single bonds has 7 sigma bonds.
(1 point)
a) True
b) False
11. 85.0 mL of 0.0650 N H2SO4 solution required 50.5 mL of NaOH solution for
neutralization. Calculate the normality and the molarity of the sodium hydroxide
solution. (5 points)
a)
b)
c)
d)
e)
0.11 M and 0.055 N
0.22 M and 0.22 N
0.11 M and 0.11 N
0.11 M and 0.055 N
0.44 M and 0.44 N
12. Given the following reaction,
2Na + H2O Na2O + H2
which of the following statements is true? (5 points)
a)
b)
c)
d)
e)
Water is the oxidizing agent and Na is the reducing agent
Na is the oxidizing agent and water is the reducing agent
Water is being oxidized and Na is being reduced
b) and c) are correct
This is not a redox reaction
13. The polarity of covalent bonds derives from electronegativity differences.
(1 point)
a) True
b) False
14. In the following reaction, the oxidation state of Al changes from (3 points)
3KClO4 + 8Al 3KCl + 4Al2O3
a)
b)
c)
d)
e)
+3 to +1
+3 to -2
0 to +3
+3 to 0
0 to +6
15. The following skeletal oxidation-reduction reaction occurs under acidic conditions.
Write the balanced oxidation half-reaction. (5 points)
Pb2+ + Fe3+ PbO2 + Fe2+
a)
b)
c)
d)
e)
Fe3+ Fe2+ + ePb2+ + 2H2O PbO2 + 4H+ + 2eFe3+ + e- Fe2+
Pb2+ + O2 + 2e- PbO2
None of the above
16. You wish to make a 0.264 M HClO4 solution from a stock solution
of 12.0 M HClO4. How much concentrated acid must you add to obtain a total
volume of 300 mL of the dilute solution ? (5 points)
a)
b)
c)
d)
e)
330.0 mL
6.60 mL
0.04 mL
0.02 mL
3.30 mL
17. What orbitals make up the pi bond between C and C in H2C=CH2?
(5 points)
a)
b)
c)
d)
e)
sp2 on each C
sp3 on each C
2s on each C
2p on each C
none of the above
18. Pi bonds can be formed between p orbitals. (1 point)
a) True
b) False
19. Is trans-dichloro-ethene (CH2Cl2) polar or non-polar? (2 points)
a) Polar
b) Non-polar
20. The following unbalanced reaction takes place in acidic conditions.
Cr2O72- + Fe2+ Cr3+ + Fe3+
How many moles of electrons are transferred per mole of dichromate reacted?
(5 points)
a)
b)
c)
d)
e)
5
6
7
8
9
21. The conjugate acid of NH3 is
a)
b)
c)
d)
e)
NH3+
NH2NH3OH
NH4+
Not given
(2 points)
22. What is the normality of a solution prepared by dissolving 4.3 g of HClO4 in 286 mL
of water? (3 points)
a)
b)
c)
d)
e)
0.60 N
0.30 N
0.15 N
0.0003 N
0.0006 N
23. What is the electronic geometry about the I in IBr2+? (3 points)
a)
b)
c)
d)
e)
linear
trigonal planar
tetrahedral
trigonal bipyrimidal
bent
24. What is the molecular geometry of the above molecule? (3 points)
a)
b)
c)
d)
e)
linear
trigonal planar
tetrahedral
trigonal bipyrimidal
bent
25. Given the following equation, (2 points)
F- + BF3 BF4Which of the following statements is true?
a)
b)
c)
d)
e)
BF3 is an Arrhenius acid and F- is an Arrhenius base
BF3 is a lewis base and F- is a lewis acid
This is not an acid base reaction
BF3 is a lewis acid and F- is a lewis base
Only Bronsted-Lowry theory can describe this reaction as an acid-base reaction
26. In the following reaction, (2 points)
NH3 + H2O NH4+ + FWhich is the Bronstead-Lowry base?
a) H2O
b) NH3
c) neither
27. Given the following list of acids, which is/are strong? (5 points)
1)
2)
3)
4)
5)
a)
b)
c)
d)
e)
HBr
HClO4
HClO3
HNO3
HI
None are strong
1,2,4
1,2,5
1,2,3,4
All are strong
28. Calculate the normality of a solution that contains 156 g of calcium hydroxide,
Ca(OH)2 in 1500 mL of solution. (3 points)
a)
b)
c)
d)
e)
2.8 N
5.6 N
1.4 N
0.0056 N
0.0028 N
29. H2CO3 is a (2 point)
a) strong acid
b) weak acid
c) strong base
d) weak base
e) soluble salt
30. When the following unbalanced reaction is balanced under acidic conditions,
MnO4-(aq) + C2O42-(aq) Mn2+(aq) + CO2(g)
what is the stoichiometric coefficient in front of the MnO4-? (5 points)
a)
b)
c)
d)
e)
1
2
3
4
5
31. The oxidation state of the carbon in the above question changes from (3 points)
a)
b)
c)
d)
e)
+3 to +4
+3 to 0
+4 to 0
no change in oxidation state
none of the above
32. Given that Zn(OH)2 is amphoteric, which of the following statements is false?
(5 points)
a)
b)
c)
d)
e)
Zn(OH)2 acts as an acid in the presence of strong base
Zn(OH)2 can react with an electron donor.
Zn(OH)2 must be able to donate a proton.
Zn(OH)2 acts as a base in the presence of strong acid
None of these statements are false