REVIEW FOR 1st Semester EXAM
AP Chem
1-1. How many protons neutrons and electrons are in
56
Co3+?
2-1. A sample of a compounds found to contain 2.38 g nitrogen and 1.36 g oxygen.
What is the simplest formula?
2-2. A 0.2000 g sample of vitamin C which contains only C, H, and O, is reacted
completely with oxygen to give 0.2999 g CO2 and 0.08181 g H2O. What is the
empirical formula of vitamin C?
3-1. How many moles of F2 are required to combine with 3.11 mol Xe to produce
XeF4?
3-2. How many grams of oxygen are needed to react with 21.4 g chromium in order
to produce the paint pigment chromium oxide, Cr2O3?
4-1. A mixture of 54 g aluminum and 32 g oxygen were reacted to completion
according to
4 Al + 3 O2 → 2 Al2O3.
Which reagent was in excess and by how much?
4-2. The reaction of 25.0g benzene, C6H6, with excessHNO3 resulted in 21.4 g
C6H5NO2. What is the percent yield? The equation is:
C6H6+ HNO3
C6H5NO2 +H2O
5-1. A gas at 25oC and 680torr occupies 345 mL. How many moles are present?
5-2. A sample of gas occupies 30.0L at 0.800 atm and 298 K. How many moles of
gas are in the sample?
5-3. How many liters of chlorine gas can be produced by the electrolysis reaction
of 6 mol NaCl at 27oCand 1 atm?
2 NaCl(s)
2 Na(s) + Cl2(g)
6-1. A 205 mL sample of gas at 100oC and 755 torr is found to have a mass of 1.22
g. What is the molar mass of the gas?
6-2. What mass of gas X (MM=26.5 g/mol)occupies 9.84 L at a pressure of 172
torr and 27oC?
7-1. A gas has a density of 2.86 g/L at STP. Which of the following could it be?
O2
SO2
CO2
AsH3
7-2. Determine the density of H2S gas at 27oC and 2.00 atmospheres pressure.
8-1
Balance the following redox reaction that occurs in acid.
MnO4- + Fe2+  Mn2+ + Fe3+
8-1
Balance the following redox reaction that occurs in basic solution.
NO2- + Al  NH3 + AlO2-
9-1. A gas at 750 torr and with a volume of 2.00 L is allowed to change its volume
at constant temperature until the pressure is 600 torr. What is the new volume of
the gas?
9-2. A sample of gas in a size-adjustable container occupies 500 L. If the
pressure is quadrupled and the temperature is reduced to 1/3 its original value,
what is the new volume?
10-1. The rate of effusion of gas X is found to be about 1.3 times that of
SF6(g). What is the molecular weight of X?
11-1 Calculate the wavelength of light emitted when an electron changes from n =4
to n =2 in the hydrogen atom. What type of electromagnetic radiation is emitted?
13-1. Classify each of the following atom (or ion)/electronic configuration
combinations as ground state, excited state, or not allowed
a. Ga [Ar] 4s2 3d12
b. Ni [Ar] 4s2 3d8
c. S2- [Ne] 3s23p6
d. N 1s2 2s12p4
13-2. Which of the following has one or more unpaired electron(s) in the ground
state?
Be
K+ Cd
Se
S2-
13-3. Give the complete electronic configuration for calcium.
13-4. What atom has this electronic configuration: [Ar] 4s2 3d10 4p3?
14-1. Select the largest species of each of these groups:
a. Ti2+ Ti3+Ti
b. F- Ne Na+
14-2. Which has the largest first ionization energy for each of these groups:
a. Na K Rb
b. F Ne Na
14-3. Which has the lowest first ionization energy for the group?
K Ca Se Br Kr
14-4. Which set is listed in order of increasing effective nuclear charge?
a. O, C, N
b. B, C, O
c. F, Cl, Br
d. F, S, As
15-1. How many electrons should be in the Lewis structure of the phosphate ion,
PO4-3?
15-2. Which of the following has lone pairs of electrons on the central atom?
ICl3 NF3 CO2 CCl4
15-3. In which of the following is the actual structure a resonance hybrid of Lewis
structures?
O=C=O H-O-H O=S-O CCl4
15-4. Which of the following molecules do not obey the octet rule?
a. NF3 b. SF4 c. PF4+ d.BF3
15-5. How many resonance forms are possible for each of these without expanding
the octet?
a. CO3-2 b. NO21 c. SO42-
15-6. Which compound has only one lone pair on the central atom?
SF2 SiF4 NF3 XeO4 PF4+
16-1. Draw the Lewis dot structure for each of the following compounds.
Determine it the compound is polar.
a. NF3 b. SF2 c. SiF4 d. CS2
17-1. What are the names of the molecular shapes associated with the symbolic
formula AB3and AB3E?
17-2. What is the shape of the following molecules?
ClF3 PH3 TeCl2 CO2 SiF4
18-5. Which of the following molecules is polar?
CH4 BF3 XeO4 SO2
19-1. What is the hybridization predicted for the nitrogen in NF3? How many
sigma bonds are present? How many pi bonds are present?
20-1. In the thermite reaction:2 Al + Fe2O3
Al2O3 + 2 Fe H= -849 kJ, how
much heat is produced at the same time 100.0 g Fe is produced?
20-2. Calculate the mass of mercury which can be liberated from HgO at 25oC by
the treatment of excess HgO with 41.84 kJ heat. HgO(s)
Hg + 1/2 O2(g) H=
+90.8 kJ
22-1. Given these two reactions:
X(s) + O2(g)
XO2(g) Ho= -297 kJ.mol
2 X(s) + 3 O2(g)
2 XO3(g) Ho= -792 kJ.mol
Calculate Ho for the reaction
XO2(s)+ 1/2 O2(g)
XO3(g)Ho= ?
23-1. Using heat of formation data calculate Ho for the following reaction.
Na2CO3(s)+ 2 HCl(g)
H2O(l)+ CO2(g) + 2 NaCl(s)
Answers:
1-1 27 p + 29 n + 24 e
2-1
N2O
3-1
6.2 mol F2
2-2
C3H4O3
3-2
9.88 g
4-1
Al, 18 g excess
4-2
54.3 %
5-1
0.0126 mol
5-2
0.981 mol
6-1
183 g/mol
6-2
2.40 g
7-1
SO2
7-2
8-1
8H+ + MnO4-  Mn2+ + 4H2O + 5e-
8-2
8H+ + MnO4- + 5Fe2+  Mn2+ + 4H2O + 5Fe3+
6e- + 7OH- +7H+ + NO2-  NH3 + 2H2O +7OH-
5-3
74 L
2.76 g/L
5(Fe2+  Fe3+ + 1e-)
5Fe2+ 5Fe3+ + 5e-
2(4OH- +2H2O + Al  AlO2- + 4H+ + 4OH- + 3e-)
8OH- + 4H2O + 2Al  2AlO2- + 8H+ + 8OH- + 6eOH- + H2O + NO2- + 2Al  NH3 + 2AlO29-1
2.50 L
9-2
10-1
86 g/mol
11-1
486 nm, visible
41.7 L
13-1a not allowed
b ground
13-2 Se
13-3 1s22s22p63s23p64s2
13-4 As
14-1 Ti, F15-1 32
15-2 ICl3, NF3
14-2 Na, Ne
c ground
d excited
14-3 K
14-4 b
15-3
15-4
15-5
15-6
SO2
SF4, BF3
3,2,0
NF3
16-1
a. polar; b. polar c. non-polar; d. non-polar
17-1 trig plane, trig pyramid
17-1 T-shape, trig pyr, bent, lin., tetrahd
18-5 SO2
19-1 sp3 , 3, 0
20-1 -761 kJ
20-1 92.4 g
22-1 -99 kJ
23-1 -189 kJ