Chem 495 Midterm

subject Type Homework Help
subject Pages 6
subject Words 846
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) Oxidation is the ________ and reduction is the ________.
A) gain of oxygen, loss of electrons
B) loss of oxygen, gain of electrons
C) loss of electrons, gain of electrons
D) gain of oxygen, loss of mass
E) gain of electrons, loss of electrons
2) Zinc reacts with aqueous sulfuric acid to form hydrogen gas:
Zn (s) + H2SO4 (aq) → Zn SO4 (aq) + H2 (g)
In an experiment, 201 mL of wet H2 is collected over water at 27 °C and a barometric
pressure of 765 torr. How many grams of Zn have been consumed? The vapor pressure
of water at 27 °C is 26.74 torr.
A) 4.38 x 106
B) 0.519
C) 519
D) 394
E) 3.94 x 105
3) What volume (mL) of a concentrated solution of sodium hydroxide (6.00 M) must be
diluted to 200.0 mL to make a 0.880 M solution of sodium hydroxide?
A) 2.64
B) 176
C) 26.4
D) 29.3
E) 50.0
4) Aqueous potassium chloride will react with which one of the following in an
exchange (metathesis) reaction?
A) calcium nitrate
B) sodium bromide
C) lead nitrate
D) barium nitrate
E) sodium chloride
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5) The concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in
200 g of C2H6O is ________ M. The density of the solution is 0.79 g/mL.
A) 21
B) 0.93
C) 0.58
D) 6.0 x 10-4
E) 1.72
6) The correct ground-state electron configuration for silver is ________.
A) [Kr]5s24d9
B) [Kr]5s14d10
C) [Kr]5s24d10
D) [Xe]5s24d9
E) [Xe]5s14d10
7) Calculate the work (kJ) done during a reaction in which the internal volume expands
from 19 L to 48 L against an outside pressure of 2.5 atm.
A) -7.3 kJ
B) 17 kJ
C) 7.3 kJ
D) -17 kJ
E) 0 kJ; No work is done.
8) Elements in group ________ have a np6 electron configuration in the outer shell.
A) 4A
B) 6A
C) 7A
D) 8A
E) 5A
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9) The formula weight of lead nitrate (Pb(NO3)2) is ________ amu.
A) 269.2
B) 285.2
C) 317.2
D) 331.2
E) 538.4
10) Of the following species, ________ has the largest radius.
A) Rb+
B) Sr2+
C) Br-
D) Kr
E) Ar
11) Of the following elements, ________ is the most easily oxidized.
oxygen
fluorine
nitrogen
aluminum
gold
A) oxygen
B) fluorine
C) nitrogen
D) aluminum
E) gold
12) Propane (C3H8) reacts with oxygen in the air to produce carbon dioxide and water.
In a particular experiment, 38.0 grams of carbon dioxide are produced from the reaction
of 22.05 grams of propane with excess oxygen. What is the % yield in this reaction?
A) 38.0
B) 57.6
C) 66.0
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D) 86.4
E) 94.5
13) Of the following transitions in the Bohr hydrogen atom, the ________ transition
results in the absorption of the highest-energy photon.
A) n = 2 → n = 5
B) n = 4 → n = 2
C) n = 3 → n = 2
D) n = 5 → n = 2
E) All transitions absorb photons of equivalent energy.
14) Hydrocarbons containing carbon-carbon triple bonds are called ________.
A) alkanes
B) aromatic hydrocarbons
C) alkynes
D) alkenes
E) olefins
15) Calculate the pH of a solution that is 0.322 M in nitrous acid (HNO2) and 0.178 M
in potassium nitrite (KNO2). The acid dissociation constant of nitrous acid is 4.50 x
10-4.
A) 3.093
B) 3.607
C) 14.26
D) 10.91
E) 4.589
16) Aqueous solutions of a compound did not form precipitates with Cl-, Br-, I-, SO4
2-,
CO3
2-, PO4
3-,
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OH-, or S2-. This highly water-soluble compound produced the foul-smelling gas H2S
when the solution was acidified. This compound is ________.
A) Pb(NO3)2
B) (NH4)2S
C) KBr
D) Li2CO3
E) AgNO3
17) Which pair of elements would you expect to exhibit the greatest similarity in their
physical and chemical properties?
A) H, Li
B) Cs, Ba
C) Ca, Sr
D) Ga, Ge
E) C, O
18) The primary buffer system that controls the pH of the blood is the ________ buffer
system.
A) carbon dioxide, carbonate
B) carbonate, bicarbonate
C) carbonic acid, carbon dioxide
D) carbonate, carbonic acid
E) carbonic acid, bicarbonate
19) The effect of a catalyst on an equilibrium is to ________.
A) increase the rate of the forward reaction only
B) increase the equilibrium constant so that products are favored
C) slow the reverse reaction only
D) increase the rate at which equilibrium is achieved without changing the composition
of the equilibrium mixture
E) shift the equilibrium to the right
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20) The value of ΔH° for the reaction below is -72 kJ. ________ kJ of heat are released
when 5.5 mol of HBr is formed in this reaction.
H2 (g) + Br2 (g) → 2HBr (g)
A) 144
B) 72
C) 0.44
D) 198
E) -72

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