Cem 860 Quiz 2

subject Type Homework Help
subject Pages 6
subject Words 746
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) The concentration of lead nitrate (Pb(NO3)2) in a 0.926 M solution is ________
molal. The density of the solution is 1.202 g/mL.
A) 0.770
B) 2.13
C) 1.03
D) 0.819
E) 0.650
2) Which of the following cannot be a colloid?
A) an emulsion
B) an aerosol
C) a homogeneous mixture
D) a foam
E) All of the above are colloids.
3) The formula weight of calcium nitrate (Ca(NO3)2), rounded to one decimal place, is
________ amu.
A) 102.1
B) 164.0
C) 204.2
D) 150.1
E) 116.1
4) Which one of the following is a correct representation of a beta particle?
A) e
B)
C) e
D) e
E)
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5) Cholesteric liquid crystals are colored because ________.
A) each molecule is a chromophore
B) of the slight twist between layers
C) of the large spacing between layers
D) of the large number of conjugated bonds
E) all of the molecules contain multiple benzene rings
6) It takes 258 kJ/mol to eject electrons from a certain metal surface. What is the
longest wavelength of light (nm) that can be used to eject electrons from the surface of
this metal via the photoelectric effect?
A) 464
B) 233
C) 165
D) 725
E) 552
7) Lithium and nitrogen react in a combination reaction to produce lithium nitride:
6Li (s) + N2 (g) → 2Li3N (s)
How many moles of lithium are needed to produce 0.45 mol of Li3N when the reaction
is carried out in the presence of excess nitrogen?
A) 0.23
B) 1.4
C) 0.15
D) 0.30
E) 2.7
8) How many protons are there in one atom of 71Ga?
A) 40
B) 70
C) 71
D) 31
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E) 13
9) Hydrophobic colloids ________.
A) are those that contain water
B) can be stabilized by adsorption of ions
C) are those that do not contain water
D) can be stabilized by coagulation
E) will separate into two phases if they are stabilized
10) Which hydrocarbon pair below has identical mass percentage of C?
A) C3H4 and C3H6
B) C2H4 and C3H4
C) C2H4 and C4H2
D) C2H4 and C3H6
E) none of the above
11) The bond angles in a tetrahedral molecule are ________ degrees.
A) 109.5
B) 120
C) 90
D) 45
E) <45
12) A 17.5 mL sample of an acetic acid (CH3CO2H) solution required 29.6 mL of 0.250
M NaOH for neutralization. The concentration of acetic acid was ________ M.
A) 0.158
B) 0.423
C) 134
D) 6.88
E) 0.214
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13) One mole of ________ contains the largest number of atoms.
A) S8
B) C10H8
C) Al2(SO4)3
D) Na3PO4
E) Cl2
14) Boric acid condenses to form tetraboric acid according to the equation ________.
A) 4H3BO3 (s) --> 2H2B2O7 (s) + 3H2O (g)
B) 2H3BO3(s) --> HB2O2 (s) + 4H2O (g)
C) 4H3BO3 (s) --> HB4O8 (s) + 4H2O (g)
D) 2H3BO3 (s) --> H2B4O7 (s) + 3H2O (g)
E) 4H3BO3 (s) --> H2B4O7 (s) + 5H2O (g)
15) The correct name for HBrO4 is ________.
A) hydrobromic acid
B) perbromic acid
C) bromic acid
D) bromous acid
E) hydrobromous acid
16) The pH of a solution prepared by mixing 55.0 mL of 0.183 M KOH and 10.0 mL of
0.145 M HC2H3O2 is ________.
A) 9.97
B) 7.74
C) 0.878
D) 13.122
E) none of the above
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17) The missing product from this reaction is ________.
Np --> Pa + _____
A) He
B) e
C) n
D) e
E)
18) The reaction below is used to produce methanol:
CO (g) + 2H2 (g) → CH3OH (l)³Hrxn = -128 kJ
(a) Calculate the bond energy given the following data:
(b) The tabulated value of the (C-H) bond energy is 413 kJ/mol. Explain why there is a
difference between the number you have calculated in (a) and the tabulated value.
19) Which one of the following is sodium thiosulfate?
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A) Na2SO4
B) Na2SO3
C) Na2S2O3
D) Na2S4O6
E) Na2S
20) The effective nuclear charge of an atom is primarily affected by ________.
A) inner electrons
B) outer electrons
C) nuclear charge
D) electron distribution
E) orbital radial probability

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