CEM 420 Midterm 1

subject Type Homework Help
subject Pages 7
subject Words 962
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) The majority of glucose molecules exist in ring structure.
2) Nitrogen is colorless because the minimum energy to excite an electron is in the
ultraviolet section of the spectrum.
3) The color of hemoglobin changes from purple to red when water displaces oxygen on
the molecule.
4) Units of energy include newtons, joules, and calories.
5) Water is considered to be a diatomic molecule because it is composed of two
different atoms.
6) Positron emission causes a decrease of one in the atomic number.
7) The overall reaction order is the sum of the orders of each reactant in the rate law.
8) The effective nuclear charge acting on an electron is larger than the actual nuclear
charge.
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9) Electron domains for single bonds exert greater force on adjacent domains than the
electron domains for multiple bonds.
10) As electronegativity difference increases, bond length will decrease.
11) The solubility product of a compound is numerically equal to the product of the
concentration of the ions involved in the equilibrium, each multiplied by its coefficient
in the equilibrium reaction.
12) Sulfur compounds in the atmosphere are equally derived from natural sources and
from human activity.
13) A great deal of the carbon dioxide produced by the combustion of fossil fuels is
absorbed into the oceans.
14) The electron density of the 2s orbital is asymmetric.
15) The effective nuclear charge in an atom is proportional to the number of nuclear
protons.
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16) Calculate the molarity of a 10.0% (by mass) aqueous solution of hydrochloric acid.
A) 0.274 m
B) 2.74 m
C) 3.04 m
D) 4.33 m
E) The density of the solution is needed to solve the problem.
17) The molecular geometry of the BeCl2 molecule is ________, and this molecule is
________.
A) bent, nonpolar
B) linear, polar
C) bent, polar
D) seesaw, polar
E) linear, nonpolar
18) Calculate the pH of a solution prepared by dissolving 0.270 mol of formic acid
(HCO2H) and 0.260 mol of sodium formate (NaCO2H) in water sufficient to yield 1.00
L of solution. The Ka of formic acid is 1.77 x 10-4.
A) 2.099
B) 10.264
C) 3.736
D) 2.307
E) 3.952
19) Based on molecular orbital theory, the only molecule in the list below that has
unpaired electrons is ________.
A) C2
B) N2
C) F2
D) O2
E) Li2
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20) Based on the figure above, the boiling point of water under an external pressure of
0.211 atm is ________ oC.
A) 60
B) 40
C) 70
D) 80
E) 90
21) What is the charge on the complex ion in Ca2[Fe(CN)6]?
A) 3-
B) 2+
C) 2-
D) 1-
E) 4-
22) What is the frequency (s-1) of electromagnetic radiation that has a wavelength of
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0.53 m?
A) 5.7 X 108 s-1
B) 1.8 X 10-9 s-1
C) 1.6 X 108 s-1
D) 1.3 X 10-33 s-1
E) 1.3 X 1033 s-1
23) What happens to the mass number and the atomic number of an element when it
emits gamma radiation?
A) The mass number remains unchanged while the atomic number decreases by one.
B) The mass number decreases by four and the atomic number decreases by two.
C) The mass number increases by four and the atomic number increases by two.
D) The mass number remains unchanged while the atomic number increases by one.
E) The mass number and atomic numbers remain unchanged.
24) The formula weight of potassium dichromate (K2Cr2O7 ) is ________ amu.
A) 107.09
B) 255.08
C) 242.18
D) 294.18
E) 333.08
25) The first ionization energies of the elements ________ as you go from left to right
across a period of the periodic table, and ________ as you go from the bottom to the
top of a group in the table.
A) increase, increase
B) increase, decrease
C) decrease, increase
D) decrease, decrease
E) The first ionization energies of the elements are completely unpredictable.
26) The equilibrium-constant expression for a reaction written in one direction is the
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________ of the one for the reaction written for the reverse direction.
27) Why is cyclopropane more reactive than propane?
28) The contribution of sulfur to acid rain is via the production of ________.
29) The binding of molecules to the surface of a catalyst is referred to as ________.
30) Name the compound, Ca[AlH4]2.
31) The chelate effect is enhanced by polydentate ligand binding because of the change
in ________.
32) What is the pH of a sodium formate (NaCHO2) solution prepared by adding 0.680
grams of sodium formate to 100.0 ml of water at 25.0 oC? The Ka at 25.0 oC for formic
acid is 1.8 x 10-4.
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33) Electron pairs surrounding the carbon atoms in alkanes are in a ________
arrangement.

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