# CHM135H1 Study Guide - Midterm Guide: Unified Atomic Mass Unit, Diatomic Molecule, Caesium

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14 Mar 2014
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CHM139 Term Test 1 February 9, 2011
1. An element X consists of three isotopes as shown below. What is the relative atomic mass of this
element?
Abundance
Mass (amu)
Isotope 1
30.00%
40.00
Isotope 2
50.00%
41.00
Isotope 3
20.00%
42.00
a) 40.70 amu
b) 40.90 amu
c) 41.45 amu
d) 41.90 amu
e) 42.20 amu
2. The mass percentage of nitrogen in the amino acid glutamine (C5H10N2O3) is:
a) 15.4%
b) 19.2%
c) 21.8%
d) 23.0%
e) 26.8%
3. 15.0 mL of 0.100 M hydrochloric acid (HCl) is added to pure water to yield a final volume of
250.0 mL. The resulting concentration of hydrochloric acid is:
a) 1.00 x 10-3 M
b) 2.50 x 10-3 M
c) 3.32 x 10-3 M
d) 4.67 x 10-3 M
e) 6.00 x 10-3 M
4. Carbon monoxide absorbs light of frequency 1.16 x 1011 Hz, resulting in excitation of an electron
within the molecule. The corresponding change in electron energy in kJ/mol is:
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a) 0.0769 kJ/mol
b) 0.0463 kJ/mol
c) 0.926 kJ/mol
d) 4.63 kJ/mol
e) 13.9 kJ/mol
5. Cesium metal has an ionization energy of 3.894 eV and a binding energy of 206.5 kJ/mol. Would
a laser operating at a wavelength of 488.1 nm be able to eject a photoelectron from a sample of
cesium metal?
a) Yes, because the photon energy is greater than the ionization energy.
b) No, because the photon energy is smaller than the ionization energy.
c) Yes, because the photon energy is greater than the binding energy.
d) No, because the photon energy is smaller than the binding energy.
6. Which of the following sets of quantum numbers are not allowed?
n
l
ml
I
3
-1
-1
II
3
1
-1
III
3
1
2
IV
3
2
2
a) I and III only
b) III only
c) III and IV only
d) I and II only
e) II and IV only
7. When ranked from left to right by increasing first ionization energy, the correct order for the
elements Ca, Ge, Ni, and Se is:
a) Ge < Ca < Ni < Se
b) Se < Ge < Ni < Ca
c) Ni < Ge < Ca < Se
d) Ca < Ni < Ge < Se
e) Ca < Ge < Se < Ni
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