CHEM 110/Midterm 1

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  1. Practice Midterm #1
    1. Question 1
    2. Question 2
    3. Question 3
    4. Question 4
    5. Question 5
    6. Question 6
    7. Question 7
    8. Question 8
    9. Question 9
    10. Question 10
    11. Question 11
    12. Question 12
    13. Question 13
    14. Question 14
    15. Question 15
    16. Question 16
    17. Question 17
    18. Question 18
    19. Question 19
    20. Question 20
    21. Question 21
    22. Question 22
    23. Question 23
    24. Question 24
    25. Question 25
    26. Question 26
    27. Question 27
    28. Question 28
  2. Answers and Explanations

Practice Midterm #1

Question 1

What is the frequency associated with radiation of 4.59 x 10-8 cm wavelength?

a. 6.54 x 1017 s-1
b. 6.54 x 1015 s-1
c. 1.53 x 10-8 s-1
d. 13.8 s-1
e. 2.18 x 107 s-1

Question 2

What is the wavelength, in nm, of light with an energy content of 550 kJ/mol?

a. 0.217 nm
b. 0.419 nm
c. 157 nm
d. 217 nm
e. 6579 nm

Question 3

Select the correct statement...The photoelectric effect:

a. was discovered by Max Planck.
b. describes the phenomenon of producing a beam of electrons by shining light on any metal surface.
c. contradicted the view that light energy was dependent upon intensity only.
d. was explained by classical physics wave theory
e. results in a beam of electrons which increases in number, but not velocity, as the wavelength of
incident light decreases.

Question 4

In comparing UV and microwave electromagnetic radiation, which statement is correct?

a. Photon energy for microwave > Photon energy for UV
b. ν for UV > ν for microwave
c. λ for UV > λ for microwave
d. UV travels faster than microwave radiation in a vacuum
e. two of these statements are correct

Question 5

How many electrons would be found in the n=6 level if all possible orbitals were completely filled with electrons?

a. 18
b. 32
c. 72
d. 50
e. none of these

Question 6

The possible values of the orbital angular momentum quantum number of a 3p electron are:

a. +1/2, -1/2
b. -1, 0, +1
c. 0, 1, 2
d. 1, 2, 3
e. none of these

Question 7

The ratio of the radius of the 8 orbit of He+ to the radius of the 4 orbit for H is:

a. 1⁄4
b. 2
c. 4
d. 1⁄2
e. 1

Question 8

The ground state electron configuration of Au is:

a. [Xe] 4f13 5d9 6s2
b. [Xe] 5d10 6s1
c. [Xe] 5d9 6s2
d. [Xe] 4f14 5d10 6s1
e. none of these

Question 9

[Ar]3d10 is the ground state electronic configuration of which species:

a. Zn
b. Cu2+
c. Ge2+
d. Ga3+
e. none of these

Question 10

The quantum numbers of the last electron of Antimony (Sb) could be:

a. n = 5, l = 0, ml = 0, ms = 1/2
b. n = 4, l = 2, ml = -2, ms = 1/2
c. n = 5, l = 1, ml = 0, ms = 1/2
d. n = 5, l = 1, ml = -2, ms = 1/2
e. n = 4, l = 3, ml = 3, ms = 1/2

Question 11

The ion represented as 48Ti4+ has:

a. 22 electrons
b. 48 neutrons
c. 26 protons
d. 4 3d electrons
e. 0 4s electrons

Question 12

The orbital in which the last electron of Tantalum (Ta) is placed will have a total of how many nodes
(both radial and angular)?

a) 5
b) 3
c) 4
d) 6
e) none of these

Question 13

Which species is the most paramagnetic?

a) Cr+
b) Mn+
c) Ag
d) Fe
e) As

Question 14

Which of the following electron transitions in the He+ ion results in absorption of light of the longest
wavelength?

a) n = 8 to n = 7
b) n= 4 to n = 5
c) n = 1 to n = 8
d) n = 2 to n = 3
e) n = 1 to n = 2

Question 15

What would be the ionization energy for a B4+ ion on another planet where a high surface
temperature resulted in the third principle energy level being the ground state for the B4+ ionic under
these extreme extraterrestrial conditions?

a) 25/9 hcRH
b) -25/9 hcRH
c) 5/9 hcRH
d) -1/9 hcRH
e) hcRH

Question 16

The nth orbit of a hydrogen like species has a radius of 441 pm and an energy of
-7.84 x 10-19 J. Identify the correct H-like species and electron orbit.

a) He+, n=3
b) He+, n=4
c) Li2+, n=4
d) Li2+, n=5
e) Be3+, n=5

Question 17

For the ion Be3+, an emission line is detected at 5.816 nm. This line is due to an electron transition
from the nth orbit to the ground state orbit of this ionic species. Identify the value of n for the initial orbit
for this emission line.

a) 1
b) 4
c) 5
d) 7
e) 9

Question 18

The energy of a laser beam that excites a two-photon absorption in a particular element is 1.22x105
J/(mol of photons). What would be the wavelength of light that would excite a one-photon absorption
between the same states in the material?

a) 980 nm
b) 1960 nm
c) 490 nm
d) 8.11 x 10-31 m
e) none of these

Question 19

What would be the atomic number for the undiscovered element which would have five electrons in
its 6f orbitals?

a) 120
b) 122
c) 125
d) 157
e) 154

Question 20

Assume the Laws of Nature were different and Hund’s rule required that unpaired electrons fill
empty degenerate orbitals singly with all electrons in a spin up configuration for every atom, before a
second electron with opposite spin could be added to each orbital. What would be the outcome of the
Stern Gerlach type experiment where a beam of vanadium (V) atoms are passed through a magnetic
field?

a) The V atoms would pass through the magnetic field undeflected and produce one spot on the detector.
b) The V atoms would be deflected in two separate directions by the magnetic field and produce two
spots on the detector.
c) The V atoms would be deflected in three separate directions by the magnetic field and would produce
three spots on the detector.
d) The V atoms would be deflected backwards by the magnetic field would not reach the detector.
e) The V atoms would be deflected in one direction by the magnetic field producing one spot on the
detector.

Question 21

A US car company lists the mass of a particular model as 3142 pounds. If the velocity of the car is
measured to be u = 1.20 x 102 km/hour using a radar speed gun with a 2 % uncertainty, what is the
uncertainty (∆x) in the position of the car? (1 pound = 453.59 g)
a) ≥ 5.55 x 10-38 m
b) ≥ 3.08 x 10-43 m
c) ≥ 1.54 x 10-41 m
d) ≥ 5.55 x 10-41 m
e) none of these

Question 22

If light of a frequency of 1.50 x 1015 s-1 directed at a copper surface, electrons are ejected from the
copper and are measured to have a velocity of 7.40 x 105 m s-1. What is the work function of copper in
units of eV? (1eV = 1.602 x 10-19 J)

a) 9.94 x 10-19 eV
b) 4.65 eV
c) 6.20 eV
d) 1.19 x 10-37 eV
e) 1.50 eV

Question 23

The measured values for the work function of some metals are Al =4.19 eV, Zn=4.33 eV, Mg= 3.66
eV, Na= 2.7 eV and Cs 2.14. If light having a wavelength of 414 nm is directed on samples of these
metals, what would you expect to observe experimentally? (KE means Kinetic Energy in the answers;
1eV = 1.602 x 10-19 J)

a) electrons would be ejected by Na and Cs with KE e- Cs > KE e- Na
b) electrons would be ejected from Al, Zn, and Mg with KE e- Zn > KE e- Al > KE e- Mg
c) electrons would be ejected from Al, Zn with KE e- Al > KE e- Zn
d) electrons would be ejected from Mg, Na, and Cs with KE e- Cs > KE e- Na > KE e- Mg
e) none of these would occur

Question 24

Which is not a valid set of quantum numbers for an electron?

a. n = 5, l = 2, ml = -2, ms = 1/2
b. n = 3, l = 0, ml = 0, ms = 1/2
c. n = 10, l = 2, ml = 2, ms = 1/2
d. n = 5, l = 4, ml = 4, ms = -1/2
e. n = 6, l = 3, ml = -4, ms = -1/2

Question 25

What would be the ground state electronic configuration for In+?

a. [Kr]4d95s25p1
b. [Kr]4d105s15p1
c. [Kr]4d105s25p2
d. [Kr]4d105s25p1
e. none of these

Question 26

What would be the wavelength of an electron that is moving at 1.5% of the speed of light?

a) 74 pm
b) 162 pm
c) 52.9 pm
d) 1.62 pm
e) 7.4 pm

Question 27

How many of the following species would you expect to be diamagnetic?

Be, Cd, Cl- , Y+, Ti2+ Ag+
a) one diamagnetic species
b) two diamagnetic species
c) three diamagnetic species
d) four of them
e) all of them

Question 28

What ionic species with a 3+ charge would you expect to have the following electronic
configuration: [Kr]4d5

a) Ru3+
b) Fe3+
c) Pd3+
d) Ni3+
e) Zr3+

Answers and Explanations

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