Chemistry for Engineers Homework Answers - Chapter 6

Chemistry Homework Questions Chapter 6

Which of the following pairs is incorrectly matched?
a.
Wavelength -- lambda
b.
Frequency -- f
c.
Mass -- m
d.
Speed of light -- c
e.
Planck's constant -- h


In a photoelectric effect experiment, a beam of ___Electrons________ strikes a metal surface potentially causing an ___Photon______ to be emitted.

A photon with a frequency of 2.1104 s1 has an energy of:
1.
1.41029 J
2.
1.91019 J
3.
5.11011 J
4.
6.2 1012 J

According to the Bohr model, the allowed energies of the hydrogen atom are given by the equation: E = (-21.7 x 10-19)/n2 J. What is the ionization energy, in J, for the loss of an electron from the lowest excited state?
a.
2.18x10-19
b.
5.45x10-19
c.
2.18x10-18
d.
1.66x10-18
e.
2.42x10-19


Give the number of orbitals an atom can have with the following designation:
n = 3
a.
10
b.
3
c.
5
d.
4
e.
None of these (Answer is 9)

How many orbitals are there in the 4p subshell?
a.
1
b.
2
c.
3
d.
4
e.
5

Which anion below would have the following electron configuration?
1s22s22s63s23s6
a.
Cl-
b.
F-
c.
O2-
d.
Ca2+
e.
S

How many valence electrons are there in the electron configuration for F-?
a.
1
b.
6
c.
7
d.
8
e.
9

Arrange each set of atoms in order of decreasing ionization energy1.
Be, F, C
a.
F > C > Be
b.
C > F > Be
c.
Be > C > F
d.
C > Be > F
e.
none of these

Which atom in each set has the most exothermic electron affinity?
i) N, O, Ne ii) Al, Si, Cl
a.
i) Ne ii) Cl
b.
i) N ii) Cl
c.
i) O ii) Cl
d.
i) Ne ii) Si
e.
i) O ii) Al

For which of the following types of electromagnetic radiation would the photons have the greatest energy?
a.
x-rays
b.
UV
c.
visible
d.
IR
e.
microwaves

For which of the following types of electromagnetic radiation would the photons have the lowest energy?
a.
x-rays
b.
UV
c.
visible
d.
IR
e.
microwaves

What would be the best description of Einstein's explanation of the photoelectric effect?
a.
Electrons have a definite mass.
b.
Ejection of electrons occurs when the intensity of light increases beyond a certain minimum.
c.
Light consists of "particles" with a definite mass.
d.
Light consists of "particles" with a definite energy.
e.
Ejection of electrons occurs when the energy of the photon is greater than a certain minimum.

Calculate the energy, in joules, of a photon of red light that has a frequency of 4.35 x 1014 s-1.
a.
6.90 x 10-7
b.
2.88 x 10-19
c.
4.35 x 1014
d.
1.45 x 10-19
e.
1.04 x 1027

According to the Bohr model, the allowed energies of the hydrogen atom are given by the equation: E = (-21.7 x 10-19)/n2 J. Calculate the wavelength, in nanometers, of the electromagnetic radiation required to raise an electron from the n = 3 to the n = 5 energy level of a hydrogen atom.
a.
2.34 x 1014
b.
2.34 x 105
c.
1.28 x 10-4
d.
1.28 x 103
e.
1.55 x 10-19

Which of the following sets is not an acceptable set of quantum numbers for an hydrogen atom.
a.
n = 2, L = 1,  mL= -1
b.
n = 7,  L= 3,  mL= +3
c.
n = 2,  L= 1,  mL= +1
d.
n = 3,  L= 1,  mL= -3
e.
n = 1, L = 0,  mL= 0


Which of the following set is an acceptable set of quantum numbers for an electron in a hydrogen atom? (Note: n=3 is because of excited state)
a.
n = 1, l = 1, ml= 0, ms = - 1/2
b.
n = 2,  l = 0, ml = 0, ms = 1
c.
n = 3, l = 1, ml = -1, ms = - 1/2
d.
n = 0, l = 0, ml = 0, ms = + 1/2
e.
n = 2, l = 1, ml = 2, ms = - 1/2


Give the number of orbitals for the following sublevel:
4s
a.
1
b.
4
c.
2
d.
5
e.
none of these

Which of the following subshell notations reflects an atom in the ground state?
a.
1s22s22p23s1  
b.
1s22s22p63s3
c.
1s22s22p63s23d5
d.
1s22s22p63s23d5
e.
1s22s22p6

Identify the element and give the symbols of the other elements in its group.
[Ar] 4s23d104p4
a.
Zn; Cd, Hg
b.
Cd; Zn, Hg
c.
Se; O, S, Te, Po
d.
Ga; B, Al, In, Tl
e.
none of these

Of these elements, which displays the greatest electron affinity?
1.
C
2.
Ca
3.
F
4.
Se

The following ionization energies were determined by experiment for an unknown element:
(I1= 1403 kJ/mol, I2 = 2857 kJ/mol, I3= 4580 kJ/mol,  I4= 7478 kJ/mol,  I5= 53274 kJ/mol). Which of the following elements is most likely responsible for the given ionization energies?
a.
Li
b.
Be
c.
B
d.
C
e.
N

The    Amplitude      of a wave refers to the size or height of the wave.

The energy of an incoming photon must be greater than the binding energy of the metal's electron in order to have that electron ejected from the metal's surface.
1.
True
2.
False

A X-ray photon has a wavelength of 7.2 nm. What is its energy in joules? Enter your answer in the form 1.02E12 for 1.02 x 1012 with three significant figures. Do not enter units with your answer.
0.000 +/- 3% 


One model of the hydrogen atom relies upon the idea that the electrons reside in stable orbits from which they can not deviate and are found outside of a small, densely packed group of protons. This model was created by:
1.
Niels Bohr
2.
Albert Einstein
3.
Edward Teller
4.
Julius Saulk

In quantum mechanics, an "l" value of 2 corresponds to a letter designation of:
1.
s
2.
p
3.
d
4.
f

Give the sublevel designation and the number of orbitals in the sublevel for.
n = 6, l = 3
a.
p , 3
b.
d , 5
c.
s , 2
d.
f , 7
e.
d , 7

hich element belongs to the group called the alkali metals?
a.
Mg
b.
Rb
c.
H
d.
Sc
e.
Cl

Which set of elements is not in order of increasing atomic radius (smallest one first, etc.)?

a    1.)   K+,S2-
b    2.)  K+,S2-,SE2-
c    3.)   Fe3+,Fe2+,Fe
d    4.)  F,O,O2-
e    5.)   Na+, F-,F


Which atom in each pair has the more exothermic electron affinity? 
i) K or Ca ii) Li or Na iii) Cl or Ar
a.
i) K ii) Li iii) Cl
b.
i) Ca ii) Li iii) Cl
c.
i) K ii) Na iii) Cl
d.
i) K ii) Li iii) Ar
e.
i) Ca ii) Li iii) Ar

Match each of the following wave phenomena with its definition: 
a. The bending of light waves around an object.
b. The bending of light through a series of parallel slits.
c. The separation of light into its component colors.
d. The bending of light waves at the boundary of two media.

refraction 
    D.)



As part of the quantization of light, Einstein proposed that light could behave as packets of energy referred to as:
1.
electrons
2.
nucleons
3.
photons
4.
protons

Calculate the energy in J of 0.32 moles of photons whose frequency is 2.6 x  ?
a.
1.2 x 1026
b.
1.9 x 1038
c.
1.0 x 106
d.
2.1 x 10-19
e.
3.3 x 105

Determine the number of unpaired electrons in ground state atoms of P and Cl, respectively.
a.
5, 3
b.
5, 1
c.
3, 1
d.
3, 2
e.
3, 5

Arrange each set of atoms in order of decreasing first ionization energy.
Cl, Ar, Na
a.
Cl > Ar > Na
b.
Ar > Cl > Na
c.
Cl > Na > Ar
d.
Na > Cl > Ar
e.
none of these

Successive ionization energies of the atoms a particular element increase because each additional electron is farther away from the nucleus.
a.
True
b.
False

If the binding energy of an electron in a hydrogen atom is 6.411019 J, what wavelength of photon is required to liberate it from the atom? Planck's constant = 6.626 1034 Js; c = 3.00108 m/s
1.
311 nm
2.
641 nm
3.
2.18 mm
4.
1.53 mm


The "n" value of the quantum number assigned to an orbital in a hydrogen atom best describes the orbital's:
1.
electron spin
2.
size
3.
shape
4.
orientation

How many electrons are there in a filled S orbital?
a.
2
b.
3
c.
4
d.
5
e.
6

Cobalt-60 is a radioactive isotope used to treat cancer. A gamma ray emitted by an atom of this isotope has an energy of 1.33 MeV (million electron volts; 1 eV = 1.602 x 10–19 J).
What is the frequency (in Hz) of this gamma ray?
a.
3.11 x 10–21 Hz
b.
3.11 x 10–15 Hz
c.
3.22 x 1014 Hz
d.
3.22 x 1020 Hz
e.
None of these is within 5% of the correct answer.

According to the Bohr model, the allowed energies of the hydrogen atom are given by the equation: 
E = (-21.7 x 10-19)/n2 J. An electron in the n = 5 level of an H atom emits a photon of wavelength 1281 nm. To what energy level does the electron move?
a.
3
b.
9
c.
6
d.
1
e.
None of these

What is the correct electron configuration of chlorine?
1.
1s22s22p63s23p5
2.
1s22s12p63s23p6
3.
1s22s22p63s13p6
4
1s22s22p63s23p6

How many valence electrons are there in a Te atom?
a.
2
b.
3
c.
4
d.
5
e.
6

Which of these elements has the lowest ionization energy?
1.
He
2.
P
3.
K
4.
Mg

Which of the following atoms has the most negative electron affinity?
a.
Se
b.
Al
c.
Cl
d.
Li
e.
More information is needed.




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