Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
Constants/Conversions
C=3.00 x 108 m/s
1 amu= 1.66054 x 10-24 g
h = 6.626 x 10-34 JS
1 Cal = 4.184 J
1 L atm = 101.325 J
k = 1.38066 x 1023 J/K°
e =1.602 x 10-19 Coul
N(Avagodroe's number) = 6.02214 x 1023
R = 8.3145 J/K°mol = 0.082058 L atm/ K°mol
760 torr = 760 mm-Hg = 1atm = 1.01325 x105 Pa
1 J = 107 erg
RH = 2.18 x 10-18 J
o
1 A = 10-8 cm = 102 pm = 10-1 nm
1 eV = 96.45 kJ/mol
Equations
E = hv C= vλ
1
En = (-RH) 2
n
E = hc/λ π = MRT
λ = h/mv
ΔH Vap
P
q
Specific Heat =
ln ( 1 ) = P2
m ⋅ ΔT
R
⎛1
1 ⎞
⋅ ⎜⎜ − ⎟⎟
⎝ T1 T2 ⎠
K = °C + 273.15
ΔT = kfm
R1/R2 = (M1/M2)-1/2
Ln A = ln A0 -kt
KP = KC (RT)Δn
EΨ = HΨ
ΔE = q + w
ΔT= kbm
q = CΔT = n CΔT = m s ΔT
+
E ∝ (Q Q)/d
nλ = 2d⋅sinθ ΔG = ΔH -TΔS
t1/2 = 0.693/k
k = A⋅exp(-Ea/RT)
KaKb = Kw = 1 x 10-14
1/A = 1/A0 -kt
[base]
2.303 ⋅ RT
pH = pKa + log(
) ΔG = ΔG° =RT⋅ ln (Q) E = E° ⋅log (Q)
[acid]
nF
Ecell = Ered + Eox
Fe3+ + e- → Fe2+
E° = + 0.771
2+
F = 96,485 Coul/mol
Cu + 2e → Cu(S) E° = + 0.337
ΔS°rxn = ΣnΔSf°(products) - ΣmΔSf°(reactants)
ΔG = -nFE
ΔH°rxn = ΣnΔH°f(product)-ΣnΔH°(reactant)
P1 = χ1PTotal
1A
8A
1
1
2
H
He
1.008 2A
3
4
2
Li
3A
5
Be
3
Na
K
Mg
Ca
5A
7
C
6A
8
N
7A
4.003
10
F
Ne
9
O
10.81 12.01 14.01 16.00 19.00 20.18
13
14
15
16
17
18
Al
22.99 24.31 3B
19
20
21
4
6
B
6.941 9.012
11
12
4A
Sc
4B
22
5B
23
6B
24
Ti
V
Cr
7B
25
Mn
26
Fe
8B
27
Co
28
Ni
1B
29
2B
30
Cu
Zn
Si
P
S
Cl
Ar
26.98 28.09 30.97 32.07 35.45 39.95
31
32
33
34
35
36
Ga
Ge
As
Se
Br
Kr
39.10 40.08 44.96 47.90 50.94 52.00 54.94 55.85 58.93 58.70 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
5
Rb
Sr
Y
Zr
Nb
Mo
Tc
85.47 87.62 88.91 91.22 92.91 95.94 (98)
55
56
57
72
73
74
75
6
Cs
Ba
La
Hf
Ta
W
Re
Ru
Rh
Pd
Ag
Cd
Os
Ir
Pt
Au
Hg
132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 192.2 195.1 197.0 200.6
87
88
89
104
105
106
107
108
109
110
111
7
Fr
Ra
(223) (226)
Ac
Rf
Ha
Sg
Ns
(227) (261) (262) (266) (262)
58
6
Ce
59
Pr
60
Nd
61
Pm
In
Sn
Sb
Te
I
Xe
101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3
76
77
78
79
80
81
82
83
84
85
86
Hs
Tl
Pb
Bi
Po
At
204.4 207.2 209.0 (209) (210)
Rn
(222)
Mt
(265) (266)
62
Sm
63
Eu
64
Gd
65
Tb
66
Dy
67
Ho
68
Er
69
Tm
70
Yb
71
Lu
140.1 140.9 144.2 (145) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0
90
91
92
93
94
95
96
97
98
99
100
101
102
103
7
Th
Pa
U
Np
232.0 (231) 238.0 (244)
Pu
Am
Cm
Bk
Cf
(242) (243) (247) (247) (251)
Es
Fm
Md
No
Lw
(252) (257) (258) (259) (260)
1
Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
molecule
CH4(g)
N2H4(l)
HF (g)
N2O(g)
O3(g)
CO(g)
NO2(g)
CO2(g)
H2O(g)
H2O(l)
ΔHf˚
-74.8
50.4
-135.6
81.5
143.0
-110.5
33.8
-393.5
-241.8
-285.8
2
Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
MULTIPLE CHOICES (60)
1. Which of the following sets of quantum numbers is NOT permissible?
A. n = 1, l = 0, ml = 0, ms = + 12
B. n = 4, l = 0, ml = 0, ms = +
1
2
C. n = 3, l = 3, ml = –3, ms = –
D. n = 2, l = 1, ml = 1, ms = –
1
2
1
2
2. Which one of the orbital occupancy designations shown below does NOT make sense?
A. 2s1
B.
3d10
C. 4p7
D. 4f7
3. The n and l quantum numbers of the “last” electron of an element are n = 5 and l = 1. The
A. transition element.
B.
alkali metal.
C. metal or a nonmetal.
D. alkaline earth element.
4. The maximum number of electrons that can occupy the 5f orbitals is
A. 6.
B.
10.
C. 14.
D. 18.
5. The total number of electrons in p orbitals in a silver atom is
A. 6.
B.
12.
C. 18.
D. 24.
6. Which of the following electron configurations is NOT possible?
A. 1s2 2s2 2p6
B. 1s2 2s2 2p2
C. 1s2 1p2
D. 1s2 2s2 2p6 3s1
7.
Which of the following electron configurations represents an excited state?
A.
B.
C.
D.
He: 1s2
Ne: 1s2 2s2 2p6
Na: 1s2 2s2 2p6 3p1
P: 1s2 2s2 2p6 3s2 3p3
8. Rank the following regions of the electromagnetic spectrum in order of increasing energy.
x rays, microwaves, infrared, ultraviolet
A. x rays, microwaves, infrared, ultraviolet
B.
microwaves, infrared, ultraviolet, x rays
C.
microwaves, ultraviolet, infrared, x rays
D. infrared, microwaves, ultraviolet, x rays
3
Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
9. Which of the following elements has the smallest ionization energy?
A. F
B.
Be
C.
B
D. Mg
10. Which of the following elements has the highest third ionization energy?
A. Al
B.
Ga
C. Mg
D. As
11. Which one of the following elements would be expected to have the LARGEST atomic radius?
A. Li
B. . Cs
C.
F
D. Br
12. Calculate the energy (joules per particle) of a photon of wavelength 22.5 nm.
A. 1.13 x 10-17
B.
1.13 x 10-13
C.
8.84 x 10-15
D. 8.84 x 10-18
13. What is the energy of ONE MOLE of photons with a wavelength of 285 nm?
A. 3.50 x 10-18 J
B.
3.15 x 105 J
C. 4.20 x 105 J
D. 2.11 x 106 J
14. Which of the following statements is (are) TRUE?
1. The product of wavelength and frequency of light is a constant.
2. As the energy increases, the frequency of the radiation decreases.
3. As the wavelength of light increases, the frequency increases.
A. 1 only
B.
2 only
C.
3 only
D. 1 and 3 only
15. The square of the wave function, ψ2, of an electron in an atom
A. gives the probability of finding the electron in a region of space.
B.
describes the energy of the electron.
C.
specifies the momentum of the electron.
D. is proportional to the velocity of the electron.
16. Einstein’s work on the photoelectric effect provided support for the equation
A. K.E. = 1/2 mυ2.
B.
E = hυ.
C.
E = mc2.
D. λ = h/mv.
4
Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
17. All the following statements about the quantum numbers are true EXCEPT
A. n has integral values from 1 to ∞.
B.
l has values from 1 to ∞.
C.
ml has 21 + 1 values.
D. ms has values of + 12 and − 12 .
18. The contribution for which de Broglie is remembered in modern science is
A. his statement that an electron can exist in an atom only in discrete energy levels.
B.
his statement that no electron can have identical values for all four quantum numbers.
C. his proposal that particles of matter should be associated with wavelike behavior.
D. his statement that elements show periodic repetition of properties.
19. The ground-state electron configuration of a Fe3+ ion is 1s2 2s2 2p6 3s2 3p6 3d5. Therefore, Fe3+ is
A. diamagnetic.
B.
paramagnetic with one unpaired electron.
C.
paramagnetic with three unpaired electrons.
D. paramagnetic with five unpaired electrons.
20. Which of the following atoms has the SMALLEST atomic radius?
A. Sr
B.
Mg
C.
I
D. Ne
SHORT ANSWER (20 pts)
1. Definition. (5 pts)
A. Hund’s rule
B. the effective nuclear charge
C. Van der Waals radius
D. isoelectronic
E. electronegativity
2. Please briefly describe photoelectric effect and conclusion by Albert Einstein
16 -1
3. When light of frequency 2.30 x 10 s shines on the surface of cesium metal, electrons are ejected
with a maximum kinetic energy of 9.2 x 10-19 J.
f
KE
=
9.20E-19 =
IE
=
2.30E+16
hv
1.52E-17 1.43E-17
What is the ionization energy in kJ/mol?
KE 9.20E-19
IE
IE
4. Please briefly explain the factors and the trends of ionization energy
5
Foothill College
Chem1A01 Exam3A
July 30, 2009
Name:
LONG ANSWER （10 pts each）
1. Gaseous lithium atoms absorb light of wavelength 287.3 nm. After absorbing this light, lithium atoms
return to their ground state by emitting two photons with λ= 842.5 nm and 850.9 nm the remainder of the
energy is lost as heat . Calculate the fraction of the energy lost as heat, and draw an energy level diagram
that shows this process.
E(abs)
hc/λ(287.3)
6.92E-19
q
Fraction
=
=
=
=
=
E(em)
hc/λ(842.5) +
2.36E-19 +
2.22E-19 J =
0.32
hc/λ(850.9) + q
2.34E-19 + q
1.41E+02 kJ/mol
2. Ionization energy is the minimum energy required to remove an electron from an atom and is expressed in
kJ/mol.
a) Calculate the ionization energy for the hydrogen atom when electrons are removed from n= 3.
b) Calculate the ionization energy for the hydrogen atom.
ΔE = -RH [(1/nf2) – (1/ni2)]
2 pts
-18
b. (1/nf2) = 0, ΔE = -RH = 2.18 x 10 J/atom
2 pts
2.18 x 10-18 J/atom x (1 kJ/1000 J) x (6.02 x 1023 atom/mole)
= 1312 kJ/mol
J/atom
a. ΔE = -RH [(1/nf2) – (1/ni2)] = -RH [ 0 – 1/9] =
J/atom x (1 kJ/1000 J) x (6.02 x 1023 atom/mole)
=
kJ/mol
2 pts
2 pts
2 pts
6