Chemistry 106: General Chemistry
Syracuse University Project Advance
Exam #2, Fall 2010
Name
Date
The last page of each examination is a periodic table.
c = 3.00 x 108 m/sec
h = 6.63 x 10-34 Js
mp = 1.67 x 10-24 g (mass of proton)
Rydberg Constant (RH) = 2.18 x 10-18 J
(1)
Hydrogen peroxide, H2O2, can be prepared in a process whose overall change is:
H2(g) + O2(g) ------> H2O2(l)
Calculate the enthalpy change for the reaction above using the following data.
H2O2(l) ------> H2O(l) + 1/2 O2
2 H2(g) + O2(g) ------> 2H2O (l)
(a)
(b)
(c)
(d)
(e)
(2)
H
H
= -98.0 kJ
= -571.6 kJ
-670 kJ
-474 kJ
-523 kJ
-384 kJ
-188 kJ
Ethanol (molar mass = 46.05 g/mol), C2H5OH, is mixed with gasoline and sold as
gasohol. Use the following to calculate the grams of ethanol needed to provide
293 kJ of heat:
C2H5OH(l) + 3 O2(g) ------> 2 CO2(g) + 3 H2O(g)
(a)
(b)
(c)
(d)
(e)
CHE 106
H
= -1235 kJ
10.9 g
21.8 g
32.7 g
43.6 g
54.5 g
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Fall 2010 Exam #2
(3)
Phosphoric acid, H3PO4, can be prepared by the reaction of phosphorus(V) oxide,
P4O10, with water
1/4 P4O10(s) + 3/2 H2O(l) ------> H2PO4(aq)
H
= -113.2 kJ
What is H for the reaction involving 1 mol of P4O10?
(a)
(b)
(c)
(d)
(e)
(4)
Which one of the following will have the greater kinetic energy?
(Hint: Think KE equation)
(a)
(b)
(c)
(d)
(5)
+113.2 kJ
+28.3 kJ
-28.3 kJ
-452.8 kJ
-905.6 kJ
A 10 kg object traveling at 5 m/s.
a 5 kg object traveling at 10 m/s.
both of these have the same kinetic energy.
not enough information is provided to answer the question.
Given that Hf for MgCl2 is -641.6 kJ/mol and Hf for KCl is -435.9 kJ/mol,
calculate Hrxn for the following equation:
2 K(s) + MgCl2(s) ------> 2 KCl(s) + Mg(s)
(a)
(b)
(c)
(d)
(e)
(6)
Hrxn
=?
+205.7 kJ
-205.7 kJ
+230.2 kJ
-230.2 kJ
+1077.5 kJ
The heat capacity of copper metal is 0.38 J/g °C. Assume you had a 75 g cube of
copper at 25° C. What would the final temperature of the copper be (in °C) if it
absorbed 150 J of heat?
(a)
(b)
(c)
(d)
(e)
CHE 106
19.7
5.3
30.3
25.8
38.2
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Fall 2010 Exam #2
(7)
A chemical reaction that absorbs heat from the surroundings is said to be
and has a
value of H.
(a)
(b)
(c)
(d)
(e)
(8)
Which of the following sets of quantum numbers is/are possible for an electron in
an atom?
I.
II.
III.
(a)
(b)
(c)
(d)
(e)
(9)
endothermic, positive
endothermic, negative
exothermic, negative
exothermic, positive
isothermic, zero
n = 4, l = 4, ml = 3, ms = +1/2
n = 1, l = 0, ml = 0, ms = -1/2
n = 2, l = 0, ml = -2, ms = +1/2
None are possible
I and II
I
II
III
Given the thermodynamic data in the table below, determine the H° for the
following reaction.
C2H5OH(l) + O2(g) ----------> CH3CO2H(l) + H2O(l)
H° = ?
Substance
H°f (kJ/mol)
C2H4(g)
52.3
C2H5OH(l)
-277.7
CH3CO2H(l)
-484.5
H2O(l)
-285.8
NH3(g)
-46.0
CO2(g)
-393.7
(a)
(b)
(c)
(d)
(e)
CHE 106
-79.0 kJ
-1048.0 kJ
-476.4 kJ
-492.6 kJ
none of the above
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Fall 2010 Exam #2
(10)
55.0 grams of water at 69.0° C is added to an unknown amount of water at 22.0° C,
The final temperature of the water is 31.0° C. How many grams of water were
there initially at 22.0° C? (The heat capacity of water is 4.18J/g K)
(a)
(b)
(c)
(d)
(e)
(11)
Which of the following statements is/are correct?
I.
II.
III.
The reaction vessel cools when an endothermic reaction occurs.
An exothermic reaction is characterized by a negative value of H.
Heat is evolved when an exothermic reaction occurs.
(a)
(b)
(c)
(d)
(e)
(12)
I only
II only
I and II only
II and III only
All are correct
What is the molar heat capacity of heptane, C7H16, if its specific heat is
2.25 J/(g°C)?
(a)
(b)
(c)
(d)
(e)
(13)
232
13.0
0.077
55.0
4.31 x 10-3
175 J/(mol °C)
200 J/(mol°C)
225 J/(mol°C)
250 J/(mol°C)
300 J/(mol°C)
The reaction shown below is
and therefore heat is
2 Al(s) + 3 O2(g) ------> 2 Al2O3(s)
(a)
(b)
(c)
(d)
(e)
CHE 106
by the reaction.
H° = -3351 kJ
endothermic, absorbed
endothermic, evolved
exothermic, absorbed
exothermic, evolved
none of these
4
Fall 2010 Exam #2
(14)
Indium compounds emit a blue-violet color when placed in a flame. The emission
responsible for this blue-violet color has a wavelength of 451 nm. Calculate the
energy of a single photon of this wavelength.
(a)
(b)
(c)
(d)
(e)
(15)
How many unpaired electrons are in a ground state atom of phosphorus?
(a)
(b)
(c)
(d)
(e)
(16)
13
10
6
3
0
What is the wavelength of light emitted when the hydrogen atom undergoes a
transition from level n = 5 to level n = 2? (RH = 2.180 x 10-18 J)
(a)
(b)
(c)
(d)
(e)
(18)
0
1
2
3
None of the above.
The number of core electrons shielding the valence-shell electrons of an atom of
aluminum from the nucleus is:
(a)
(b)
(c)
(d)
(e)
(17)
2.99 x 10-40 J
1.47 x 10-27 J
4.41 x 10-19 J
2.99 x 10-31 J
1.47 x 10-36 J
663 nm
833 nm
546 nm
521 nm
434 nm
The square of the wavefunction, 2, of an electron in an atom
(a)
(b)
(c)
(d)
(e)
CHE 106
describes the energy of the electron.
specifies the momentum for the electron.
gives the probability of finding the electron in a region of space.
is proportional to the velocity of the electron.
is inversely proportional to the distance between the electron and the
nucleus.
5
Fall 2010 Exam #2
(19)
From the Bohr model of the hydrogen atom, we can conclude that the energy
required to excite an electron from the n = 2 to the n = 3 level is
the
energy to excite an electron from the n = 3 to the n = 4 level.
(a)
(b)
(c)
(d)
(e)
(20)
All of the following statements about quantum numbers are true except
(I wrote “One” next to the 1’s .. the rest are “L’s”)
(a)
(b)
(c)
(d)
(e)
(21)
n
3
4
3
I only
II only
III only
I and II only
II and III only
l
3
2
2
ml
1
1
1
ms
-1/2
-1/2
+1/2
Which quantum number distinguishes the different shapes of the orbitals?
(a)
(b)
(c)
(d)
(e)
(23)
n has integral values from 1 (one) to infinity.
l has values from 1(one) to infinity.
m has 2l + 1(one) values
m has values of +1 to -1, including zero.
s has values of + 1/2 and - 1/2.
Which of the following combinations of quantum numbers are permissible?
I.
II.
III.
(a)
(b)
(c)
(d)
(e)
(22)
less than
greater than
equal to
either equal to or less than
either equal to or greater than
m
n
s
l
all of these
What is the maximum number of electrons in the n = 3 quantum level?
(a)
(b)
(c)
(d)
(e)
CHE 106
3
5
7
9
18
6
Fall 2010 Exam #2
(24)
From a consideration of electronic configurations, which of the elements indicated
below would be classified as a TRANSITION element?
(a) 1s2, 2s2, 2p2
(b) 1s2, 2s2, 2p6, 3s2, 3p5
(c) 1s2, 2s2, 2p6, 3s2, 3p6, 4s2
(d) 1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s2
(e) 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6
(25)
What is the electron configuration of Ni2+?
(a)
(b)
(c)
(d)
(e)
(26)
Which of the following atoms has the smallest atomic radius?
(a)
(b)
(c)
(d)
(e)
(27)
Sr
Mg
P
I
Ne
Which of the following atoms designated by electronic configuration has the
highest ionization energy?
(a)
(b)
(c)
(d)
(e)
(28)
[Ar] 3d64s2
[Ar] 3d74s1
[Ar] 3d8
[Ar] 3d84s2
[Ar] 3d84s1
[Ne] 3s23p2
[Ne] 3s23p3
[Ar] 3d104s24p3
[Kr] 4d105s25p3
[Xe] 4f145d106s26p3
Which one of the following elements would be expected to have the largest atomic
radius?
(a)
(b)
(c)
(d)
(e)
CHE 106
Li
Cs
F
Br
I
7
Fall 2010 Exam #2
(29)
In general, atomic radii
(a)
(b)
(c)
(d)
(e)
(30)
All of the following is isoelectronic (isoelectric) except
(a)
(b)
(c)
(d)
(e)
(31)
S2Ar
K+
Cl-1
Na+
How many unpaired electrons are there in a ground state atom of selenium (Se)?
(a)
(b)
(c)
(d)
(e)
(32)
decrease from left to right in a period and increase down a group.
increase from left to right in a period and decrease down a group.
increase from left to right in a period and increase down a group.
decrease from left to right and decrease down a group.
None of the above.
1
2
3
4
none
Which of the following statements about the alkali metals (Group 1) is not correct?
(a) Electron affinities decrease going down the group (from smaller to
larger elements).
(b) Ionization energies decrease going down the group (from smaller to
larger elements).
(c) Chemical reactivity decreases going down the group (from smaller to
larger elements).
(d) The second ionization energy for each one is much greater than the first
ionization energy.
(e) Each one can attain a noble gas configuration by losing an electron.
(33)
Which of the following atoms has the smallest atomic radius?
(a)
(b)
(c)
(d)
(e)
CHE 106
Sr
Mg
P
I
Ne
8
Fall 2010 Exam #2
(34)
The 1s subshell is much closer to the nucleus in argon than in helium due to
(a)
(b)
(c)
(d)
(e)
(35)
nuclear charge
paramagnetism
diamagnetism
Hund’s rule
the azimuthal quantum number, l
Which one of the following elements has the largest second ionization energy?
(a)
(b)
(c)
(d)
(e)
CHE 106
K
Rb
Sr
Ca
H
9
Fall 2010 Exam #2