FH, Chem1C, Sum 09, FH, Lee ExamFinal
~k~£=4y-----------
Name
Read the questions carefully to understand it, before answering on the question paper. Write clearly and concisely. Use the
reverse side of your answer paper as scratch. The last page contain a periodic table and some important constants. pH =
pKa + log ([Conj. Basej/[Acidj]:
P A = XApO A ; llTf=Kf.m; IT= MRT; E = EO - (RT/nF) In (Q); llGO = - nF EO = - RT InK;
In(Nt/No) = - kt; (Total pts.= 109 + 3*27 = 190).
SHORT ANSWER.
To get full points, show all your work in details with set up equation
1) The Ksp for Zn(OH)2 is 5.0
x
10-17. Determine
the molar solubility
buffer solution with a pH of 11.5 (8 pts.).
-!..: "(,
,
Z.« ( Ok)'/.. (~)
2- 5
-
"L02+CC;ii
-;::::
and units.
of Zn(OH)2 in a
1)
-1"2-
5.0
\
"f
\ ()
t,\
2
.•... 0H-u{.)
"
2
Ksp
==
z:
[Zn'>J
~o~1
n H",
(3,! ~
,=
-.l
\
0 - ;;) ')
5
2) Calculate the percent ionization
acid. The acid dissociation
of nitrous acid in a solution that is 0.249 M in nitrous
constant of nitrous acid is 4.50
x
l[ • '2 C, .;: _
2)
10-4 (8 pts.),
\ 0 -- ,(,~
1.
H ND z. (CQ ~
c. '2. 1..19 ",.,
~
o
o
0" ~
"" x.
'I
r
3) A solution is prepared
resulting
by dissolving
15.0 g of NH3 in 250 g of water. The density of the
solution is 0.974 g/mL. Calculate the molarity of NH3 in the solution (8 pts.).
yY\oloofN\-\
~
(,oJ
15
:::
i ,r
c.7: -
i"'t-f
~O.S~2rA~
j"_-11-.5
...f_
y
r-
e, . 'J
fI
~
/
c-
z . 43 11
j
1
J
_'...'
-.l_"
(J
J
3
t1
L-13 __
3) _~---=::....-
4) A solution is prepared by adding 30.00 g of lactose (milk sugar) to 110.0 g of water at
55°C. Calculate the partial pressure of water above the solution in torr. The vapor
pressure of pure water at 55 °C is 118 torr. The MW of lactose is 342.3 glmol (8 pts.).
,,"ole .fyq+lv,'
r
0"1
'
CNd-<-'f
( l0
-=
__
0 /
.J_
\~
5
\loJ/''f~t''c{-'+
,.,.d-.
4)
_
)Oj734.2.3j",,~-f
/
5) The standard
emf for the cell using the overall cell reaction below is +2.20 V:
2AI (s) + 312 (s) ~
2A13+ (aq) + 61- (aq)
Calculate the emf (in V) generated
M (8 pts.).
r:
t;::..
cdl"
..
= 4.5 x 10-3 M and [1-] = 0.15
'2- ,z0j
0
Q r\....0.-::<
J...
?. S " C )
by the cell when [AI3+]
CO
~
cc».
-T
_:J_- . Cl
S~
'"
'2. 2i-2.. V
6)
6) Calculate how many seconds are required to produce 1.0 g of silver metal by the
electrolysis of a AgN03 solution using a current of 30 amps (8 pts.).
9 b l{ ~o ~
I rv-c-i
"2
893.3C
'£"C).3>
.z:
C
z:
P""P'"
3,0
;,pc
~ See.
1~,1-% see.
2
7) Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope
The half-life of strontium-90 is 28.8 yr. What percentage of a strontium-90
remains after 70.0 yr (8 pts.)?
uranium-235.
sample
18 . s ~'/.
7)
_ Kt
•- G 1}--_.: -+
-
-{ II
_
_
. Gq
rt
NL::
z.
3
f
><
?-O
0.'65(;
;:;..
,
'l..
o
9
8) A rock contains 0.313 mg of lead-206
for the decay of uranium-238
years
is 4.5
t-n
\,
?b-206,10Wc1
x
of uranium-238.
The half-life
t,ci3
,£<q 2>
-=:. _
(i-;<!),~\3)<~)~
~~~~~~~
~
t
'f.
1t5)(IO~
Q
t
U-'2.3&,
cr-
t, y2. -.q .sX fO
0
_
10
;;;(.00-,(
8)
.693
k=---
_';(.1
z:
1~
of
109 yr. Calculate the age of the rock in
.
J(\ D
U-2 ~8" ~?<--ed uJ ,-\JA
o.3\2>~
to lead-206
(8pts.).
\ V\ ~f'.E:... $::vV'tf ,Q.. (0 Q.. ~OJJ-e
\~
for each milligram
~,oO
')C,.ID
~'
wseJt~ 0lr \)- '23% +to*- ~
O.'3.\.3,~
~
?b-2.06 ::::..D.313)(;;8
OM~
(\+
\
6
""oj
u..)Q.
\
~~t)-..vs
,3\~)(
\j-2%? (N~\
9) How much energy is lost or gained when a mole of Co-60 undergoes
beta decay:
6027Co -> 0 -1 e + 6028Ni?
tr\o...s;s
The mass of the 6027Co atom is 59.933819 amu, and that of a 6028Ni atom is 59.930788
amu. (Mass of an electron: 5.4858 x 10-4 amu) (10 pts.).
-I.\:
XL 60 Co ~e»..&-=-s-q.g338.\9a..'N\U-d7)(
S-.48,S1S'1-\o
q\"{)u.) '::::"S'l.9\9ao7Q.vnl.(
27
-\j'
~~
~
W\Cl.S
W\~:o,s: c5b- ~N ~ ~-VJ.h
~
~
r=-o-y 1
S
or 0.. ~
0
"2-7
-l
cuY;,
-T bDtJ·
A.y{\:::::
I
2~
or- o.J..cm 'I-
\o..W\tA.-?> \~
?.
\.t
'v"
<b-c
= - 3. D3 DA'2
-= c.a..
)
5. 4'658:A \(4)
-6
'j
0
¥:5
:3o'30A 2
(2,'1 -'Cf
'6
Oy~)
= 5"4·'9 \ 5 Lt 28' ~ 'IY)\i
d.Vi\!
-S9.qt~oo7
C::::U'f'
_ ~
==-_"3.1J~O\..\21.\O ~
)(~
-D,0030?OIk_o-'f.
\
:.S Vt'\
eJ.~
(5.4<65%,x'o4-\-5q.q\Sl\-2~
::: _ c>)no
~\M:=:
6}
vY\.CA.s s
<"),
y.1'\.Q\~)
bE::::. j),W'.c
~~
~
W\
• q 3078% - :A2>
=~ct
6cG,~
-=
ICJb1)t-
. ~
7<-0 ~
I
d.o72 x
•
:J
10
G vJ ~ ~,7 2 X
\!
0
J
[,S?JJ.::>
~-r ~ ~
~~I\
~
3
twJ ~~
I) \ 'rQ-I.A
VN);J
~
4r
10) (A) Write the electronic configurations next to each species (eg. [Ar] 3dn) (2 pts./each)
and then (B) decide if it is paramagnetic or not (1 pts/each) (total 15 pts.):
cr3+
r 1 3 d.~
W· r >. r_ • r, r J,c
LA
5
n ~•.c:
,
rAy;
Cu+
r A r7
...
Lj
.s 1-
)-"\~-
3cl'O
II c
••..
I
0:',., ~
t
Ji ~-.,-e
f
[)"
I
\!I
cIx-:
' ,
J1:
cJ..,:'
_1
.i.
~
d.:; JF
j
,
dr'l
r~tc
. r--t ..
c.
•.... c r-
c..1Ie
-1f
clx
dXr
/1--- ~
u
I
~~~
tJ
~
d~?
l
"Xl
d"
d"
.1L-1i
\7
,b?-
D.
I
-""di
1.
.J.L~
cl ;>
J
p) L-,;
Lo~-.5p;r
it"
1L-
-;rx~
sp
ell:
dx'_ ~:
P<A.
P) 110
Ii' \ Sp;(\
'C
-J
L{
(:.1]2
_
r
Co
11) (A) Draw d-electron energy splitting diagram and d-electron distribution in following
complexes ( 4pts/each) and then (B) circle the correct statement if the complex is
paramagnetic (Para) or diamagnetic (Diamag) (1 pt/each) (totaI20pts.).
.-1
11)
Y cL'0
Zn
Ca
_
)
[r< rj
Ag+
10)
~rc·,,_~O'("'.
,
d;n.
P --: L\sp
L-Ov.,.,_Spi"
-
1\ -
[CoF6]3-
[Co(CN)6]3-
[NiCl4]2-
[Ni(CN)4]2-
(tetrahedral)
para;@iam~
~Diamag
MULTIPLE CHOICE. Choose the one alternative
(Square planer)
8/Diamag
para/E~~
that best completes the statement
or answers the question (3 pts each).
12) Which of the following could be added to a solution of sodium acetate to produce a buffer?
acetic acid
hydrochloric acid
potassium acetate
A) acetic acid or hydrochloric acid
B) sodium chloride or potassium acetate
C) potassium acetate only
D) hydrochloric acid only
E) acetic acid only
4
sodium chloride
12)
_A_
13)
_C__
14) Which below best describe(s) the behavior of an amphoteric hydroxide in water?
A) With cone. aq. HCl, its clear solution forms a precipitate.
B) With cone. aq. NaOH, its suspension dissolves.
C) With cone. aq. HC!, its suspension dissolves.
D) With cone. aq. NaOH, its clear solution forms a precipitate.
E) With both cone. aq. NaOH and cone. aq. HCl, its suspension dissolves.
14)
_E_
15) Which one of the following is most soluble in water?
A)CH3CH2CH2CH2CH20H
15)
E_
13) In which of the following aqueous solutions would you expect AgCl to have the highest
solubility?
A) 0.020 M BaCl2
B) 0.015 NaCl
C) pure water
D) 0.020 AgN03
.\)'\..
E) 0.020 KCl
B) CH3CH2CH20H
C) CH3CH20H
D)CH3CH2CH2CH20H
E) CH30H
16) The concentration
mass.
A) 3.50 x 101
B) 3.50
x
10-2
C) 3.50
x
10-6
D) 3.50
x
102
E) 3.50
x
10-3
of chloride ion in a solution that contains 35.0 ppm chloride is
% by
16)
17) As the concentration of a solute in a solution increases, the freezing point of the solution
____
and the vapor pressure of the solution
_
A) decreases, increases
B) decreases, is unaffected
C) increases, decreases
D) increases, increases
E) decreases, decreases
17)
18) Which of the following liquids will have the lowest freezing point (take care for Vant Hoff factor)?
A) pure H20
18)
B) aqueous FeI3 (0.24 m)
C) aqueous KF (0.50 m)
\
D) aqueous glucose (0.60 m) • ~
E) aqueous sucrose (0.60 m)
10
5
E
C
_
19) Consider
an electrochemical
2H+ (aq) + Sn (s)
cell based on the reaction:
--+
19)
C
Sn2+ (aq) + H2 (g)
Which of the following actions would not change the measured cell potential?
A) lowering the pH in the cathode compartment
B) increasing the tin (II) ion concentration in the anode compartment
C) addition of more tin metal to the anode compartment
D) increasing the pressure of hydrogen gas in the cathode compartment
E) Any of the above will change the measured cell potential.
Table 20.2
Half- reaction
cr3+ (aq) + 3e-
--+
Cr (s)
-0.74
Fe2+ (aq) + 2e-
--+
Fe (s)
-0.440
Fe2+ (s)
+0.771
Fe3+ (aq) + eSn4+ (aq) + 2e20) The standard
--+
--+
Sn2+ (aq)
cell potential
+0.154
(EOcell) for the voltaic cell based on the reaction below is
_
20)
r]J _
21)
A_
22)
_C_
23)
E_
V.
2Cr (s) + 3Fe2+ (aq)
A) +0.83
21) The standard
reaction is
B) +2.80
cell potential
3Fe (s) + 2Cr3+ (aq)
C) -0.16
D) +0.30
E) +3.10
(EOcell) of the reaction below is +0.126 V. The value of 6.GO for the
kJ/mol.
Pb (s) + 2H+ (aq)
A) -24
--+
--+
pb2+ (aq) + H2 (g)
B) +24
C) -12
22) By what process does thorium-230
A) beta emission
B) positron emission
C) alpha emission
D) gamma emission
E) electron capture
D) +12
decay to radium-226
----?
23) Of the following processes, which one changes the atomic number?
A) electron capture
B) alpha emission
C) positron emission
D) beta emission
E) All of these processes change the atomic numbers.
6
E) -50
24) Nuclei above the belt of stability can lower their neutron-to-proton
A) beta emission.
B) electron capture.
C) gamma emission.
D) positron emission.
E) Any of the above processes will lower the neutron-to-proton
ratio by __
24)
ratio.
25) The missing product in this reaction combines with oxygen to form a compound with the formula
42 _
K
19
,.{'
'{>o
~:(~<~
l\<0
°e+
-1
25)
<D _
----
A) M0:2
D)MO
26) Bombardment of uranium-238
____
neutrons.
A)1
with a deuteron (hydrogen-2)
B) 2
C)3
generates neptuniurn-237
D) 4
and
26)
_C_
E) 5
E
27) If we start with 1.000 g of cobalt-60, 0.675 g will remain after 3.00 yr. This means that the half-life
of cobalt-60 is
yr.
A) 3.08
B) 2.03
C) 4.44
D) 7.65
E) 5.30
27)
28) Which one of the following can be done to shorten the half-life of the radioactive decay of
uraniurn-238?
A) freeze it
B) convert it to UF6
28)
---
29)
---
---
~
C) heat it
D) oxidize it to the +2 oxidation state
E) none of the above
29) This reaction is an example of
41C
20 a -
41K
+ ---19
A) electron capture
B) gamma emission
C) alpha decay
D) positron decay
E) beta decay
7
30) Carbon-l1
decays by positron emission:
30)
_C_
31)
_A~
r'
l1C
6
--;. l1B + 0 e
5
1
The decay occurs with a release of 2.87
undergoes this radioactive decay,
A) 3.48
x
105
B) 1.28
x
10-2
C) 1.16
x
10-3
D) 1.16
x
10-6
E) 8.62
x
102
x
1011
J per mole of carbon-ll.
g of mass is converted
31) The largest number of stable nuclei have an
number of neutrons.
A) even, even
B)odd,odd
C) odd, even
D) even, equal
E) even, odd
number
32) The mass of a proton is 1.00728 amu and that of a neutron
(in amu) of a ~~ Co nucleus?
A) 27.7830
33) The coordination
A) 4
_
is 1.00867 amu. What is the mass defect
C) 0.0662
of cobalt(ill) and of chromium(ill)
B)3
C)2
34) During the formation of a coordination
A) Arrhenius bases
B) Br0nsted bases
C) Arrhenius acids
D) Lewis acids
E) Lewis bases
35) Changes in the coordination
A) stability
B) color
C) physical properties
D) chemical properties
E) all of the above
of protons and an
(The mass of a cobalt-60 nucleus is 59.9338 amu.)
B) 0.4827
numbers
When 4.00 g of carbon-l1
to energy.
compound,
E) 0.5405
in their complexes
are always
D)6
sphere of a complex compound
8
---
.?
D) 0.5489
ligands act as
32)
33)
E) 5
_
may lead to changes in
_
34)
E
35)
E
36) Based on electron configuration,
which is most likely colorless?
36)
C
37)
C
A) [Cu(NH3)4]2+
B) [Cr(NH3)sCl]2+
C) [Cd(NH3)4]2+
D) [Ni(NH3)6]2+
E) [Co(NH3)6]2+
...
37) Which of the following is a polydentate
A) chloride ion
B) water
C) oxalate ion
D) ammonia
E) hydroxide ion
ligand?
38) How many d electrons are in the cobalt ion of K3[Co(CN)6]
C)S
B)7
A)6
D) 3
39) (BONUS) Which one of the following is a strong-field
C) ci-
B) F-
A)NH3
40) (BONUS) Which transformation
A))<C~ -? C~042-
could take place at the anode of an electrochemical
x?
7<,"->
-?
<>
C)~
-I
-?
D) V~+
H2~
-?
,"v
E) NO
'
H3As03
v02+
x<,
-+
NO:r
9
38)
f\
39)
.9
E) 4
ligand?
D)CN-
0
B) H2As04
?
E) H20
cell?
40)