116 Exam I
Name: ILE'{
Feb. 13,2014
Chem
ID#
1. Choose the correct expression
Fe(s) +
for Kc for the reaction:
COr(g) <+ FeO(s) + CO(g)
^ fr-t =-[FeO][CO]
n.
[Fe][COrJ
'
sdirls )on't aff-ar
tvr nl ur li brir'r'rn cor,49(,r,.[
"- [cor]
[co]
B. 71
_ rcot
6"
"
\/
[cor]
"-
D. K.
E. K^ -
"
Jeanne McHale
P,O
pcq
Pr"oPro
Pr"Pco,
2. The reaction 2CHo(g.) <+ CrH, (g) + 3H, (g) takes
place at 2000 K.
A reaction
mixnrl
initiatly contains only CII+ at a concentation of 0.115 M. At equilibrium the concentation of
CzHz is 0.0352 M. Find the value of the equilibritrm constant lic at this temperature.
@
z.ot x lo-2
8.4.37 x
10-3
C.5.61 x
ld
D. 1.78 x
10-3
8.9.37 x l0-3
3. The reaction C(s)+
L
I c*\
. r15 tt
L -C osszlL
E
, 0'1ftb,,
lQ=
C.tlz f
oc)
. olf L ll
.035L
bll
z-
3C.03ftl1
. I O.t6
[ct1$,
)
c. 0tr961
-
HrO(g) <+ CO(g) + Hr(S) is endothemric. Which of &e following
conditions favors the formation of more CO and Hz?
A. Temperature and pressure have no
effect ad >
O
K"
or Ke
B. High temperature and high pressure
C. Low temperature and low pressure
D. Low temperature and high pressure
-s.
(g.hign
\-/
temperature and low pressure
lcurP ft^v ors
"f$orL
rnOles
t ao1\
sid0 4^r',+h-
oe 30s
4. For which of the following reactions arc Kg
A. CaCOr(s)
<+ CaO(s) +
B. Nr(S)+3Hr(g)
e
and Kp equal?
COr(g)
2NHr(g)
(9"u",rou(s)+6or(g)<+6cor(g)+6Hro(/) An s O
D. CO(s)+Clr(g)
+>
COCIr(s)
E. H2O(/) + SOr(g)
e
HrSOn(/)
5. Given the following reactions and their equilibrium constants:
NrOr(g)
<+
NrO(g) +2Or(g) Kc =23
Nror(g)+Or(g)
<+
NrOr(g) K, = 0.55
Find the equilibrium constant for the reaction NrO(s) + Or(g)
Nro
@o.ozr
B.
+ W-
13
c.42
Ung
D.0.024
e NrOr(g)
K.= h
t702 NG
vc=k-
Nr01 )0u
+ 0L -+ Nr0s
,
E.3.6
6. The equilibrium constant K"for the reaction 2NOr(g) <+ NrOu(g) at room temperature is
0.270. Starting from an initial concentration ofNOz of 0.250 M, find the final concentration of
both reagents.
A. [NO2] :0.157
*
6NzO*l = 0.0134
M
B. tNO2l = 0.239M, [NzOa] :0.0054 M
C.
tNorl:0.005 M, [NzO+] :0.100 M
@^or r:
E. tN0rl
t
?
N0
0.0070
O
_lts
,TS +F
C
E
M
Nr0r
,?5o
a.223M, [Nzo+] = o.ol34 M
:0.273M, [NzOr] :
u u'
ILC
+ ,/y.)
r
.)l(,o6rtry
L
il,A81 ^ l,T1 ?( + .0lb8l { sO
X
T
t M?qy7
t N0,3-
--
A
--,ll
(,?{ -}r-T
.
r
1'n*l
r= h,,l't1
,'01r'1
[
*.
-, o
lbcf
qiv 4
l= (r,l.luI r,o5^f,0/ v"e
tN0l1
rnrn
7. Tlrereaction 2SOr(g) + Or(g)
e 2SOr(g) has equilibrium
constant
Kp:
0.355 at 950
K. If
these three gases ate present with the following partial pressures:
*'
[r;;']itr;J;=',-,i'ffi
i::;' H
"j't
:ilffff"-T;:y tr,,
A. The reaction quotient p is smaller than Kp and the reaction will proceed to the left.
B. The reaction quotient Q is smaller than Kpand the reaction will proceed
C, The reaction quotient
@llh"
E.
Q:
oeo
p is larger than Kpand the reaction will
rt
fSO,
to the right.
right. (1
,
proceed to the
reaction quotient Q is larger than Kp and the reaction will proceed to the
L
6
',- '.Tl9
uF
P5O3
left. a-
Kp andthe reaction is at equilibrium.
SI
atv'a
@
-
o
.
q_ - (rt)
-- )r(
(Jsr)'('s )
8. Which of the following statements about equilibrium are true?
l. At equilibrium the forward and reverse reactions stop
2. At equilibrium the rate of the forward reaction equals the rate of the reverse reaction
3. At equilibrium there is no net change in the concentrations of the reagents
A.
I
and 3 are true
B. Only I
is true
C. Onlv 3 is true
(-<\
O. ) Z and 3 are true
E. None of these
statements are true
9. The equilibrium
constant
Kr
for the reaction 2NO,
(g) <+ 2NO(g) + O, (S) is 6.5 x 10{ at
450"C. Find Kc (yes, K6 not Kp) forthe reaction NO, (S) +> NO(g) *
temperature. Usefulinformatior: -R:0.0821
x
l0{
A.
1.3
B.
l.l x l0-7
C. 2.5 x l0-3
Kf
krl.
D. 2.0 xl02
@r,
x
ro{
K,c
Vc
Ec
Lafinmol-lK
1,and
,'- [4c (KT) o^
rl) =
]
O, 19; ut
thi*
f inK:Tin"C+273.15.
6-s le3 K
+ 0z() )
'{5oo
)
= Z-J =
^/v
Kp
= (.o8ll x l)b){ tt.Sx/ou)
" [*r)-on
= t.0qs X lo-1 .ew 2N0.-; )Nl 0 t0,
2N0r
I
2
(r.otr X/d')u'
N0r;
(
[^
d0,
+ (p +i0-
10. Which of the following statements about the effect of a catalyst on equilibrium is true?
A. A catalyst makes the reaction more thermodynamically favorable
B. A catalyst shifts the position of equilibrium toward the side with fewer moles of gas.
,61A catalyst shifts the position of equilibrium in the endothermic direction
G h catalyst has no effect on the position of equilibriunL
\lr.
it just allows equilibrium to be reached
rapiity.
E. A catalyst changes the value of the equilibrium constant.
I 1. For the reaction HCOOH(aq) + HrO(/) +> HCOO- (aq) +HrO* (aq)
A
( A)UCOOH is an acid and HCOO-
is its conjugate base.
B. HCOOH is an acid and HzO is its conjugate base.
C. H:O* is an acid and HCOO- is its conjugate base.
D. HzO is an acid and HCOO- is its conjugate base.
E. HCOO-is an acid and HCOOH is its conjugate base.
12. When
BF: combines withNH: to form the
\i
adduct: ro*'f-\'-,,,
FH
A. BF3 is acting as a Lewis base and NHs is acting as a Lewis acid.
6lbr,
is acting as a Lewis acid and NHr is acting as a Lewis base.
Ieors GCiA
'
*'(*f
P\,'
(-'
I-a'*,r
= e'
i.l br^ra
P,f dolf
C. BFI is acting as a Bronsted-Lowry acid andNHr is acting as a Bronsted-Lowry base.
D. BF: is acting as a Bronsted-Lowry base and NH: is acting as a Bronsted-Lowry acid.
E. BF: is acting as an electron pair donor and NH: is acting as an electron pair acceptor.
13. Which of the
following pairs of acidare both strong acids?
A. HCIOr and HCIO+
B. HCI and HF
and HNO3
LCJJHCI
D. CH:COOH and HzSO:
E. HzSOn and HzS
14. The pH of a l0-8
M solution of HCI in water is
A. Slightly greater thanT
@u**
t A+1 = lo'1 Yl
a\^to i^iz Lhrrn
tessthan 7
C. Exactly 8
JtS
of
[to*
Nater
D. Exactly 6
E. Exactly 7
15. Phosphoric acid HsPOa is a triprotic acid where Kol is the dissociation constant for the first
fftuql + HzPO+ (aq), Ko2 is that {or the second step H2PQ+ (aq) ff(uq)
FIPOa2-(aq), and Kos is that for the third step ttpo+2-(aC)
rflag pbo"(uCl. What ir ttr"
relationship among the magnitudes of these three dissociation constants?
step: tI:POa(aq)
A.
&t:
)
Koz= Kos
h
arotrr \u ntrno\e Il\
frcrw'
G *gy6ue 15 Ct.at5eo( AC iA
B.KalKoz<&s
C.IQr > K"z=
*
)
i
+
Kos
D. Ku > Koz < K,s
I\7-'E-lK^, ) -az
K-,) --uJ
K-,
16. HNOz has K" = 4.0
x 10-4. Find the pH of a 0.50 M solution of HNOz.
A. 0.30
B. 3.40
c.
I tt N0'rf
10.60
so\r^tror-
Cilr.ae
E. 2.45
17. 20.0 mL of 0.100 M HCIO, \Mith
pH at the endpoint of the titration.
iS f
&:2.9
:
8.3.82
c.8.54
8.7.68
L t{
U.01. to[+-l '-
U0 io1 )
f
r
l(n
LC4P-1
,,tO
. aJbl
,t+*1
x l0-8, istitrated with 0.200 MNaOH. Findthe
rvra{r: arv)' =
@ro.rr ),vrdfci,,rt
(?o'o,^L)c'l t'l
'
D.5.46
-r -F
L
t ilr7t N0;1
vwle
):
)
bulc-
Vg (,r n
)
, = J'0 rnrvr"l6
Vg = lo.0 n"L ;k; odu{oal
t|ro ?-7 Hu! ry) t-otl''
a
)?:l: =o S.qsxro' . ,Haollot{-].
.
=
).O nrr'v'oie
- 7.
I
=L
18.
A solution is 0.50 M in acetic acid, CHTCOOH, and 0.50 M in sodium acetate CH:COONa.
K,for
acetic acid is 1.75 x 10-5. The pH ofthis solution is
@ru
pA
8.9.24
c.7.00
.
,
D.3.45
8.8.27
19. Acid #1 has
K,=
1.5
x
Fr(o
Plr^
10-5 and acid #Zhas
'%W
. -13[l']'f,/i-)
+
o
Ko:2.7 x
10-3. Consider solutions of the same
concentration of either acid.
A. Acid #2has a smaller percent ionization and a smaller PIQthan acid #1.
(ry/ecia #2hasa
larger percent ionization and a smaller plQthan acid #1.
C. Acid #zlws a larger percent ionization and a larger pKnthan asid#|.
D. Acid #2has a smaller percent ionization and a larger plQthan acid#|.
E. Acid #2has a larger plQthan acid#l,but the percent ionizations are the same.
20. Consider five indicator
acids, with color changes over the following pH ranges. Pick the
indicator that would be best for the titration of a strong acid with a strong base.
A. Cougar crimson pH 2.4 - 3.9
( B.)Bromoseltzer
blue pH 6.5
C. Husky yellow pH
8.9
-
-8.2
9.5
D. Methyl green pH 1.5 -2.6
E. EthylvioletpH 10.5 -12.0
21. Calculate pH and pOH of a solution containing l0 M NaOH
A.pH: 15, pOH = I
B.pH: 14, pOH = 0
(9ptt:
D.pH =
15,
1,
poH:
-l
pOH = 13
E.pH = 2, pOH:
12
P0t+
=
frt++
-l-,,,:lO -- -
'F+l l'f
|
22. Arrange the oxyacids of chlorine in the order of increasing acid stength
A. HCIO: < HCIOz < HC1O < HCIOI
B. HCIO+ < HCIOg < HCIO2 < HCIO
C. HC1O < HCIOa < HCIO3 < HCIOz
@Hcro
< HCloz < HClor < HClo+
E. HCIO < HCIO3 < HCIOz < HCIO+
23. KtforNHr is 1.8 x l0-5. Find
A.g.2x
@t.u
10-ro
fifotNl{4*.
l{o'
x ro-ro
/x
.--./
Kw,
/, trF/O
Vv
C.4.7 x 10-7
/D-t{
-r
D. 8.5 x l0-7
E. 1.8 x 10-re
plLo-: 5,{Z
24. Anacid HA has & = 3.0 x
10-"4.
20.0 mI.of a 0.100 M solution of this acid is titrated with
0.100 M NaoH, what is the pH after 5.0 mL of base has been
added? .\
,)
rI
nnol
lY
A
6;:' ti; $: : 'HIt;'fr-ffi=);,?'l-T'drrv'r
C.3.5
D.
10.0
8.4.0
l++ +
0l+- -) l.l,o r
ledues l,'i"tS mmte
;;i'="
25.The percent ionization of a 0.100
A. 5.0 x
#A ,oi'ol
,
rn
/.
unpkle rc2rhon
7l1rms '0''f nn& 4
c
- r,s, r
^"';""tg"ibiirr;"
f*
M
tuy#,
solution of acid HA is 5.0o/o. Find
l0{
=[L++1
'00tvl
'0s('t00m)'
'
8.2.6xr0-6
c.3.2xtr7 Lt-1fr7 -* ,l0O 14 - , 005 14 : ,0?{
IA-1
14
@z'ox
loa
t/
I , (,,,or)'
T*41
(,0?s)
I
t
Helpful Information
i
Kp:
Kc&If
I
pH:
-logfifl
K*: ttfltOfl :
pOH =
1.00
x
-loglOFl pI(*: *loeFa pI(:
10-14
l{o!fi: K*
:
;
pH +
pOH:
14
plq+ pIG:
PY = nRT
pKo= pH
+r"fffi
1
aft =l@ton
R
:0.0821 L ffi mofr K-r
14
-logKo