Chemistry11
/l
":;';$:il,
kr,
Narne: /{,Vo,
Section
rh
(1) if a solutionshowspositivedeviationsfrom Raoult'slaw, would you expectit to havea
higheror lower boiling point thanif it wereideal? Explain.
(+) leviJi^ +
+L^ .xf'cl.,L.q L;,l,^j
?uT b hrSLon
F,*+ ?y,?U^
lo G.(o^r. 1 (I,rul lo rrorLP.l--p
EriL^1
/ !J!{
(2) The solubilityof benzoicacid (find structurein textbook)is 0.34 g per 100 mL in watcr at 25
'C.
"C andis 10.0g per 100mL in benzene
(CoHo)at 25
Explainthis behavior.Wouldbenzoic
acidbe more or lesssolublein 0.1 M NaOFIsolutionthanit is in water? Explain.
8 <auic
aeil
cqa
7:^ o. t t4 Naotl. lAo,u it 6n
Cr4tcoTl + olt' -)
a",Jfhos,tx/"."
^
CrHrcoT+Hro
l
T h e r r l o r - 5 < n z o t c d crt l
is t o(L sol-l\, in $av
( 3 ) A s o l u t i o n o fs o d i u m c h i o r i d e i n w a t e r h a s a v a p o r p r e s s1u9r e
. 6otfo r r a t 2 5 " C W
. hatis
the mole fractionof NaCl in this solution?What would be the vaporpressureof this solutionat
45 "C? The vaporpressureof wateris 23.8torr at 25 "C and7L9 torr at 45 "C.
/,ro
:
l' f ol''lr;-
- * * - =
lL
i o
/ nt r v o
X s , t ^ ] . tl - 7 1 1 , r ' #
qq ,lEoc,
2 3t,
: o.tz4
r J <^'
o
N"ct 7 90("l
rLy
? , ( o . r z t ) ( r ( . ? { " , r )t
fi.Lfiorr
o.7t
r-l t Vinegaris 5.0% aqueousaceticacid solutionby mass. If the densityof householdvinegaris
1.UI g mL. find the mole fraction,molarity,andmolality of this aceticacid solution. The
tornrulafor aceticacidis HC2H3O2.
tl7J
llts,*,- tool tolulti^ => {l llcLltDv 6n,l ?fJ ll? j=
.)
Lotj l*,
/1
ff o3 Hro
:3:I
ly o 5f*_"1
7Y*1
^^t Hl
H-o
: f zy
Krc.Hroo
t'!
Lo.orJ/uot
H ; b'D83
= D.t4A
,
:
/oo
'"r
:
6.on
l
:
D.' otr3
u
-u'
- =
-
o.4f
jl.al ^L so/.1;,u
t
D- D(3 --,( IlQtlro,
o'otl
b.ofi + f.4
= o. ot{
-E--
O . 8 1" ^
(5) A solutionis prepared
by mixing 50.0mL of toluene,C7II8(d:0.867 glmL),with 125mL
:0.874
g/ml). Assurningthat the volumesadd upon mixing, find the mass
benzene,CoHo(d
percent,mole fraction,molality,and molarityof the toluene.
to^L Cfs ^ oYLlt,
$.tf,
C-,Ht
tv:. L
lz{ *u CrH,, o!( S : lot.zsX 7H"
(vrL
^.qrr (cru") , {3!1
_
7
r l o t zt
tf}.ls + lof:15
rt,-,rr'
;:-
(3'\/tz.tt_
-
,eqz
o.z{
r v 1-
O ' ' 1 7* ^ o l
t,l,. -) u
:
o.(o1.t-{lsJ:
(' -f -iu. t r , l o 7 , z { - - F
+
ftl3
/t't t
f"I =
2. Y? *ol
Z L . L 1M
b. tlf L
-'--
(6) Which solvent,wateror hexane(CoHr+),would you chooseto dissolveeachof the
followins?
a, Nacl {lg
b. HF #LD
c. octane(CsHrs) O
-c'H.
lrl
d. o{H1)2soo
#r,
e. aceticacid
f. cupric
nitrate ,H,
.
' LO
HP
(7) The normalboiling point of methanolis 64.7'C. A solutioncontaininga nonvolatilesolute
dissolvedin methanolhasa vaporpressureof 710 tor at 64.7 "C. What is the mole fractionof
methanolin this solution?
)
(sJ'.h,*-
4t
x
=
1 ' S o l vA
=
_--
'D .
5o(n.^I
(8) What is the composition(in mole fraction)of a pentane-hexane
solutionthat hasa vapor
p r e s s u r e o f 3 5 0 t o r r a t 2 5 " CW?h a t i s t h e c o m p o s i t i o n ( i n r n o l e f i a c t i o n ) o f t h e v a p o r i n
of pentaneand hexaneare 5l I and
equilibriumwith this soh"rtion.At 25 "C the vaporpressllres
I 50 torr, respectivcly.
D
+ AHIH
r{"(o
I
,^
,(
\
- t{o
E11
IIJ
P(; (o r) (rt,)
/
D. {{
t - 7 f - " b'Y{
h,
^
3ro - lfo
- ' =
i - - - - :
tr
ug
prt"
'a
tol
7o'-
lo[J';*
L
x,?i r (t-rp)Pu
4 - 1 b , Y g o
I tol
/
t
ttt' L/ o . , t g. / l\/ t f o- )/ =
:
7J('{or,
17.{{./,
xf'
Ltt
: 6-tt
.'-
+
7*l + 11.{
<-
0t7
(9) A flask containinesolid NH4CIbecomescolderas wateris addedandthe saltdissolves.
of NH+CIin waterexoor.(A-"tn.-r?ry Why doesthesaltdissolve?
a. Is thedissolving
.
\__/
AHI*) il f-,rll 6nJ cc.nlr. r-yj,.,l
b. Is the magnitudeof AH1ox1..
of Nu*@\r
Explain.
\__/
\
!or/o-r.ul,Ur,
smallerthanthe AHhyd,.ution
of the ions?
-Ml+I t',r,
LHr,t
0)
- I .
(1 0 )
a. Usethelollowingdalato calculate
thecombined
heatsof hydrationlbr theionsin potassium
bromate (KBrO:): AHturti..: -745 kJ/rnol
: 41.1 k.l/mol
AHsolution
IH rot= AH,+ oU^J^
A H , '- A [ 1 . +
b f t f = - U . 1 ,d+i l r o f
'
r t'{5 'll't =
+
1
?03'7 Lt/*,"t
-----:--
b. Which ion do you think contributesmoreto the answerto parl (a)? Why?
( trr ),t s,^q(1.t
lln^* 7r0i so il ut// lr."-
\-'/
lnt5"rcha'5-4*t
(11) Which ion in eachpair hasthe greaterchargedensity?Briefly explaineachanswer.
u(O,
\J
.r'
bGi) or Rb*
\--/
(r,g", ch"lo
f,'-<lla, V
=;f cD
=) fa>
c (a)or ct.
\-/
9^'11" V
=/?6
( l2) You are given a bottleof solid X andthreeaqueoussolutionsof X, one saturated,
one
unsaturated
and one supersaturated.
How would you determinewhich solutionis which?
A,l"t d l*.(( Q-n''^Jb{ toli,l.x L ,oL, Tl* x u(l( ,\u1 }6r,(,o
'rl,
In 1l^- {ol'r^lr/ trJ ;
*t l[ Jt {nluil d,^.lL. ,^r,-t<lc,rJ.,o
s,l,J,L .
t
'fL aLlc)
X uitl( (t,zg. M,/L of lh. g-fwsal.Jol*l,i l"
pru,p.(^{..
(13) You wantto convcrtamongmolarity,molality,andmole fractionola solution.You know
the massesof soluteand solventandthe volumeof the solution. Is this enoushinformationto
carryout all the conversions?Explain.
fo^ uil
lt
t'toaz,4{,
Jr."
C'^tcrl l. t,
b^vc,l
Lclr.rn
,roo[)' A<t& 'il^L
^"[.r*J
a^,L u,:lu(ll, <*"1vicz ,/<{fa,
^r>1..{^Atbb( U^
lol"rJ J.