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Chem 167 Exam 3 Review
l. Given the electronegativities below, which covalent bond is
most polar?HCNO
Electronegativity: 2.1 2.5 3.0 3.5a. C-H 0.t1b. N-H 0.1n o-H
i,Lla. o-c I'be. O-N 0't
Among the following molecules, only ispolar.a- BeClzb. CBr+0
ur,d. Alclre. Cb
Draw lewis structures forthe following molecules. Give the shape
of themolecule, hybridization of the'dentral atom, andthe bond
angle(s).
a. CP,q,f.'z tu- cr,:t: +Arehdrelispl ,10q.5,
:?:b. OFz
J.
"6.,,t! )ri,],Pol3', ).
i q,l - l'\', rDI j'. )^BCt3 -: ,,id,
r'p1s'g-i '
btt#; Q3i *uq s'
BeFz
:i * SL-L'
PBr5 ',9i,'I
'- htynd lqrnmici*li t1:3, < [0Q,5,'hgtlnnl plunar; sf ;
lro.
.f: linrur;si,; 1t0'
,.5'\ - ,l:' ';$1, - g.i,
{ilunu} hiprymidc-f i\T i {$'/rto'
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5.
4. The total number of o bonds in the H-C:C-C:C-C=C-C=N molecule
isa.4b.6@sd. t2e. 15
In ethylene (HzC:CHz), the C{ double-bond results *orn ( overlap
of-ill orbitals *d tlf overlap of D orbitals on th" C atoms.ta.
orsp,7[,p \
b. o, sp2, zu, sp2c. o, sp3, fi, sO o, .p1, n,pe. fi, sp", o,
p
which drawing represents a r bonding molecular orbital for a
homonucleardiatomic molecule?
" l0
7. which of the following molecular species is stabilized by
resonance?
^,\..,vl ,\
d)e
,.' N-= r,l- rVl r{- Ntra nl
N= A/, d H- C= N:
ft\to B ,tr burds : rmh d lrille ban/,\us 1,4Y hnds
8. What is the coordination number for (a) simple cubic (b)
body-centered cubic
SC"- b$CC=8
DTB
a. COz(tl Nr-X sH,d. Or''e. HCN
9. Nickel crystallizes in a face-centered cubic lattice. If the
densrty of the metal is8.908 glcff,what is the unit cell edge
length in cm?
193"u H^-* =P:l4hua'ugla*m)x4 rtor4q = l'fiqql10"1'9I 0. Draw *J
#Jo"*. gdlk*r{$*[ooe.,"tor, semi-conductor, and insulator.
IU@vs
S&fili-
TL
il$ffirlq
corrcluftc
@\Jt
8,qM g -q,bq(rw!u(13
____v
LordiltlDcinsuirdor
,(.grl't xta-L1ed
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c
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17. Write the formation reaction for CaCOr.
Cnts) + C c,) r /"[ a CAm s (s)18. Silane, SiII+, burns
according to the teaction, SilI4 + 2 Oz ) SiOz + 2 H2O, with
AHo = -1429 kJ. How much energy is releaseci if 15.7 g of silane
is bumed?AHy ftu/ rxn
1{n6t * lfld_ts 'l4L1wlb,,TA llflq r l{not X lW ll,t v E-,t'r,rr
v"'|r /r zM n l@]Hq A lrrnmn19. Find the AHo,,* for C2H6@) + 712
Oz(S) t 2 CO{S) + 3 H2O(g)
AH"rCz[Ir(g) = -84.2 kJ/molAHor COz(g) : -393.5 kJ/molAHi HzO(g)
: -241.8 kJlmol
[t* -345,5 rynobt(gd -Lq1,g u{/mo,} -
20. How much heat must be removed to change 75.0 grams of water
at25.A "C to iceat -35.0 oC? AHo6,s;oo ice :-333.55 J/g; specific
heat of ice :2.03 Ilg"C
tt*-Wl qmrD
0 5 rrruDr = ('tbg\(q,$rlf/\Cyar\ = -Y,?Ll Ed@ {,frxAl'lrugion ?
\6yr 394'!g = -L5- 01ld@ L=nc{:_ (12h (L, og dlyh( sb, b a - i, z 3
rrv -L1-ffia n yr7
21. Determine the final temperature kfr6ilTdT-fof aluminum at
130.0 "C mixes with200.0 grams of water at25.O "C. The specific
heat of aluminum is 0.901 Jlg oC.(Coffee cup calorimeter
problem.)
(At = -Lura
(0ry)(o,q orclyl(x- iso'f ='(tmil(1 ,r,fls'c)(x - t-5'\
4 * th.'7o0
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22. A0.500 g sample of naphthalene (c10H8) is burned in a bomb
calorimetercontaining 650 grams oiwater at an initial temperatureof
20'00'C' After thereaction, the finai temperature of the water
is26.4"C. The heat capacrty of the
calorimeter is 420 Ji"C. Using these data' calculate the heat of
combustion ofnaphthalene in kJ/mol-
tnp = (urro)(q. rarla*\&''{'4 = n'fiL*tcnl = (quTA(t,q'A =
L.t'.088 w
(rxn=-p/y,-w*'Hr Yffi23. considering the u"n
irtlTflc:lrl-roslfil*n tneffi
combination of AH and AS (in terms of negative or positive
signs)'AH AS++L
g-+k
a) Always spontaneous at all temperatures b) only spontaneous at
low temperatures
c) Only spontaneous at high temperatures'
1firy.Using the thermodynamic data,^determine if the following
reaction is spontaneous at
only higfo or only low L*poutor"s? (AS NO:210.7Jlmol*K, Nz:191'5
J/mol*K'oz:205.0 J/m:tTk__.
N2(g)+o2(g)*[-1805-E t 2No(e)
[1tu toi'6d A1 - i1ry lql tqq*dr-( tI 'tnot/r't'r'l.!= 4,41r
Slor*anmus ni high 1"
,\bh!. Consider 10.0 g of water placed in a freezer at -15oC.
What is the entopy change of'-*"sunoo"ding *f,"" the waier freezes?
For water AHruion:338J/g'
AS = |surr{
4tq, =e) %gf\AS= W
t68 r
r t[g tt$ = '33W{
