Ed.
SampleProblems
1. Oneoxideof nitrogenis foundto havean orygen-to-nitrogen
massratio of 1.142:l (thatis,
| .1429of oxygenfor every 1.0009of nitrogen). Which of the following oxygen-to-nitrogenmass
ratios arepossiblefordifferent oxidesof nitrogen?
+q
,A
[ (a)0.57r:r
l--/
l,lw"l
._+"
0,51t
, ,I
:
I,ooot I
=D , 9 8
f. l.{a'. t
L
(d)>dau
(fi.r*t'r
L,265',
l,
t4?- :. t
I
z ,5;ac: I
=Z
l, llA',
--
-,
A,
I
2. For each of the numbered speciesbelow that is a neutral atonr, write its isotopic notation. Which
#2 + t
ofthese species are isotopes'l
?
# orotons
# neutrons
# electrons
Isotopic
Notation
#l
r #2)
#3
#4
C_*s
)
t6
-0
19
2l
l8
22
26
22
20
20
20
IE
t8
Nrrf
Yr*
Np{
P'ar-{rr-J
Llg
r-t }
L'L
28
20
qb/
zc LA
3. The two naturallyoccurringisotopesof rubidium arerubidium-85,with an atomicmassof
84.9ll79arnu;andrubidium-87,with an atomicmassof 86.90919amu.Whatarethe percent
naturalabundances
of theseisotopes?
8E,+1
b 4 . n l l " q ( x ) f f i b . 1 o trqf r-x):
8 , , tq, r r ' t t y + b b , q o q t q
*b,1Dt[$x ;- #s'q1
=
t.4?qll
I .aq?4x
\ flb ^95 = 7Z,of
i eb -b) ? 21,4f
2o
40
x -- D.1LDS
I -x = a, Laqg
4. Fill in the blanks.
(a) The symbol and atomic number of the heaviest alkaline earth metal are
F**dbB.
(b) The symbol,andatomicnumberof the lightestmetalloid in Group 5A (15) are
and
F\g
2V
(c) The symbol and atomic mass ofthe halogen in Period 4 are
Br
(d) The synbol and atornic number of the heaviest noble gas are
?n
" 11..
10
8lo
and
and
l4
I t
5. Which of the following arepure substances
andqihich aremixtures? If th€y se mixture are
they homogeneous or hete,rogeneous.
(a) helium gas used to fill a balloon
q s-W"fu,,*lc"c. - e,{*rttl*-Ei
P,r*<
(b) thejuice squeezedfrom a lemon HA{€{t
(c) a premiumred wine
%-r1-a- f\4
r- f
VlOrr"tllEt*V-Vt
X }z-.-r-.c-
fflL
<-
r',-Lr X *t*r
(d) Italiansaladdressing
rYtixh*t L
@S
6. Give the nameor the molecularformula for the following compounds.
Name
Formula
Silicon tetrachloride
5, C\-k
(a)
(b)
4i^"<itr-
J,i;oJ^'r.e,
y
IzOs
(c)
NaH=.o4
Sodium hydrogen sulfate
(d)
CArpnni *t"r (a)
(Ct vorr-rp .-t9)
re*r"'a"$<
0.or-ta{rqJ"o'ft
Cr(NO3)2'9I{2O
(e)
llc-" {-fa D.
Acetic acid
(0
Cl^[or or-r.4, a-d"A
G)
HCIO2
(nir+n)"
G *ot
Ammoniumdichromate
(h)
byufa-n a
CH3CH2CH2CH3
7. Calculate the molecular mass of magnesium dihy&ogen phosphate.
r\n ( t\,-?ol,
6
NY
F|
2,4. Vl
LI* \.oob
7
?
Z*
0
U
I
rt
7o,71
S * Ib'oO
-Lr\.
,VI
\,
oVZ
bt. qq
\aa
lq, Lg
a'..rrA