REVIEW: MOLES, % COMPOSITION, EMPIRICAL AND MOLECULAR FORMULA'
CHEMISTRY 1406
`i
1. Calculate the number of grams in 0.02 4 mol of tin I i • r de a tooth decay preventative
D,b2; y mol Sn Fa t5t,-~~
I mA4
2. Calculate the molar mass of potassium hydrogen tartrate. (KHC411406).
3. How many moles of gold, Au, are in 3.60 X 10-10 g of gold?
3.
1 ►Ka
19-1 Cr
1.83 C5~
4. How many moles of silver are in 3.01 X 1023 atoms of silver.
x~ O~ 3c~anv~ I ~n,oQ 1 2 ~~ I 1~t~ -= "p , S ~
'.oax~oz3 ~
5. Calculate the mass of 1.05 X 1018 atoms of mercury.
b •02 x l0 ",,_ t mt.aQ
6. Calculate the mass of 1 atom of neon.
Map
~zo ~(Sn)
10- ZS
7. Which contains more particles: 1 mole of sulfur atoms or1 mole of magnesium oxide compounds?
5&ffyL0-- — bau~\—
8. What is the molar mass of SrCl2.6H2O ?
4fl,,,Q
9. What is the mass of 6.25 mol of copper (II) nitrate.
10. Ibuprofen, C13111802, is the active ingredient in many nonprescription pain relievers.
A.) Calculate ibuprofens' molar mass: z0(p ,31~.1M0
Q
B.) If the tablets in the bottle contain a total of 33g of ibuprofen, how many moles of ibuprofen are in
the bottle?
33~
2dc~ , 3(j
) b, I~ rn~
C.) How many molecules of ibuprofen are in the bottle
0 , [ ~,
/ ~.0a ~ I 6Z3--~
q. 6 L4 x ► pZZm
\
11. A large neon sign is to be filled with a mixture of gases, including 8.575g neon. What number of
moles is this?
(~A-O
'S,S-9s~N~-,-
20, Igo
12. How many molecules are in 342.34 g of C12H22011?
3
xloZ
13. Calculate the percent carbon and percent sulfur in carbon disulfide: (CS2)
%C=
-7~,, 13
Dios=
(" L+,lz x X60 = ~y, as
°lo
-7(,,l3
S
14. Calculate the percent by mass of each of the following in limestone, CaCO3.
%Ca =
40.08
loo' o9 _ t}d,(~~
%CO3 = (Q o ,o I
loo C)9
Flo Lal
=59,95(Q = 59,91,% 3
dv~
~
P
15. Calculate the % water in magnesium sulfate
e. (MgSO4 i~ih20)
D
'-at X1 20 Pat )
c2 MO, y7
16. Calculate the % nitrate, (NO3) in aluminum nitrate, AI(NO3)3-
3
13, 0
17. Find the empirical formula c a compound that contains 53.70% iron and 46,30% sulfur.
I Ynn~
= b.9Gi5M&A = I x a
Fe a 3
5-3 ,-7 C) Fr. C55.8
5 '~
. 1, 44 L4IM o l = 1, 5 -Za
3Z, o(Dc~
6) .9Cp Is18. Analysis of a compound indicates that it contains 1.04 g K, 0.70 g Cr, an
Find the
empirical formula of this compound.
o , ba('s98 P = 119 8
j ~ 0Z+
K~
d.o134~i
b o~34to i ~ _ I
~, 1U ICv
_
= 3,99
0 , Ko-t D
) z- 0,05 r. ~
(ro .o
19. Although the min*Rl ilmenite c6ffi-ails more iron than titanium, the ore is usually mined and
processed for titanium, a strong, light, and flexible metal. A sample of ilmenite is found to contain
5.41 g iron, 4.64 g ti
um, and 4.65~ gg oxygen. Determine the em.' ' al fnrr~ lla.
D~b9~a(n(P
5,4l ~~
I
J =
►'`~?
I
4. (0 4 5'T'
4~ sts
3 9 S ~~ma.4
~~
20. Calculate the empirical formula for a compound whose analysis is 74.97% Al and 25.03 % C.
1
-74,9-12!2- Al"1~=
, ~ -7 & ,a y =
Rs~ zAa.6F~-lo
aSo3 L C.
1.333 X, 3 = 4
A \ 1j C3
~_l.2,o L
21. The percent composition of an unknown compound is found to be 38.43 % Mn, 16.80 % C, and
44.77 % O. Determine the compounds empirical formula.
38.x-35 Mn ~ ~ ~ = b,~g44 n~ = 1
1' 2-1 Z5
3
.
1 .015 J — o,c,a945
J
9 e~ 9
1,
1
Mn
I
22. A colorless liquid composed of 46.68% N, and 53.32%0 has a
the molecular formula?
i. •
- -, ,ss of 60.01 g ol. What is
I r-,DP ) = 3,3319 05 -
14
33 a S23. The molar mass of a compound is 92 g/mol. Analysis of a sample of the compound indicates that it
contains 0.606 g trogei}, and 1.39 g oxygen. Find the empirical and, -molar formula.
0 ,(~oc~ ~ NJ
—j~ oI 1 = o ,t3a5
,o
b F(.
~
y~ .o
b,o 4 3 A 5
24. The hydrocarbon propylene has a molar mass of 42.00 g and contains 85.7% C and 14.3%
Determine the empirical and molecular formula.
E:1:—
MF
CH
-
l~_oI
14,3 N ~ J
-1,13511;11
25. Fructose is a very sweet natural sugar that is present in honey, fruits, and fruit juices. It has a molar
mass of 180.1 g/mol and a composition of 40% C, 6.7% H, and 53.3% O. Calculate the empirical and
molecular formula of fructose.
401 C
L-t=~C0a o
12.01
MF
J
5-3,3 0
:-~
41 -2- 0~
~- —)
~
3,330 S-5-
3,331aS =
- 5'1~ -1 _~
3~) . 0 3