Chapter 11 Review
232.3 g/mol
1) Novocain is C13H16N2O2. What is the molecular weight of novocain?
(Atomic weights: C = 12.01, O = 16.00, N = 14.01, H = 1.008).
334.4 g/mol
2) Penicillin G is C16H18N2O4S. What is the molecular weight of penicillin G?
(Atomic weights: C = 12.01, O = 16.00, N = 14.01, S = 32.06, H =
1.008).
135.1 g/mol
3) The controversial artificial sweetener saccharin has the molecular formula
C3H5O3NS. What is its molecular weight?
(Atomic weights: C = 12.01, H = 1.008, O = 16.00, N = 14.01, S
=32.06).
C2ClF5
4) A compound consists of 15.5% carbon, 23.0% chlorine and 61.5%
fluorine by mass. What is the empirical formula of the compound?
(Atomic weights: C = 12.01, Cl = 35.45, F = 19.00).
KMnO4
5) A dark green crystalline compound has the composition 24.7% K, 34.8%
Mn and 40.5% O. What is its empirical formula?
(Atomic weights: K = 39.10, Mn = 54.94, O = 16.00).
C3H4O2
6) Acrylic acid, used in the manufacture of acrylic plastics has the
composition 50.0% C, 5.6 % H and 44.0% O. What is its empirical
formula?
(Atomic weights: C = 12.01, H = 1.008, O = 16.00).
38.4% C
7) Hexachlorophene, a germicide, has the molecular formula C13H6Cl6O2.
What is the weight percent of carbon?
(Atomic weights: C = 12.01, H = 1.008, Cl = 35.45, O = 16.00).
17.4 % O
8) The mineral wulfenite is PbMoO4. To three significant figures, what is the
percent of oxygen?
(Atomic weights: Pb = 207.2, Mo = 95.9, O = 16.00).
12.1 % N
9) Novocain is C13H16N2O2. To three significant figures, what is the percent
of nitrogen?
(Atomic weights: C = 12.01, H = 1.008, N = 14.01, O = 16.00).
0.0413 mol
10) Butane, C4H10, is the fluid in disposable cigarette lighters. How many
moles are in 2.4 g of butane?
(Atomic weights: C = 12.01, H = 1.008).
2.38 mol
11) Up to 0.0100% of CuI may be added to table salt as a dietary source of
iodine. How many moles of CuI would be contained in 454 g (1 lb) of
such supplemented table salt?
(Atomic weights: Cu = 63.55, I = 126.90).
12.6 mol
12) A package of aluminum foil contains 12 ounces of aluminum ( 1 oz = 28.4
g). How many moles of aluminum atoms are in the package?
(Atomic weight: Al = 26.98).
30.8 g
13) What is the mass of zirconium in 0.338 mole of the mineral zircon,
ZrSiO4?
(Atomic weights: Zr = 91.22, O = 16.00, Si = 28.09).
2.97 e-3 g
(2.97 mg)
14) Methoxychlor, a garden insecticide, has the molecular formula
C16H15Cl3O2. What is the mass in milligrams of 8.6 x 10-6 moles of the
compound?
(Atomic weights: C = 12.01, H = 1.008, Cl = 35.45, O = 16.00).
483 g
15) An average 55 kg woman has 7.5 x 10-3 mole of hemoglobin in her blood.
The molecular weight of hemoglobin is 64,456. How many grams of
hemoglobin are in the blood?
C16H15Cl3O2
16) An insecticide has the weight percents C = 55.6%, H = 4.38%, Cl =
30.8% and O = 9.26%. The approximate molecular weight is 345. What
is the molecular formula?
(Atomic weights: C = 12.01, H = 1.008, Cl = 35.45, O = 16.00).
C14H18N2O5
17) Aspartame, an artificial sweetener, has the weight percents C = 57.1%, H
= 6.17%, N = 9.52% and O = 27.18%. The approximate molecular
weight is 295. What is the molecular formula
(Atomic weights: C = 12.01, H = 1.008, N = 14.01, O = 16.00).
C6H10O4
18) Adipic acid is used in the manufacture of nylon. The composition of this
acid is 49.3% C, 6.9% H and 43.8% O by mass. The approximate
molecular weight is 148 amu. What is the molecular formula?
(Atomic weights: C = 12.01, H = 1.008, O = 16.00).
MgSO4 ▪ 12H2O
19) An empty crucible has a mass of 12.770 grams. The crucible and hydrate
have a mass of 13.454 grams. After heating, the crucible and anhydrous
salt have a mass of 13.010 grams. What is the formula of this hydrate of
MgSO4 . ?H2O?
20) A 20g sample of a hydrate of nickel sulfate (NiSO 4) lost 9.63g of water
when heated. Determine the hydrate’s formula. Name it
21) A 16.59 g sample of hydrated sodium thiosulfate. The sample is heated
to drive off the
water. The dry sample has a mass of 10.59 g of sodium thiosulfate.
What is the formula for the hydrate? Name it.
22) A 35.64 g sample of hydrated barium bromide. The sample is heated to
drive off the water. The dry sample has a mass of 30.42 g of barium
bromide. What is the formula for the hydrate? Name it.
NiSO4 ▪ 8H2O
Na2S2O3 ▪ 5H2O
BaBr2 ▪ 3H2O