Chemistry 111 โ Elementary Inorganic Chemistry
Morehouse College โ Problem Set #5
DUE: Friday, November 30, 2007
1. For each of the following compounds, indicate:
i. The molecular formula
ii. The molar mass
iii. The mass of substance in 50 mL of a 0.50 M solution of the compound.
a. Platinum(IV) chloride
b. Table salt
c. Hydrobromic acid
d. Acetic acid
e. Potassium hydroxide
f. Manganese(IV) oxide
6. Consider the following chemical reactions. For each, write a balanced chemical
equation then indicate, for each reaction, the mass of the underlined reagent
required to produce 1.12 g of the underlined product.
a. C
5
H
10
O
5(s)
+ O
2(g)
โ CO
2(g)
+ H
2
O
(g)
b. S
(s)
+ HNO
3(aq)
โ SO
2(g)
+ NO
(g)
+ H
2
O
(
l
)
c. Al
2
O
3(s)
+ NaOH
(aq)
+ H
2
O
(
l
)
โ Na[Al(OH)
4
]
(aq)
d. H
2
SO
4(aq)
+ Na
2
CO
3(aq)
โ Na
2
SO
4(aq)
+ H
2
O
(
l
)
+ CO
2(g)
e. H
2(g)
+ CO
(g)
โ C
8
H
18(
l
)
+ H
2
O
(
l
)
f. NaOCl
(aq)
+ NH
3(aq)
โ NaOH
(aq)
+ NCl
3(aq)
2. Calculate the mass percentages for each of the five elements in the following variety
of serpentine, a mineral with molecular formula H
4
MgFe
2
Si
2
O
9
.
3. Iron and oxygen form a series of compounds that have the following compositions by
mass:
Wustite Hematite Magnetite
% Iron --- --- ---
% Oxygen 21.39 28.99 26.62
a. What is the % composition of iron in each of the above oxides?
b. Determine the empirical formula for each of the oxides of iron described above.
4. A sample of copper oxide weighing 1.59 g yields 1.26 g of metallic copper when it is
reduced with hydrogen at high temperature and pressure.
a. What is the mass percent copper in the unknown copper oxide?
b. What is the empirical formula of the copper oxide?
c. If water is produced as a byproduct in the above reaction, write a balanced
chemical equation corresponding to this process.
d. Based on your answer to part (c), calculate the mass of the copper oxide
consumed when 2.5 L of hydrogen gas (initially at STP) are allowed to react
completely to afford copper metal and water.