Chemistry 100
Clark College
Chapter 8 Homework SOLUTION
1. The reaction between hydrazine, N
H
, and hydrogen peroxide, H
O
, has been used as a
2
4
2
2
rocket fuel, given as the following balanced equation:
→ 2 HNO
N
H
+ 7 H
O
+ 8 H
O
2
4
2
2
3
2
According to this equation, how many grams of H
O
are required to completely react with
2
2
852 g of N
H
?
2
4
mol
7 mol H
O
34.0146 g
852 g N
H
x
x
2
2
x
= 6330 g H
O
2
4
2
2
32.045 g
1 mol N
H
mol
2
4
2. In dilute nitric acid, copper metal dissolves according to the following balanced equation:
→ Cu(NO
Cu + 4 HNO
)
+ 2 NO
+ 2 H
O
3
3
2
2
2
a) How many grams of nitric acid are required to dissolve 11.45 g of Cu?
mol
4 mol HNO
63.013 g
11.45 g Cu x
x
3
x
= 45.42 g HNO
3
63.546 g
1 mol Cu
mol
b) How many grams of NO
gas are formed?
2
mol
2 mol NO
46.006 g
2
11.45 g Cu x
x
x
= 16.58 g NO
2
63.546 g
1 mol Cu
mol
3. Iron metal reacts with oxygen gas to give iron (III) oxide.
a) Write a balanced equation for the reaction.
→ 2 Fe
4 Fe
+ 3 O
O
(s)
2(g)
2
3(s)
b) If an ordinary iron nail (assume that it is pure) has a mass of 2.68 g. What mass of iron
(III) oxide can be produced from the nail?
1 mol Fe
2 mol Fe
O
159.7 g Fe
O
2
3
2
3
2.68 g Fe x
x
x
= 3.83 g Fe
O
(rust!)
2
3
55.847 g Fe
4 mol Fe
1 mol
c) How many grams of oxygen are required for the reaction?
1 mol Fe
3 mol O
32.00 g O
2
2
2.68 g Fe x
x
x
= 1.20 g O
2
55.847 g Fe
4 mol Fe
1 mol
4. Nitrogen monoxide and hydrogen gas react to form NH
(ammonia) and water.
3
a) Write a balanced equation for the reaction.
→ 2 NH
2 NO + 5 H
+ 2 H
O
2
3
2
b) Starting with 86.3 g of nitrogen monoxide and 25.6 g of hydrogen, identify the limiting
reagent and the theoretical yield of ammonia.
2 mol NH
17.03 g NH
1 mol NO
3
3
NO: 86.3 g NO x
x
x
= 49.0 g NH
3
30.0 g NO
2 mol NO
1 mol NH
3
1 mol H
2 mol NH
17.03 g NH
2
3
3
H
: 25.6 g H
x
x
x
= 86.3 g NH
2
2
3
2.02 g H
5 mol H
1 mol NH
2
2
3
NO is the limiting reagent, 49.0 g of NH
will be produced
3
Chapter 8 Homework
Su07
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