Chemistry 100
Clark College
Chapter 8 Homework
Follow the homework guidelines given in the syllabus! Show your work, use units and sig figs,
where appropriate.
1. The reaction between hydrazine, N2H4, and hydrogen peroxide, H2O2, has been used as a
rocket fuel, given as the following balanced equation:
N2H4 + 7 H2O2  2 HNO3 + 8 H2O
According to this equation, how many grams of H2O2 are required to completely react with
852 g of N2H4?
2. In dilute nitric acid, copper metal dissolves according to the following balanced equation:
Cu + 4 HNO3  Cu(NO3)2 + 2 NO2 + 2 H2O
a) How many grams of nitric acid are required to dissolve 11.45 g of Cu?
b) How many grams of NO2 gas are formed?
3. Iron metal reacts with oxygen gas to give iron (III) oxide.
a) Write a balanced equation for the reaction.
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?
c) How many grams of oxygen are required for the reaction?
4. Nitrogen monoxide and hydrogen gas react to form NH3 (ammonia) and water.
a) Write a balanced equation for the reaction.
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.
5. Solid iron (III) oxide reacts with carbon monoxide gas to form iron and carbon dioxide gas.
a) Write a balanced reaction (including phase labels) for this reaction.
b) Classify the reaction: is it single displacement or double displacement? Precipitation,
acid/base or redox?
c) If 187 gram of iron (III) oxide is allowed to react with 105.8 grams of carbon monoxide,
how much iron (in grams) can be generated?
6. Nitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at
high temperatures, as described by the following balanced equation.
2 NH3 (g) + 3 CuO (s)  N2 (g) + 3 Cu (s) + 3 H2O (g)
a) How many grams of N2 are formed when 18.1 g of NH3 are reacted with 90.4 g of CuO?
b) What starting material, if any is left over? How many grams of that material are left
over?
7. Chlorine dioxide is used as a disinfectant and bleaching agent. In water, it reacts to form
chloric acid (HClO3), according to the following balanced equation:
6 ClO2 + 3 H2O  5 HClO3 + HCl
a) If 142.0 g of ClO2 are mixed with 38.0 g of H2O, how many grams of chloric acid are
formed?
b) Which reactant is left over, and how much is left over?
8. In the previous problem, what it the percent yield for the reaction if 120.2 g of chloric acid is
actually produced?
Chapter 8 Homework
Su07
Page 1 of 2
Chemistry 100
Clark College
9. The deep blue Cu(NH3)4SO4 is made by the reaction of copper (II) sulfate with ammonia, as
described by the following reaction:
CuSO4(aq) + 4 NH3aq)  Cu(NH3)4SO4(aq)
a) If you use 10.0 g of ammonia and an excess of copper (II) sulfate, what is the theoretical
yield for the reaction?
b) If 18.6 g of Cu(NH3)4SO4 is isolated at the end of the reaction, what is the percent yield
for the reaction?
Chapter 8 Homework
Su07
Page 2 of 2