Practice Problems
Chapter 6-8: Chemical Reactions and Stoichiometry
1. Elemental analysis of butanedione gave the mass percent composition: C, 55.80%; H,
7.03%; O, 37.17%. The molar mass of butanedione is 86.09 g/mol. Determine the
molecular formula of butanedione.
2. Identify the type of chemical reaction for the chemical equation:
CH3CO2H (aq) + NaOH (aq)  NaCH3CO2 (aq) + H2O (aq)
a.
b.
c.
d.
Precipitation Reaction
Oxidation-Reduction Reaction
Combustion Reaction
Acid-Base Neutralization Reaction
3. Manganese (IV) oxide reacts with aluminum to form elemental manganese and aluminum
oxide. What mass of Al is required to completely react with 25.0 g of MnO2?
4. Cisplatin [Pt(NH3)2Cl2], a compound used in cancer treatment is prepared by reaction of
ammonia with potassium tetrachloroplatinate:
K2PtCl4 + 2NH3  2 KCl + Pt(NH3)2Cl2
a. How many grams of cisplatin are formed from 55.8 g of K2PtCl4?
b. The researcher isolated 30.0 g of cisplatin. What is the percent yield?
5. Balance the following reactions:
a. Fe + Cl2 → FeCl3
b. FeBr3 + H2SO4 → Fe2(SO4)3 + HBr
c. C4H6O3 + H2O→ C2H4O2
d. C2H4 + O2 → CO2 + H2O
e. C5H8O2 + NaH + HCl → C5H12O2 + NaCl
6. A student mixed two aqueous solutions of sodium sulfide and nickel (ii) chloride together
in a test tube. Write a molecular equation, total ionic equation, and net ionic equation.
7. Identify the oxidized and reduced reagent in each reaction:
a. 3 AgCl (aq) + Al (s)  3 Ag (s) + AlCl3 (aq)
b. Fe2O3 + 3 CO  2 Fe +3 CO2
c. 2 Mg + O2  2 MgO