- Given the reaction 3CH 4 + 4Fe 2 O 3 → 3CO 2 + 6H 2 O + 8Fe and atomic masses
of C, 12.0; H, 1.0; Fe, 55.8; and O, 16.0, what is the mass of CO 2 produced by the
reaction of 36.0 g of Fe 2 O 3?
- What is the basis of stoichiometry in respect to relative amounts of materials in
reactions?
- What are the major steps in doing a stoichiometric calculation?
- What is a limiting reactant?
- A solution of FeSO 4 was prepared by mixing 100 g of pure H 2 SO 4 with water and
putting it in contact with 50.0 g of iron metal. What reaction occurred? What masses
of reaction products were generated and what were the masses of reactants, if any,
left over? The atomic masses needed are H 1.0, Fe 55.8, S 32.0, and O 16.0.
- What is the difference between the stoichiometric yield and the measured yield in a
chemical reaction? How are they used to calculated percent yield?
- How are titrations and stoichometry related?
- A solid mineral sample consisting of calcium carbonate, CaCO 2 , and nonreactive
mineral matter weighing 0.485 g was stirred in some water to which 0.115 mol/L
standard hydrochloric acid, HCl, was added from a buret. The reaction was CaCO 3
- 2HCl → CaCl 2 + CO 2 + H 2 O. If 48.6 milliliters (0.0486 L) of HCl was required
to react with all the CaCO 3 in the sample, what was the percentage of CaCO 3 in the
sample given that the molar mass of CaCO 3 is 100 g/mol?
- A 250 mL sample of incinerator exhaust gas scrubber water contaminated with HCl
was titrated with 0.104 mol/L standard NaOH, of which 11.3 mL were required to
reach the end point. What was the molar concentration of HCl in the water sample?
- What is made by the Solvay process? What is the overall chemical reaction that
describes the Solvay process? What are the two major raw materials consumed and
what are two major species that are recycled through the process?
- What are major green aspects of the Solvay process? What are some aspects that are
less green?
- What is a major alternative to use of the Solvay process?
- A total of 38.6 g of A1Cl 3 contains (a) moles of the compound, whereas
217 g of methane, CH 4 , contains (b) moles of CH 4. Use 27.0,
35.5, 12.0, and 1.0 for the atomic masses of Al, Cl, C, and H, respectively.
- Why might you expect stoichiometric ratios to be used in industrial chemical reactions?
If one of two reactants used in an industrial process is much more expensive than
another, suggest why and in which way a stoichiometric ratio might not be used?
Also, suppose that one of two reactants is quite toxic whereas the other reactant is
Chap. 4. Chemical Reactions: Making Materials Safely 107
