Honors Chemistry Name ______
Chapter 9: Stoichiometry, Limiting Reactant, Date _____/_____/_____ Period _____
and Percent Yield Calculations Worksheet IV
1. How much does 5.3 x 1019 molecules of the glass etching agent hydrofluoric acid weigh?
2. Nitrogen monoxide, NO, is an important signaling molecule in cells. It is also a major
component of smog, produced during the high temperature combustion reactions in engines,
according to the unbalanced equation N2 + O2 è NO. If an engine completely combusts all
the nitrogen in a 100. g sample of air that is 78.0% nitrogen by mass, with an excess of
oxygen provided by an oxidizing agent added to the gasoline, how many grams of nitrogen
monoxide are produced?
3. Ideal combustion, resulting in only carbon dioxide and water, rarely happens. In general, at
the very least, some carbon monoxide is also produced. The real combustion of methane is
more closely represented, then, by the unbalanced equation CH4 + O2 è H2O + CO2 + CO.
If 0.100 mol CH4 is allowed to react with 3.20 g O2, what is the limiting reagent, if any?
4. Using the data from problem three, how many grams of carbon monoxide will be produced?
5. Elemental zinc, Zn, reacts violently with elemental sulfur, S8. If 12.0 g of zinc react with
12.1 x 1024 atoms of sulfur, what is the limiting reagent, if any?
6. Using the data from problem five, how many moles of zinc sulfide, ZnS, are produced?
7. Using the data from problem five, how many grams of excess reactant remains after the
reaction has gone to completion?
8. What are two possible reasons for a reaction producing less product(s) than theoretically
calculated?
9. Iron (III) oxide, Fe2O3, reacts with elemental aluminum in a brilliant explosion, forming
elemental iron and aluminum oxide. If 15.0 g of Fe2O3 react with an excess of aluminum,
and careful analysis in a laboratory showed that 7.65 g of Al2O3 is produced, what is percent
yield of the reaction?
10. Aqueous solutions of sodium hypochlorite (NaOCl), best known as household bleach are
prepared by the reaction of NaOH with Cl2. How many grams of NaOCl would be produced
if 15.0g of NaOH reacts with 20.0 g of Cl2? What is the limiting reactant? How many
grams of NaOCl will be produced? How many grams of the excess reactant remains after
the reaction has gone to completion?
NaOH(aq) + Cl2(aq) è NaOCl(aq) + NaCl(aq) + H2O()