http://www.ck12.org Chapter 12. Stoichiometry
Lesson Summary
- Mole ratios can be derived from a balanced chemical equation. These ratios can then be used to determine the
amounts of each substance involved in a given chemical reaction. - Stoichiometry refers to calculations involving the relative amounts of various reactants and products that
participate in a chemical reaction.
Lesson Review Questions
- Aluminum reacts with oxygen to produce aluminum oxide as follows: 4Al + 3O 2 →2Al 2 O 3
(a) If you use 2.3 moles of Al, how many moles of Al 2 O 3 can you make?
(b) If you want 3.9 moles of Al 2 O 3 , how many moles of O 2 are needed? - In the presence of sulfuric acid, metallic iron forms iron(III) sulfate: 2Fe + 3H 2 SO 4 →Fe 2 (SO 4 ) 3 + 3H 2
(a) How many moles of hydrogen will be produced when you use 1.7 moles of iron?
(b) How much sulfuric acid is needed to produce 2.8 moles of iron(III) sulfate? - Write the mole ratios for reactants in terms of products for the following equation: 2 Mg + O 2 →2 MgO
- How many moles of each reactant are needed to produce 2.5 mol of aluminum oxide by the following reaction?
4 Al + 3 O 2 →2 Al 2 O 3 - How many moles of each reactant would be necessary to produce 2.6 mol of barium sulfate by the following
reaction? BaCl 2 + Na 2 SO 4 →BaSO 4 + 2NaCl
Further Reading/Supplementary Links
- Practice using mole ratios: http://www.wisc-online.com/Objects/ViewObject.aspx?ID=GCH7304
- Review of what stoichiometry is: http://www.chem4kids.com/files/react_stoichio.html
Points to Consider
- If you know how many moles of product a reaction yielded, can you find the mass of reactants used in the
initial reaction?