Chemistry 11 (SCH3U)
Quantities in Chemical Reactions
Empirical and Molecular Formula Problems
Name: ____________________
All of the questions below will be included as a part of your thinking and inquiry mark
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Instructions
Remember to show all of your work and don’t forget about significant digits.
1.
Determine the empirical formula of a compound made up of 52.51% chlorine and 47.48% sulfur. (2 Marks)
2.
Compound X contains 69.9% carbon, 6.86% hydrogen, and 23.3% oxygen. Determine the empirical formula
of compound X. (3 Marks)
3.
Olive oil is used widely in cooking. Oleic acid, a component of olive oil, contains 76.54% carbon, 12.13%
hydrogen and 11.33% oxygen by mass. What is the empirical formula of oleic acid? (3 Marks)
4.
Oxalic acid has the empirical formula CHO2. Its molar mass is 90g/mol. What is the molecular formula of
oxalic acid? (3 Marks)
5.
The empirical formula of codeine is C18H21NO3. If the molar mass of codeine is 299g/mol, what is its
molecular formula? (3 Marks)
6.
A compound has the formula C6xH5xOx, where x is a whole number. Its molar mass is 186g/mol; what is its
molecular formula? (3 Marks)