Name ______________________________
Lab (Circle) W AM F AM F PM Date _______________
Partner______________________________
Pre-Lab Questions – Answers to these questions are generally found in the lab write up
Classify the following reactions as Combination, Decomposition, Single Replacement, or Double
Replacement.
1. What is an empirical formua?
2. Is it possible for the empirical and molecular formula to be the same? Explain your answer.
3. What is the percent composition of each element in magnesium acetate, Mg(C2H3O2)2?
4. What are the empirical formulas of each of the following compounds?
Compound
Empirical Formula
Na2C2O4
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P4O10
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C6C9N3
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C10H5Cl5
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Name ______________________________
Lab (Circle) W AM F AM F PM Date _______________
Partner______________________________
Post-Lab Questions – These are usually related to the techniques or calculations done during the lab.
1. When you placed the aluminum wire is the solution of the copper salt there were several things that
occurred that indicated a chemical reaction was taking place. Name at least three of therse
observations.
2. Why is it important that there be some unreacted aluminum wire at the end of the reaction.
3. A sample of 3.00 grams of an anhydrous cobalt bromide, CoBrn, is dissolved in water and treated with
magnesium ribbon. Magnesium is a more active metal than cobalt, and all the cobalt is precipitated as
solid cobalt metal. The cobalt is isolated and found to weigh 0.591 g. Find the empirical formula for this
bromide of cobalt.
4. If an experiment finds that the percent composition for a cobalt compound is 22.21% cobalt. The
actual percentage of the cobalt in the compound is 24.059 % Cobalt. Find the error in the percent cobalt
for this compound.