SCH3U Final Lab Exam June 2014
In this investigation, you will combine your chemistry knowledge and laboratory skills to perform an investigation.
This experiment and the final written report are worth 10% of your final mark.

You will be put into groups of 2 and will choose one of the following topics. Only 5 groups per topic.

Synthesis and analysis of acetylsalicylic acid (ASA)

Determine the concentration of vinegar.

Prediction and analysis of the formation of a precipitate.

To be approved for your topic, you must complete the following:

Develop a detailed procedure ( including labeled diagrams of any laboratory equipment setup ).

Include a list of all required materials and chemicals (include quantities unless already specified).
It is strongly suggested that you use the Internet and other written references to develop your procedure. ** This initial phase will be evaluated for communication and thinking and inquiry .
Important Dates:
Procedure and Materials Due Date:
Laboratory Periods:
Final Report Due Date:
Wednesday May 28 th 2014
Monday, June 9 th - Tuesday June 10th
End of Class on Tuesday Jun. 10 th
NO EXCUSES & NO LATES ACCEPTED
WHAT IS DUE ON Jun 10 th at the end of class with no excuses and no lates accepted. o Research (typed, in your own words, referenced using APA and works cited) o Materials, RE-WRITTEN (modified for YOUR lab) o Labeled and referenced diagrams of equipment o Procedure (RE-WRITTEN for YOUR lab) o Observation table(s) (titled and neatly written) o Analysis (neatly written, proper units, organized)
Procedure Notes for the Synthesis and Analysis of Acetylsalicylic Acid
Acetylsalicylic Acid (ASA) is the active component in Aspirin. The benefits of ASA were first observed by the
Chinese in 500 B.C. ASA can be prepared by reacting salicylic acid with acetic anhydride using very SPECIFIC reaction conditions:
HC
7
H
5
O
3(s)
+ C
4
H
6
O
3(aq)
 HC
9
H
7
O
4(s)
+ HC
2
H
3
O
2(aq)
Analysis:

Determine the limiting reactant in this reaction (density of acetic acid anhydride is 1.0820 g/mL). Calculate the theoretical yield.

Calculate the percent yield of the ASA.

Perform an analysis on the purity of your final product. (ex. melting point determination on Day 2)

Identify the major sources of error and suggest how you could improve the percent yield.
Research:
1. Summarize how ASA works in the body (method of action).
2. Discuss the benefits and risks of daily “low dose” usage of ASA.

Procedure Notes for Determining the Concentration of a Sample of Vinegar
Vinegar contains approximately 5% acetic acid by volume. You will calculate the exact concentration of a sample of 10.0 mL of vinegar by performing a titration with a standard solution of sodium hydroxide. Based on the theoretical molar concentration of the vinegar, determine the concentration of sodium hydroxide needed for the titration and an appropriate indicator to use. This experiment must be performed three times to determine an average.
Analysis:

Determine the balanced chemical equation for this reaction

Determine the theoretical molar concentration of acetic acid. (mol/L) Density of vinegar is 1.01g/mL.

Calculate the concentration of the vinegar for each trial and the average concentration of the vinegar. (mol/L)

Find the % error of the concentration average.

Identify the major sources of error in this experiment and suggest how you could improve the experiment to obtain greater precision.
Research:
1. Outline how two different types of food grade vinegar can be made by fermentation.
2. Why is vinegar used to preserve pickles and other foods?
Procedure Notes for Determining the Yield of a Precipitate
Many reactions will form precipitates due to the low solubility of a newly formed product. In this lab you will react with . You will create two 0.1 mol/L solutions and will predict the precipitate formed. Based on the volume of each solution used in the reaction you will determine the theoretical yield of the precipitate and calculate the % yield for the reaction.
Analysis:

Determine the balanced chemical equation for this reaction

Determine the mass of each substance needed to make the solutions required.

Create the solutions required and complete the reaction.

Isolate and find the mass of the precipitate formed.

Calculate the theoretical yield of the precipitate, the actual yield of the precipitate and the % yield of the precipitate.

Identify the major sources of error in this experiment and suggest how you could improve the experiment to obtain greater precision.
Research:
1. Research the application of precipitation reactions in sewage treatment.
2. How does temperature affect the solubility of oxygen gas in water. How does this affect living organisms?