Unit 6 Lab - Temperature Effects ofEquilibrium
Photo Documentation
In order to earn full credit for the participation portion ofthis activity, you must submit at least 2 photos.Required photos are outlined in the procedure below.
Procedure
IMPORTANT SAFETY CONSIDERATIONS:
Avoid getting NaOH on your skin. Should you come in contact withthis chemical, immediately wash with water. Review all MSDSassociated with this lab.
Any broken or chipped glassware should be replaced.
Clean up spills immediately.
Create a buffer solution such that the pH=pKa, by adding halfthe amount of 1.00 M NaOH (prepared from the 6M NaOH provided inyour kit) needed to reach the endpoint of 10 mL of vinegar.
This can be performed by titrating a 15.0 mL aliquot of vinegarwith 1.00 M NaOH
Record the endpoint volume of NaOH
Add half the endpoint volume of NaOH to another 15.0 mL aliquotof vinegar into the test tube
The solution created in the previous step is a buffer solutionsuch that the pH=pKa
Place the test tube in the 600 mL beaker with enough warm tapwater to cover the solution in the test tube.
Place the thermometer in the test tube. Read the temperature andadjust the water until the temperature is near 30°C. (Takea photo)
When the temperature has stabilized record the temperature.Remove the thermometer and insert the pH probe and record thepH.
Insert the thermometer into the test tube and add ice to thebath to lower the temperature by 5°C. (Take aphoto)
Repeat steps 4 and 5 in 5°C increments until the solutionreaches 10°C.
Download and record all the data in the table linked here: DataAnalysis Table. You can also recreate the table and record the datain your lab notebook.
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Unit 6 Lab – Temperature Effects of Equilibrium
Data Analysis Table
pH | T (°C) | Ka | T(K) | ln(Ka) | 1/T (K-1) |
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Unit 6 Lab - Temperature Effects ofEquilibrium
Analysis
Reflect upon the question(s) below and record your response(s)in your lab notebook. Completion of this analysis will bebeneficial as you prepare for the post-lab quiz.
Your instructor will notify you if submission of this analysis isrequired.
Calculate the data for all the columns in the table youdownloaded/created during the procedure. Remember thepKa = pH for these buffer solutions.
Plot the data for the last two columns on the right. Plotln(Ka) on the y-axis and 1/T on the x-axis.
From the plot or from linear regression determine the slope ofthe best fit line.
From the slope determine the ∆H° for this reaction.
∆H°=_______________________________________________
Was the value of ∆H° what you expected (i.e.exothermic/endothermic)? Explain.
What is the effect on the equilibrium when the temperature ischanged? How is this related to ∆H°?
