CHEM 1220 - Su19
LAB: CORRECTIONS, SUGGESTIONS, PRELAB & REPORT QUESTIONS
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- Exp. 1 (SOL - Variation of Solubility with Temperature and Solvent):
This is info is presently undergoing changes.
- Online Prelab: Due before the lab period. In Carmen or online at https://uglabs.cbc.osu.edu/
- Corrections, changes or hints to the lab manual:
- In all parts, when weighing your solute it is best to use a mass
closer to the lower end of the range given. Masses near the upper
end of the mass range sometimes cause problems with solubility, at
least in terms of how fast it will dissolve and how long it will take
you to finish lab.
- Part A (aqueous solution solubility), step 2:
- For oxalic acid the manual states to use 6.0-6.2 g.
Stick to a mass closer to something in the middle, 6.1.
- You will use this data to determine solubility and
mole fraction and for your graph.
- You will be given data for the solubility of potassium
dichromate, K2Cr2O7
in H2O in the pre-lab. You will use this to
do calculations for solubility and for the graph.
- Part B (mixed solvent solubility), step 9:
- For oxalic acid the manual states to use 6.0-6.2 g.
I suggest a mass close to 6.1 g.
- Do NOT attempt to insert a thermometer into a rubber sopper!
- The experiment is Part A (data from lab in water), Part B (date from lab
in 70:30 water/dioxane) and data for potassium dichromate from the pre-lab.
You will do calculations for these data and graph the data as three
separate data-sets on the same graph.
- Do NOT stir too vigorously. You don't want to ram the stirrer
through the bottom of the tube.
- Oxalic acid may dissolve the thermometer markings. These may be
renewed by scraping the thermometer with graphite from an ordinary pencil.
- In your reports, answer the Points to Consider such as "in which solvent
did the solute have a greate solubility and why"
- Exp 1 (SOL) - Help for Exp 1 (SOL)
- Exp 1 (SOL) - Example of Data Tables and Graphs Using MS Excel
- Waste Disposal:
- Each student should dispose of waste solutions in a beaker a your bench. This waste should
be disposed of in the beaker provided in the ORGANIC Waster Hood and record the
volume on the appropriate sheet. The TA will neutralize it and dispose of it properly.
- Post-lab on Carmen. Due before the next lab period just like a report.
- Exp. 3 (BAR - Determining the Kinetics for the Bleaching of Allura Red Dye):
- Online Prelab: Due before the lab period. In Carmen or online at https://uglabs.cbc.osu.edu/
- Under Construction
- The following is a link to an Excel file for an older version of a kinetics exp. You will be doing
something similiar in terms of the graphs. However, the example is a different exp. It follows
a product rather than a reactant, as you will be doing. In the end though, your Beer's Law graph
will look similar to my example (although with a very different slope, Beer's Law constant), as
will your first and second order plots. Remember, while my example shows a zero-order plot you
do NOT have to do this plot. However, there is a question about a zero-order plot and I think it
can be instructive to do it and look at it. If you do it, do NOT turn it in with the report.
Look at the last link as it gives an idea of what you're looking for in terms of the 1st and 2nd
order plots. Do both to linear fits (even though one shouldn't be linear). Look to see which one
gives lines which are more parallel. That's the order of the reaction with respect to the allura
red dye. The graph with the more parallel lines should also fit a linear fit better.
Exp 3 (DRL) - Using MS Excel
- Post-lab on Carmen. Due before the next lab period just like a report.
Exp. 4 (CLK - Exploring the Effect of Temperature on Reaction Rate):
- Online Prelab: Due before the lab period. In Carmen or online at https://uglabs.cbc.osu.edu/
- Corrections, changes or hints to the lab manual:
- Do your own work. Heat your own water.
- While heating solutions, keep them in the hood or point
tubes toward hood.
- Waste Disposal: Collect all solutions in a beaker at your desk.
Add the contents tothe metal salts waste beaker in the hood. Fill out
the waster disposal sheet. Dispose the 25-mL test tubes in the orange
disposable glassware bucket.
- Post-lab on Carmen. Due before the next lab period just like a report.
Exp. 5 (LCP - Equilibrium and Le Chatelier's Principle):
- Online Prelab: Due before the lab period. In Carmen or online at https://uglabs.cbc.osu.edu/
- Corrections, changes or hints to the lab manual:
- Waste Disposal: Sb(III), Co(II) in acid soln - neutralize
with 6 M NaOH to pH about 7 first (persistance of white ppt.),
and put into the Inorganic (metal salts) Waste Container. Collected
in beakers in the hood (students put waste in beakers and sign waste
disposal sheet).
- Exp 5 (LCP) - Help for Exp 5 (LCP)
- Post-lab on Carmen. Due before the next lab period just like a report.