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Acid-Base Extractions and Isolation of Caffeine


Hello this lab report is for organic chemistry 1

I have posted the instructions below and I will be uploading some files below for the data please take a deep look at them because this lab report worth a lot of grade so please it needs to be done carefully

If any thing is missed regarding the lab report please let me know

This lab report will probably have a longer page count than normal (Intro and Discussion shouldn’t be particularly lengthy, but the other sections will take up extra space this week).

Acid-Base and Caffeine Extraction Postlab Report


Same Paragraph 1, Paragraph 2+hypothesis format. P1 is background info (definition of extraction, solubility to selectively extract compounds, properties of acidity/basicity to separate compounds during extraction, different types of extraction).

P2 starts with “In this experiment” (then a summary of what will be performed). Include the significant techniques, chemicals, and instruments and describe what the experiment involves. If you choose, P2 can be about the acid-base extraction and you can add a P3 about the caffeine extraction. Do what you need to do to stay organized and clear.

Hypotheses are tricky here, I suggest two (unless you can come up with a way to make it one statement). Some ideas to get you going:

For the acid-base extraction hypothesis, if you think the order of extraction could impact yield, you might predict which products will have higher or lower yields (think about possibilities for mass loss or retaining trace impurities). You might predict that all yields will be over 100% (and why) or that all yields will experience mass loss (and why).

For the caffeine hypothesis, you could focus on the melting point of the recrystallized product compared to the literature MP of caffeine (look it up, cite your source), and address purity. Or you could make a prediction about how the recovered mass will match up to the manufacturer specifications on the amount of caffeine per bag (support with reasoning). Just do your best to find the main purpose of each experiment and attempt to write a hypothesis to answer the question it’s asking. Choose an approach and give it a try (I’m not going to be super picky about these because this is a difficult hypothesis to write). The most important thing is to make the prediction testable and provide a supporting reason.


All compounds, tools, and equipment from both parts of the experiment. Include chemical safety notes.


Breaking this down into Part A, Part B (etc.) would be the best approach.


Photo of experiment notes in lab notebook (name, date, and experiment title at the top). Please don’t shrink the image too much – I need to be able to read it). We will discuss what should be in your notes during the Blackboard session.

Results and Calculations

Table 1: Solubility table from the data in your experiment notes (3 solids, 4 solvents). Same approach as last week (discussed in the Blackboard session for Module 4).

Table 2. All 3 solid compounds (benzoic acid, naphthalene, 4-chloroaniline), starting masses (assume mixture contained equal mass of each compound), mass of recovered compounds, and percent yield of each (theoretical yield here is the initial mass).

Table 3. Theoretical yield of caffeine (per manufacturer: 35mg per bag, and we used 2 bags), mass of recrystallized caffeine, percent yield of caffeine (recovered divided by theoretical).

Table 4. Experimental melting point of recrystallized caffeine, literature melting point of caffeine (cite a source).

NOTE: melting point is given as a single temperature in the experiment video. Experimental melting points should be recorded as a range, so let the temperature from the video be the top of the MP range and start it 1°C lower so you can report a range in Table 4.

Include the formula for percent yield (typed using the Word equation building feature).


Figures 1, 2, and 3. Line structure image of each compound (benzoic acid, naphthalene, 4-chloroaniline), and identify them in the captions by name and as the acid, base, or neutral compound. No hand drawings, and don’t photograph them from the lab manual – do a Google search to find the images and cite your source.

Figure 4. Line structure image of caffeine (Google search and cite your source).

Figure 5 BONUS (up to +5 points). Line structure of caffeine again, and identify at least 3 different functional groups by circling and naming them. This can be done on computer, tablet, or NEATLY hand drawn, photographed/scanned, and pasted into the report.

Make sure all tables and figures have a name/number and caption. Remember that it goes above a table, below for a figure.


Keep it simple. Each of the 3 compounds from the acid-base extraction should have its own brief paragraph that addresses the effectiveness of each extraction based on percent yield from Table 2. Were any of the extractions significantly more or less successful than the others? If percent yields were over 100% (can we end up with more than we started with?), suggest what impurities could be present in the products to result in the artificially high yield. How would you test for impurities? If mass loss occurred, suggest how/where mass may have been lost during the procedure.

The caffeine extraction should also have its own paragraph. Consider percent yields from Table 3 and melting point from Table 4, and comment on the success of the extraction and recrystallization of caffeine. What does the experimental melting point suggest about purity (compared to the literature melting point)? Did the tea bags yield the amount of caffeine per tea bag as reported by the manufacturer? If mass loss occurred, was it significant enough to suggest that the caffeine composition was below manufacturer specifications, or is it more likely that mass loss occurred during the procedure? Suggest specific ways mass may have been lost during the procedure (experiment error may be a factor here). What error took place during this experiment?

Remember to refer your reader to tables instead of repeating values. Numbers in the discussion should be part of the analysis. For example: An experimental melting point showed a 7°C range that began 15°C below the literature melting point (Table #), indicating presence of substantial impurities. Or one compound experienced 12% mass loss while another experienced 50% mass loss (Table #), suggesting that the first process was significantly more efficient than the second. Those numbers aren’t pulled directly from the tables; they are analyzing (comparing and drawing conclusions about) what was interesting from the data in the tables.

Postlab Questions

Questions are at the end of the lab manual handout. The formula for calculating the partition coefficient is on page 2 of the lab manual handout. The partition coefficient (distribution coefficient) question requires only simple algebra,


As always, at least 1 reference besides the lab manual (you’ll have multiple refs here since the figures need citations).

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