Explain why the melting point depresses and broadens when a sample is impure .
How does the melting point of an impure substance compare to the melting point of a pure substance?
If your sample has impurities, would the melting point range be large or small. Explain why.
An impure 7.53g sample of (S)-ibuprofen was found in a container. The conclusion that the material was impure was based upon the observation of black colored particulate in the sample. The sample was recrystallized from a water methanol mix of solvents to yield 5.23g of material with a melting point of 76-79 degrees celsius. Answer the following questions: a) was the isolated material pure? explain. b) What was the percent recovery of (S)-ibuprofen from the original sample?
Explain why the melting point of pure hexane is lower than that of pure cyclohexane when the two compounds have nearly the same molecular weight.
Recrystallization: Percent error of melting point and
how impurities affect melting point:
Please explain both questions below:
(Part A) During a recrystallization experiment, the literature melting point of a compound is 105-107 °C. The melting point temperature you obtain from your recrystallized compound is 103-105 °C. Which of the following would be the proper way to set up the percent error of your mp? (a) (104/106)*100 (b) [(106-104)/106] *100 (c) (107/105)*100 (d) [(107-105)/107] *100 (Part B) For a recrystallization experiment...
8. a. Explain why the melting point of pure phthalic acid is higher than that of pure napthalene, when the two compounds have nearly the same molecular weight. b. Explain why the melting point of pure hexane is hgiher than that of pure cyclo-hexane, when the two compounds have nearly the same molecular weight. (Hint: reffer to structures)
ı. What is expected in measuring the melting point of a pure sample? 2. What is expected in measuring the melting point of an impure sample? 3. Look up the definition of the term Eutectic temperature. (Reference books available in the library or the chemistry lab, ask Mr. Funck to get them for you.) 4. What safety precautions should be observed in this laboratory'? s. Look up the melting points of the possible unknowns. Organic Chemistry with Vernier O Vernier...
Melting Point of p-dichlorobenzene 75.9 Melting Point of acetamide 53.2 degrees C Melting Point of solid mixture 53.8 degrees C Boiling Point of acetone 55.8 degrees C Boiling Point of ethyl alcohol 77.6 degrees C Boiling Point of acetone/ethyl alcohol mixture 72.7 What can you conclude about the melting points of pure and impure solids?
which of the following would you expect to have a higher melting
point? explain why
3. Which of the following would you expect to have the higher melting point? Explain why. (3 marks - 1 for the answer, 2 for the explanation) CI OH
The major reason why the melting point of your aspirin was below the reported value of 134 136 °C is? Select one: O a. It was contaminated with salicylic acid. O b. The salicylic acid was impure. O c. The equipment was not calibrated O d. It was contaminated with acetic acid O e. It was wet. O f. The literature is wrong.