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Dry solid on porcelain plate:
Dry solid on porcelain plate:
Discuss:
Why is this necessary?
How would the melting range be effected if you were to skip this step?
Prepare a sample:
Prepare a sample:
open end facing down: press on solid to add sample to the capillary tube
open end facing up: drop capillary tube in a bounce tube on the counter top to pack sample on the bottom (closed end)
insert closed end into the MelTemp
MelTemp, capillaries, thermometer:
MelTemp, capillaries, thermometer:
Ready to go!
MelTemp analysis:
MelTemp analysis:
Monitor the thermometer and samples in the capillary tubes at the same time in the video below
MELTING RANGE = Record the temperatures on the thermometer in the video,
first when the solid begins to sweat and again when the entire solid melts.
You may need to watch the video several times!
Record the melting range for crude acetanilide (left lane).
Use the middle lane for your experimental (recrystallized) melting range in the lab report.
Don't forget! You may have made a decision earlier in the experiment where you were given instructions to subtract a certain number from that melting point.
The pure sample in the right lane is for your reference, not required in the report, but you will need to know that the "literature melting temperature" of pure acetanilide is 114.3 C.
It's important that the rate of temperature increase isn't set too high on the MelTemp!
It's important that the rate of temperature increase isn't set too high on the MelTemp!
Why could this be an issue?
3 spaces for capillary tubes – Left: crude; Middle: recrystallized; Right: pure
Video Sep 22, 13 14 15.movanother video of melting :)
another video of melting :)
...cuz we think it's cool!
The following data is for reference purposes only (do not include in report). 'Your' crude and recrystallized melting range should be recorded from the "MP Analysis" video above
Crude melting range: 108.5°C - 112.0 °C
Reference only - do not include in report: Pure acetanilide melting range: 109.5°C - 114.5°C (literature 114.3°C)
inside view: before
inside view: before
Left: crude, Right: pure
inside view: after
inside view: after
Left: crude, Right: pure
Lastly, compare your observed melting point ranges of the crude and recrystallized acetanilide to the literature value (is it higher or lower?).
Lastly, compare your observed melting point ranges of the crude and recrystallized acetanilide to the literature value (is it higher or lower?).
Discuss your results with your partner in terms of expected colligative properties.
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