Kristallisation von Salol (Phenylsalicylat)

Beobachtung von Kristallwachstum unter dem Mikroskop in Echtzeit

Crystallization Intermediate (High School) 30 Min. ~$10,00

Ziel

Das Echtzeit-Wachstum von Salol-Kristallen unter dem Mikroskop beobachten und dabei Keimbildung, Kristallwachstumsraten und den Einfluss der Temperatur auf die Kristallmorphologie untersuchen.

Hintergrund

Salol (phenyl salicylate) has a melting point of 43°C, making it perfect for observing crystallization under a microscope in real time. It can be melted on a microscope slide and watched as it crystallizes, with the crystal fronts growing visibly. Supercooling is easily demonstrated.

Sicherheitswarnungen

  • Salol can irritate skin — wash hands after handling
  • Handle microscope slides carefully — breakage risk
  • Do not overheat salol (decomposes above 70°C)

Erforderliche PSA

goggles

Materialien

  • Salol (phenyl salicylate) (2 g)
    Melting point 43°C
  • Microscope slides (3)
  • Cover slips (3)

Ausrüstung

Microscope (at least 40x) Hot plate or warm water bath Tweezers Timer

Durchführung

1

Place a small amount of salol on a microscope slide. Warm gently on the hot plate until the salol melts (43°C). Place a cover slip on top.

5 Min. Do not overheat — decomposes above 70°C
2

Place the slide on the microscope stage. Focus at low magnification (40x). Allow to cool.

3 Min.
3

Watch for nucleation points — small bright spots where crystal growth begins.

5 Min.
4

Observe the crystal growth fronts expanding across the field of view. Time the growth rate.

5 Min.
5

Touch a cold metal object to one edge of the slide to create a temperature gradient. Observe how crystal morphology changes with cooling rate.

5 Min.
6

Draw or photograph the crystal patterns. Note the needle-like or fan-shaped morphology.

5 Min.

Erwartete Ergebnisse

Needle-like or fan-shaped crystal fronts should be visible growing across the field of view in real time. Faster cooling produces finer needles; slower cooling produces larger, more regular crystals. Supercooling may be observed (liquid persists below 43°C until nucleation occurs).

Aufräumen

Allow slides to cool completely. Scrape off salol and dispose in solid waste. Clean slides with ethanol.

Details

Kategorie
Crystallization
Schwierigkeit
Intermediate (High School)
Dauer
30 Min.
Geschätzte Kosten
$10,00
Schritte
6
Materialien
3

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Frequently Asked Questions

What is the objective of Kristallisation von Salol (Phenylsalicylat)?
Das Echtzeit-Wachstum von Salol-Kristallen unter dem Mikroskop beobachten und dabei Keimbildung, Kristallwachstumsraten und den Einfluss der Temperatur auf die Kristallmorphologie untersuchen.
How difficult is Kristallisation von Salol (Phenylsalicylat)?
This experiment is rated as Intermediate (High School). It takes approximately 30 minutes to complete.
What safety precautions are needed for Kristallisation von Salol (Phenylsalicylat)?
Key safety precautions include: Salol can irritate skin — wash hands after handling; Handle microscope slides carefully — breakage risk; Do not overheat salol (decomposes above 70°C).
What materials are needed for Kristallisation von Salol (Phenylsalicylat)?
The main materials required are: Salol (phenyl salicylate), Microscope slides, Cover slips.
What results should I expect from Kristallisation von Salol (Phenylsalicylat)?
Needle-like or fan-shaped crystal fronts should be visible growing across the field of view in real time. Faster cooling produces finer needles; slower cooling produces larger, more regular crystals. Supercooling may be observed (liquid persists below 43°C until nucleation occurs).