Kaliumflammtest

Kalium an seiner flieder-/violetten Flamme erkennen

Flame Tests Beginner (Middle School) 20 Min. ~$6,00

Ziel

Die flieder-/violette Flammenfarbe von Kaliumionen beobachten und lernen, mit kobaltblauem Glas die Verunreinigung durch Natrium zu unterscheiden.

Hintergrund

Potassium produces a pale lilac or violet flame when heated. The emission occurs at 766.5 nm and 769.9 nm (near-infrared/deep red doublet). Because the flame is quite faint and easily overwhelmed by sodium's intense yellow, cobalt blue glass is used as a filter to block sodium emission and reveal potassium's true color.

Sicherheitswarnungen

  • Wear safety goggles at all times
  • Keep hair tied back near open flames
  • Handle HCl with care

Erforderliche PSA

goggles lab_coat

Materialien

  • Potassium chloride (KCl) (1 g)
  • Hydrochloric acid (HCl) (10 mL)
    1M concentration
  • Cobalt blue glass (1 piece)
    For filtering sodium light

Ausrüstung

Bunsen burner Nichrome wire loop Watch glass Forceps

Durchführung

1

Clean the nichrome wire thoroughly by dipping in HCl and heating.

2 Min.
2

Place potassium chloride on the watch glass and collect a sample on the clean wire.

1 Min.
3

Hold the sample in the Bunsen burner flame. Observe with the naked eye first.

2 Min.
4

Now observe the flame through cobalt blue glass to filter out any sodium contamination.

2 Min.
5

Record the difference in appearance with and without the cobalt blue glass filter.

2 Min.

Erwartete Ergebnisse

Without the filter, you may see a faint lilac color possibly masked by yellow from sodium impurities. Through the cobalt blue glass, a clear violet/lilac flame should be visible as the glass absorbs the yellow sodium emission.

Aufräumen

Clean the wire loop with HCl. Return cobalt blue glass to storage.

Details

Kategorie
Flame Tests
Schwierigkeit
Beginner (Middle School)
Dauer
20 Min.
Geschätzte Kosten
$6,00
Schritte
5
Materialien
3

Weitere Experimente

Bariumflammtest 20 min Calciumflammtest 15 min Kupferflammtest 15 min Lithiumflammtest 15 min Natriumflammtest 15 min Strontiumflammtest 15 min Vergleichslabor für Flammentests 45 min

Frequently Asked Questions

What is the objective of Kaliumflammtest?
Die flieder-/violette Flammenfarbe von Kaliumionen beobachten und lernen, mit kobaltblauem Glas die Verunreinigung durch Natrium zu unterscheiden.
How difficult is Kaliumflammtest?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for Kaliumflammtest?
Key safety precautions include: Wear safety goggles at all times; Keep hair tied back near open flames; Handle HCl with care.
What materials are needed for Kaliumflammtest?
The main materials required are: Potassium chloride (KCl), Hydrochloric acid (HCl), Cobalt blue glass.
What results should I expect from Kaliumflammtest?
Without the filter, you may see a faint lilac color possibly masked by yellow from sodium impurities. Through the cobalt blue glass, a clear violet/lilac flame should be visible as the glass absorbs the yellow sodium emission.