Test de Flamme au Lithium

Identification du lithium par sa flamme rouge cramoisi

Flame Tests Beginner (Middle School) 15 min ~$8,00

Objectif

Observer la couleur rouge cramoisi caractéristique de la flamme produite par les ions lithium, et la comparer aux tests de flamme des autres métaux alcalins.

Contexte

Lithium produces a distinctive crimson-red flame when heated. The emission occurs primarily at 670.8 nm as the excited 2s electron returns to the ground state. Lithium compounds were historically used to produce red colors in fireworks before the introduction of strontium-based alternatives.

Avertissements de sécurité

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

EPI requis

goggles lab_coat

Matériaux

  • Lithium chloride (LiCl) (1 g)
  • Hydrochloric acid (HCl) (10 mL)
    1M concentration
  • Distilled water (50 mL)
    For cleaning

Équipement

Bunsen burner Nichrome wire loop Watch glass Forceps

Procédure

1

Clean the nichrome wire by dipping in HCl and heating until no color is visible in the flame.

2 min
2

Place a small amount of lithium chloride on the watch glass.

1 min
3

Dip the clean wire into HCl, then touch it to the lithium chloride sample.

1 min
4

Hold the wire in the Bunsen burner flame and observe the characteristic crimson-red color.

2 min Keep face away from flame
5

Record observations and compare with the sodium flame test if already performed.

1 min

Résultats attendus

A bright crimson-red flame should appear. The color is distinct from the red produced by strontium (which is more scarlet) and potassium (which is lilac/violet).

Nettoyage

Clean the wire loop with HCl. Dispose of chemicals per lab protocol.

Détails

Catégorie
Flame Tests
Difficulté
Beginner (Middle School)
Durée
15 min
Coût estimé
$8,00
Étapes
5
Matériaux
3

Plus d'expériences

Laboratoire de Comparaison des Tests de Flamme 45 min Test de Flamme au Baryum 20 min Test de Flamme au Calcium 15 min Test de Flamme au Cuivre 15 min Test de Flamme au Potassium 20 min Test de Flamme au Sodium 15 min Test de Flamme au Strontium 15 min

Frequently Asked Questions

What is the objective of Test de Flamme au Lithium?
Observer la couleur rouge cramoisi caractéristique de la flamme produite par les ions lithium, et la comparer aux tests de flamme des autres métaux alcalins.
How difficult is Test de Flamme au Lithium?
This experiment is rated as Beginner (Middle School). It takes approximately 15 minutes to complete.
What safety precautions are needed for Test de Flamme au Lithium?
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 Test de Flamme au Lithium?
The main materials required are: Lithium chloride (LiCl), Hydrochloric acid (HCl), Distilled water.
What results should I expect from Test de Flamme au Lithium?
A bright crimson-red flame should appear. The color is distinct from the red produced by strontium (which is more scarlet) and potassium (which is lilac/violet).