Flame Test Comparison Lab

Testing multiple metals to build a flame color reference chart

Flame Tests Intermediate (High School) 45 min ~$25.00

Objective

Perform flame tests on six different metal salts to create a reference chart of characteristic flame colors for qualitative analysis.

Background

This comprehensive flame test lab tests multiple metal salts side by side, building a reference chart that students can use for unknown identification. By comparing the flame colors of lithium, sodium, potassium, calcium, strontium, and copper directly, students develop the observational skills needed for qualitative chemical analysis.

Safety Warnings

  • Wear safety goggles at all times
  • Wear gloves when handling copper chloride
  • Handle HCl with care — avoid contact with skin
  • Keep hair tied back near open flames
  • Clean wire between each test to prevent cross-contamination

Required PPE

goggles gloves lab_coat

Materials

  • Lithium chloride (LiCl) (0.5 g)
  • Sodium chloride (NaCl) (0.5 g)
  • Potassium chloride (KCl) (0.5 g)
  • Calcium chloride (CaCl₂) (0.5 g)
  • Strontium chloride (SrCl₂) (0.5 g)
  • Copper(II) chloride (CuCl₂) (0.5 g)
    Toxic
  • Hydrochloric acid (HCl) (50 mL)
    1M concentration
  • Cobalt blue glass (1 piece)
    For potassium identification

Equipment

Bunsen burner Nichrome wire loop 6 labeled watch glasses Forceps Lab notebook

Procedure

1

Prepare six labeled watch glasses, each containing a small amount of one metal salt.

3 min Wear gloves for copper chloride
2

Clean the nichrome wire thoroughly by repeatedly dipping in HCl and heating until the flame shows no color.

3 min
3

Test lithium chloride first. Dip wire in HCl, then into the salt, and hold in the flame. Record the crimson-red color.

3 min
4

Clean the wire thoroughly. Test sodium chloride and record the bright yellow flame.

3 min
5

Clean the wire. Test potassium chloride. Observe with naked eye, then through cobalt blue glass. Record the lilac/violet color.

4 min
6

Clean the wire. Test calcium chloride and record the orange-red flame.

3 min
7

Clean the wire. Test strontium chloride and record the scarlet-red flame.

3 min
8

Clean the wire. Test copper(II) chloride and record the blue-green flame.

3 min
9

Create a complete reference chart organizing the metals by flame color from red through yellow to green and violet.

5 min

Expected Results

A complete flame color reference chart: Li (crimson-red), Sr (scarlet-red), Ca (orange-red), Na (yellow), Ba (yellow-green if tested), Cu (blue-green), K (lilac/violet through cobalt glass). Each color should be distinguishable from the others.

Cleanup

Clean the wire with HCl. Dispose of copper waste in the heavy metal waste container. Dispose of remaining salts per lab protocol. Clean and dry all watch glasses.

Details

Category
Flame Tests
Difficulty
Intermediate (High School)
Duration
45 min
Est. Cost
$25.00
Steps
9
Materials
8

More Experiments

Barium Flame Test 20 min Calcium Flame Test 15 min Copper Flame Test 15 min Lithium Flame Test 15 min Potassium Flame Test 20 min Sodium Flame Test 15 min Strontium Flame Test 15 min

Frequently Asked Questions

What is the objective of Flame Test Comparison Lab?
Perform flame tests on six different metal salts to create a reference chart of characteristic flame colors for qualitative analysis.
How difficult is Flame Test Comparison Lab?
This experiment is rated as Intermediate (High School). It takes approximately 45 minutes to complete.
What safety precautions are needed for Flame Test Comparison Lab?
Key safety precautions include: Wear safety goggles at all times; Wear gloves when handling copper chloride; Handle HCl with care — avoid contact with skin.
What materials are needed for Flame Test Comparison Lab?
The main materials required are: Lithium chloride (LiCl), Sodium chloride (NaCl), Potassium chloride (KCl), Calcium chloride (CaCl₂), Strontium chloride (SrCl₂).
What results should I expect from Flame Test Comparison Lab?
A complete flame color reference chart: Li (crimson-red), Sr (scarlet-red), Ca (orange-red), Na (yellow), Ba (yellow-green if tested), Cu (blue-green), K (lilac/violet through cobalt glass). Each color should be distinguishable from the others.