Flame Tests and Flame Emission Spectroscopy

Introduction

• Objective: Learn to use flame tests to identify five metal ions and understand flame emission spectroscopy.
• Audience: Triple chemistry students.

Flame Tests

• Purpose: Identify metal ions in unknown compounds.
• Procedure:
  1. Place a small amount of chemical on a wire mounted in a handle.
  2. Insert end into a blue Bunsen burner flame.
  3. Observe flame color to determine metal ion.
• Key Flame Colors to Memorize:
  • Lithium Ion: Crimson
  • Sodium Ion: Yellow
  • Potassium Ion: Lilac
  • Calcium Ion: Orange-red
  • Copper Ion: Green
• Limitations of Flame Tests:
  • Difficult to distinguish colors at low metal concentrations.
  • Mixtures of metal ions can mask colors, e.g., sodium's intense yellow.

Flame Emission Spectroscopy

• Process:
  • Place metal ion solution into a flame.
  • Light emitted passes into a spectroscope.
  • Spectroscope converts light into a line spectrum.
• Key Points:
  • Line positions are specific to metal ions, aiding identification.
  • Can determine metal ion concentration; higher concentration results in more intense lines.
• Advantages of Instrumental Methods:
  1. Rapid: Analyzes samples faster than flame tests.
  2. Sensitive: Effective even on tiny metal samples.
  3. Accurate: More accurate identification than flame tests.

Additional Resources

• For more practice questions on these topics, refer to the provided revision workbook.