Пламенная эмиссионная спектроскопия

Количественная идентификация металлов с помощью спектроскопа и пламени

Qualitative Analysis Advanced (University) 60 мин ~$15,00

Цель

Использовать спектроскоп для наблюдения и измерения длин волн эмиссионных линий различных ионов металлов в пламени.

Предпосылки

While simple flame tests show color, a spectroscope reveals the discrete emission lines responsible for those colors. Each element has a unique set of emission lines (an atomic fingerprint). This experiment bridges qualitative flame testing with the quantitative science of atomic emission spectroscopy, demonstrating Bohr's model of the atom and the origin of spectral lines.

Предупреждения по безопасности

  • Methanol is highly flammable and toxic — handle with extreme care
  • Do not look directly at the flame without the spectroscope
  • Keep all flammable materials away from the burner
  • Ensure good ventilation

Требуемые СИЗ

goggles gloves lab_coat

Материалы

  • Metal salt solutions (0.5M) (5 mL each)
    Na, Li, K, Cu, Sr, Ca, Ba chlorides
  • Hydrochloric acid (1M) (20 mL)
    Wire cleaning
  • Methanol (50 mL)
    For solution flame method
  • Distilled water (50 mL)

Оборудование

Handheld spectroscope or diffraction grating Bunsen burner Nichrome wire loops (7) Watch glasses (7) Spray bottle (for mist method)

Процедура

1

Set up the spectroscope by viewing a fluorescent light to calibrate and identify the mercury emission lines as reference.

5 мин
2

Clean a nichrome wire with HCl. Dip in sodium chloride solution and hold in the flame. View through the spectroscope and record the bright yellow emission at 589 nm.

7 мин
3

Repeat with lithium chloride. Record the bright red emission line near 671 nm.

7 мин
4

Repeat with potassium chloride. View through cobalt glass to filter sodium contamination. Record the violet emission near 766 nm.

7 мин
5

Test copper, strontium, calcium, and barium chlorides in sequence. For each, record all visible emission lines and their approximate wavelengths.

20 мин Clean wire between samples
6

Compile an emission spectrum chart showing each element's characteristic lines. Compare with published spectral data.

14 мин

Ожидаемые результаты

Each metal shows distinct spectral lines: Na at 589 nm (yellow doublet), Li at 671 nm (red), K at 766 nm (violet, visible through cobalt glass), Cu at 510–515 nm (green) and 325 nm, Sr at 461 nm (blue) and 606 nm (orange-red).

Уборка

Clean all nichrome wires with HCl. Dispose of metal salt solutions in inorganic waste. Rinse watch glasses.

Детали

Категория
Qualitative Analysis
Сложность
Advanced (University)
Продолжительность
60 мин
Прим. стоимость
$15,00
Шаги
6
Материалы
4

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Frequently Asked Questions

What is the objective of Пламенная эмиссионная спектроскопия?
Использовать спектроскоп для наблюдения и измерения длин волн эмиссионных линий различных ионов металлов в пламени.
How difficult is Пламенная эмиссионная спектроскопия?
This experiment is rated as Advanced (University). It takes approximately 60 minutes to complete.
What safety precautions are needed for Пламенная эмиссионная спектроскопия?
Key safety precautions include: Methanol is highly flammable and toxic — handle with extreme care; Do not look directly at the flame without the spectroscope; Keep all flammable materials away from the burner.
What materials are needed for Пламенная эмиссионная спектроскопия?
The main materials required are: Metal salt solutions (0.5M), Hydrochloric acid (1M), Methanol, Distilled water.
What results should I expect from Пламенная эмиссионная спектроскопия?
Each metal shows distinct spectral lines: Na at 589 nm (yellow doublet), Li at 671 nm (red), K at 766 nm (violet, visible through cobalt glass), Cu at 510–515 nm (green) and 325 nm, Sr at 461 nm (blue) and 606 nm (orange-red).