Diffusionsratenvergleich (Graham'sches Gesetz)

Vergleich der Diffusionsraten von HCl- und NH₃-Gas

Gas Laws Intermediate (High School) 30 Min. ~$10,00

Ziel

Das Graham'sche Diffusionsgesetz überprüfen, indem die Geschwindigkeiten verglichen werden, mit denen HCl- und NH₃-Gas durch ein Glasrohr wandern.

Hintergrund

Graham's law states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass. When HCl (36.5 g/mol) and NH₃ (17 g/mol) diffuse toward each other in a tube, they form a white ring of NH₄Cl where they meet. The ring forms closer to the HCl end because NH₃ diffuses faster.

Sicherheitswarnungen

  • Concentrated HCl fumes are corrosive and irritating
  • Concentrated ammonia fumes are irritating
  • Perform this experiment in a fume hood or well-ventilated area
  • Do not inhale either gas directly

Erforderliche PSA

goggles gloves lab_coat

Materialien

  • Concentrated hydrochloric acid (5 mL)
    For HCl fumes
  • Concentrated ammonia solution (5 mL)
    For NH₃ fumes
  • Cotton wool (2 pieces)
    For soaking

Ausrüstung

Glass tube (1 m long, 2 cm diameter) Rubber stoppers (2) Ruler Retort stand and clamps Stopwatch

Durchführung

1

Clamp the glass tube horizontally on the retort stand.

3 Min.
2

In a fume hood, soak one cotton ball in concentrated HCl and another in concentrated ammonia.

2 Min. Fume hood — both gases are irritating
3

Simultaneously insert the HCl cotton ball into one end and the NH₃ cotton ball into the other end. Stopper both ends.

2 Min. Work quickly
4

Start the timer. Watch for a white ring of NH₄Cl to form where the two gases meet.

10 Min.
5

When the white ring appears, stop the timer. Measure the distance from each end to the ring.

3 Min.
6

Calculate the ratio of distances: d(NH₃)/d(HCl) should equal √(M(HCl)/M(NH₃)) = √(36.5/17) = 1.46.

5 Min.

Erwartete Ergebnisse

The white NH₄Cl ring should form approximately 60% of the way from the HCl end (40% from the NH₃ end), since NH₃ diffuses 1.46 times faster than HCl. The ratio d(NH₃)/d(HCl) should be approximately 1.4-1.5.

Aufräumen

Remove cotton balls and dispose in fume hood. Rinse the glass tube with water. Ventilate the area.

Details

Kategorie
Gas Laws
Schwierigkeit
Intermediate (High School)
Dauer
30 Min.
Geschätzte Kosten
$10,00
Schritte
6
Materialien
3

Weitere Experimente

Cartesischer Taucher 15 min Charles'sches Gesetz mit einem Luftballon 30 min CO₂ und Kalkwassertest 20 min Dampfdruck und Siedepunkt 45 min Gasstoichiometrie mit Magnesium 40 min Molvolumen eines Gases bei STP 35 min Verifikation des Boyle'schen Gesetzes 40 min Wasserstoffgasgewinnung 35 min

Frequently Asked Questions

What is the objective of Diffusionsratenvergleich (Graham'sches Gesetz)?
Das Graham'sche Diffusionsgesetz überprüfen, indem die Geschwindigkeiten verglichen werden, mit denen HCl- und NH₃-Gas durch ein Glasrohr wandern.
How difficult is Diffusionsratenvergleich (Graham'sches Gesetz)?
This experiment is rated as Intermediate (High School). It takes approximately 30 minutes to complete.
What safety precautions are needed for Diffusionsratenvergleich (Graham'sches Gesetz)?
Key safety precautions include: Concentrated HCl fumes are corrosive and irritating; Concentrated ammonia fumes are irritating; Perform this experiment in a fume hood or well-ventilated area.
What materials are needed for Diffusionsratenvergleich (Graham'sches Gesetz)?
The main materials required are: Concentrated hydrochloric acid, Concentrated ammonia solution, Cotton wool.
What results should I expect from Diffusionsratenvergleich (Graham'sches Gesetz)?
The white NH₄Cl ring should form approximately 60% of the way from the HCl end (40% from the NH₃ end), since NH₃ diffuses 1.46 times faster than HCl. The ratio d(NH₃)/d(HCl) should be approximately 1.4-1.5.