振動するブリッグス-ラウシャー反応

無色・琥珀色・深青色を繰り返す化学時計

Classroom Demonstrations Advanced (University) 40 分 ~$20.00

目的

三つの異なる色の状態を繰り返す化学振動反応を観察し、非線形化学動力学を実証する。

背景

The Briggs-Rauscher reaction is one of the most visually stunning demonstrations of oscillating chemical kinetics. Three solutions are mixed, and the resulting solution spontaneously cycles between colorless, amber, and deep blue states for several minutes. The oscillations occur because two competing reaction pathways alternately dominate: a radical pathway (producing I₂, which reacts with starch to form the blue color) and a non-radical pathway (consuming I₂, clearing the blue).

安全上の警告

  • 30% H₂O₂ causes burns — handle with extreme care
  • H₂SO₄ is corrosive
  • KIO₃ is an oxidizer
  • Wear face shield during mixing step
  • Do not lean over the reaction vessel

必要なPPE

goggles gloves lab_coat

材料

  • Potassium iodate (KIO₃) (4.3 g)
    Solution A component
  • Malonic acid (CH₂(COOH)₂) (1.6 g)
    Solution B component
  • Manganese(II) sulfate (MnSO₄) (0.4 g)
    Solution B catalyst
  • Starch solution (1%) (5 mL)
    Solution B indicator
  • Hydrogen peroxide (30%) (50 mL)
    Solution C
  • Sulfuric acid (1M H₂SO₄) (20 mL)
    Solution A acidification
  • Distilled water (500 mL)

器具

Beakers (500 mL, 3 for solutions + 1 for mixing) Magnetic stirrer and stir bar Graduated cylinders White background paper

手順

1

Prepare Solution A: Dissolve 4.3 g KIO₃ in 100 mL warm water. Add 20 mL of 1M H₂SO₄.

5 分 Handle acid carefully
2

Prepare Solution B: Dissolve 1.6 g malonic acid and 0.4 g MnSO₄ in 100 mL water. Add 5 mL of 1% starch solution.

5 分
3

Prepare Solution C: Dilute 50 mL of 30% H₂O₂ to 100 mL with water.

3 分 30% H₂O₂ is corrosive
4

Set the magnetic stirrer to moderate speed. Pour all three solutions simultaneously into the large beaker on the stirrer.

2 分 Step back after mixing
5

Observe: the solution cycles colorless → amber → deep blue → colorless, repeating for 5–15 minutes. Time the oscillation period.

15 分
6

Record the number of oscillations and the period of each cycle. Note how the period changes over time.

5 分
7

Discuss the mechanism: competing radical and non-radical pathways, the role of iodine and starch, and the concept of chemical oscillators.

5 分

予想される結果

The solution oscillates between colorless, amber, and deep blue 10–15 times before settling to a permanent dark blue. Each oscillation takes 10–30 seconds initially, with the period increasing as reactants are consumed.

後片付け

The spent solution contains iodine and manganese. Collect in inorganic waste. Rinse all glassware. Clean the magnetic stir bar.

詳細

カテゴリ
Classroom Demonstrations
難易度
Advanced (University)
所要時間
40 分
推定費用
$20.00
ステップ数
7
材料
7

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テルミット反応 30 min ドライアイス中でのマグネシウムの燃焼 25 min ナトリウムと水の反応 25 min ヨウ素時計反応 45 min ルミノールによる化学発光 30 min 密度カラム虹 30 min 消えるビーカー（屈折率マッチング） 15 min 瞬間凍結：過冷却水 120 min 象の歯磨き粉 20 min 非ニュートン流体：ウブレック 20 min

Frequently Asked Questions

What is the objective of 振動するブリッグス-ラウシャー反応?
三つの異なる色の状態を繰り返す化学振動反応を観察し、非線形化学動力学を実証する。
How difficult is 振動するブリッグス-ラウシャー反応?
This experiment is rated as Advanced (University). It takes approximately 40 minutes to complete.
What safety precautions are needed for 振動するブリッグス-ラウシャー反応?
Key safety precautions include: 30% H₂O₂ causes burns — handle with extreme care; H₂SO₄ is corrosive; KIO₃ is an oxidizer.
What materials are needed for 振動するブリッグス-ラウシャー反応?
The main materials required are: Potassium iodate (KIO₃), Malonic acid (CH₂(COOH)₂), Manganese(II) sulfate (MnSO₄), Starch solution (1%), Hydrogen peroxide (30%).
What results should I expect from 振動するブリッグス-ラウシャー反応?
The solution oscillates between colorless, amber, and deep blue 10–15 times before settling to a permanent dark blue. Each oscillation takes 10–30 seconds initially, with the period increasing as reactants are consumed.