진동하는 브릭스-라우처 반응

무색·호박색·짙은 파란색 사이를 순환하는 화학 시계

Classroom Demonstrations Advanced (University) 40 분 ~$20.00

목표

세 가지 다른 색 상태 사이를 반복적으로 순환하는 화학 진동 반응을 관찰하고, 비선형 화학 역학을 실증한다.

배경

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).

안전 경고

  • 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

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • 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)

장비

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

실험 절차

1

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

5 분 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 분
3

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

3 분 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 분 Step back after mixing
5

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

15 분
6

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

5 분
7

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

5 분

예상 결과

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.

정리

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

세부 정보

카테고리
Classroom Demonstrations
난이도
Advanced (University)
소요 시간
40 분
예상 비용
$20.00
단계
7
재료
7

더 많은 실험

드라이아이스 속 마그네슘 연소 25 min 나트륨과 물의 반응 25 min 아이오딘 시계 반응 45 min 사라지는 비커(굴절률 매칭) 15 min 코끼리 치약 20 min 테르밋 반응 30 min 루미놀 화학발광 30 min 비뉴턴 유체: 우블렉 20 min 밀도 컬럼 무지개 30 min 순간 냉동: 과냉각수 120 min

Frequently Asked Questions

What is the objective of 진동하는 브릭스-라우처 반응?
세 가지 다른 색 상태 사이를 반복적으로 순환하는 화학 진동 반응을 관찰하고, 비선형 화학 역학을 실증한다.
How difficult is 진동하는 브릭스-라우처 반응?
This experiment is rated as Advanced (University). It takes approximately 40 minutes to complete.
What safety precautions are needed for 진동하는 브릭스-라우처 반응?
Key safety precautions include: 30% H₂O₂ causes burns — handle with extreme care; H₂SO₄ is corrosive; KIO₃ is an oxidizer.
What materials are needed for 진동하는 브릭스-라우처 반응?
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 진동하는 브릭스-라우처 반응?
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.