아이오딘 시계 반응

예측 가능한 지연 후 갑자기 짙은 파란색으로 변하는 반응

Classroom Demonstrations Intermediate (High School) 45 분 ~$10.00

목표

아이오딘 시계 반응을 이용하여 반응 역학과 농도 및 온도가 반응 속도에 미치는 영향을 실증한다.

배경

The iodine clock reaction is a classic demonstration of chemical kinetics. Two colorless solutions are mixed and after a predictable delay, the solution suddenly turns dark blue. The delay occurs because bisulfite (HSO₃⁻) rapidly reduces any I₂ produced back to I⁻ (the clock mechanism). When all the bisulfite is consumed, I₂ accumulates and reacts with starch to produce the dramatic blue-black color. By varying concentration or temperature, students can explore factors affecting reaction rate.

안전 경고

  • H₂SO₄ is corrosive
  • NaHSO₃ releases SO₂ gas if over-acidified — work in ventilated area
  • KIO₃ is an oxidizer
  • Hot plate surfaces are a burn hazard

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • Potassium iodate (KIO₃) (2 g)
    Solution A
  • Sodium bisulfite (NaHSO₃) (1 g)
    Solution B
  • Starch solution (1%) (10 mL)
    Indicator in Solution B
  • Sulfuric acid (0.5M H₂SO₄) (20 mL)
    Solution A acidification
  • Distilled water (500 mL)

장비

Beakers (250 mL, 4) Magnetic stirrer Stopwatch Thermometer Graduated cylinders Hot plate Ice bath

실험 절차

1

Prepare Solution A: Dissolve 2 g KIO₃ in 200 mL water, add 20 mL of 0.5M H₂SO₄.

5 분
2

Prepare Solution B: Dissolve 1 g NaHSO₃ in 200 mL water, add 10 mL of 1% starch solution.

5 분
3

Trial 1 (baseline): Mix 50 mL of A with 50 mL of B and start the stopwatch immediately. Record the time until the solution turns blue.

5 분
4

Trial 2 (concentration effect): Mix 25 mL of A + 25 mL water with 50 mL of B. Record the time. It should take approximately twice as long.

7 분
5

Trial 3 (temperature effect): Warm both solutions to 40°C. Mix 50 mL of each and record the time. It should be significantly shorter.

8 분 Handle warm solutions carefully
6

Trial 4 (cold): Cool both solutions to 10°C in an ice bath. Mix and record the time.

8 분
7

Plot reaction time vs. concentration and temperature. Discuss rate law, activation energy, and the Arrhenius equation.

7 분

예상 결과

The blue color appears suddenly after a delay of 5–60 seconds depending on conditions. Doubling concentration roughly halves the time. Increasing temperature by 10°C roughly halves the time (consistent with the Arrhenius equation).

정리

Pour reacted solutions down the drain with water. Rinse all glassware. Clean the magnetic stirrer.

세부 정보

카테고리
Classroom Demonstrations
난이도
Intermediate (High School)
소요 시간
45 분
예상 비용
$10.00
단계
7
재료
5

더 많은 실험

드라이아이스 속 마그네슘 연소 25 min 진동하는 브릭스-라우처 반응 40 min 나트륨과 물의 반응 25 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 아이오딘 시계 반응?
아이오딘 시계 반응을 이용하여 반응 역학과 농도 및 온도가 반응 속도에 미치는 영향을 실증한다.
How difficult is 아이오딘 시계 반응?
This experiment is rated as Intermediate (High School). It takes approximately 45 minutes to complete.
What safety precautions are needed for 아이오딘 시계 반응?
Key safety precautions include: H₂SO₄ is corrosive; NaHSO₃ releases SO₂ gas if over-acidified — work in ventilated area; KIO₃ is an oxidizer.
What materials are needed for 아이오딘 시계 반응?
The main materials required are: Potassium iodate (KIO₃), Sodium bisulfite (NaHSO₃), Starch solution (1%), Sulfuric acid (0.5M H₂SO₄), Distilled water.
What results should I expect from 아이오딘 시계 반응?
The blue color appears suddenly after a delay of 5–60 seconds depending on conditions. Doubling concentration roughly halves the time. Increasing temperature by 10°C roughly halves the time (consistent with the Arrhenius equation).