Kem Đánh Răng Voi

Phân hủy xúc tác nhanh hydro peroxit tạo cột bọt khổng lồ

Classroom Demonstrations Beginner (Middle School) 20 phút ~$10,00

Mục tiêu

Minh họa sự phân hủy xúc tác hydro peroxit dùng kali iotua, minh họa các khái niệm xúc tác, phản ứng tỏa nhiệt và sinh khí.

Bối cảnh

Elephant toothpaste is one of the most popular chemistry demonstrations. Concentrated hydrogen peroxide (H₂O₂) is decomposed rapidly by a potassium iodide (KI) catalyst, releasing oxygen gas and steam. When performed in a narrow-neck flask with dish soap, the oxygen gas creates a towering column of foam that erupts like giant toothpaste. The reaction is exothermic, and the foam is warm to the touch. The iodide ion acts as a catalyst by cycling between I⁻ and IO⁻ intermediates.

Cảnh báo an toàn

  • 30% H₂O₂ causes severe skin burns and eye damage
  • Wear face shield and heavy-duty gloves
  • Do not stand over the flask when adding KI
  • The foam is hot — do not touch immediately
  • Perform behind a safety shield

PPE cần thiết

goggles gloves lab_coat face_shield

Vật liệu

  • Hydrogen peroxide (30%) (50 mL)
    30% concentration required for dramatic effect
  • Potassium iodide (KI) (10 g)
    Dissolved in 25 mL water
  • Liquid dish soap (15 mL)
  • Food coloring (5 drops)
    Optional, for visual effect
  • Large tray or bin (1)
    To catch overflow

Thiết bị

Erlenmeyer flask (1 L, narrow neck) Measuring cylinder Safety shield or splash guard Funnel

Quy trình

1

Place the Erlenmeyer flask on the large tray. Set up the safety shield.

2 phút Ensure audience is at safe distance
2

Carefully pour 50 mL of 30% H₂O₂ into the flask.

2 phút 30% H₂O₂ is extremely corrosive
3

Add 15 mL of dish soap and a few drops of food coloring. Swirl gently to mix.

2 phút
4

Dissolve 10 g of KI in 25 mL of warm water. Pour this solution into the flask using a funnel and step back immediately.

2 phút Step back immediately after adding
5

Observe the rapid evolution of foam. The reaction is complete in seconds. Discuss the role of KI as a catalyst.

5 phút
6

After the foam cools, students may touch it (with gloves). It contains only water, oxygen, soap, and KI — no H₂O₂ remains.

5 phút Wait until foam is cool

Kết quả dự kiến

A dramatic eruption of warm, colored foam that rises 1–2 meters above the flask. Steam may be visible. The reaction demonstrates catalysis (KI is not consumed), exothermic processes, and gas evolution (O₂).

Dọn dẹp

The foam is non-toxic (soap, water, KI). Rinse down the drain with plenty of water. Clean the flask and tray.

Chi tiết

Danh mục
Classroom Demonstrations
Độ khó
Beginner (Middle School)
Thời gian
20 phút
Chi phí ước tính
$10,00
Số bước
6
Vật liệu
5

Thí nghiệm khác

Chất Lỏng Phi Newton: Oobleck 20 min Cốc Thủy Tinh Biến Mất (Khớp Chiết Suất) 15 min Cột Cầu Vồng Mật Độ 30 min Đóng Băng Tức Thì: Nước Siêu Lạnh 120 min Magie Cháy Trong Băng Khô 25 min Phản Ứng Dao Động Briggs-Rauscher 40 min Phản Ứng Đồng Hồ Iot 45 min Phản Ứng Natri với Nước 25 min Phản Ứng Thermit 30 min Phát Quang Hóa Học với Luminol 30 min

Frequently Asked Questions

What is the objective of Kem Đánh Răng Voi?
Minh họa sự phân hủy xúc tác hydro peroxit dùng kali iotua, minh họa các khái niệm xúc tác, phản ứng tỏa nhiệt và sinh khí.
How difficult is Kem Đánh Răng Voi?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for Kem Đánh Răng Voi?
Key safety precautions include: 30% H₂O₂ causes severe skin burns and eye damage; Wear face shield and heavy-duty gloves; Do not stand over the flask when adding KI.
What materials are needed for Kem Đánh Răng Voi?
The main materials required are: Hydrogen peroxide (30%), Potassium iodide (KI), Liquid dish soap, Food coloring, Large tray or bin.
What results should I expect from Kem Đánh Răng Voi?
A dramatic eruption of warm, colored foam that rises 1–2 meters above the flask. Steam may be visible. The reaction demonstrates catalysis (KI is not consumed), exothermic processes, and gas evolution (O₂).