Magie Cháy Trong Băng Khô

Magie tiếp tục cháy trong cacbon dioxit rắn, khử CO₂ thành cacbon

Classroom Demonstrations Advanced (University) 25 phút ~$15,00

Mục tiêu

Minh họa magie có thể khử cacbon dioxit, thách thức quan niệm sai lầm rằng CO₂ luôn dập tắt đám cháy.

Bối cảnh

Magnesium burns so intensely (over 3000°C) that it can reduce carbon dioxide to elemental carbon. When a burning magnesium ribbon is placed in a cavity carved into dry ice (solid CO₂), it continues to burn brilliantly white, producing magnesium oxide (white powder) and elemental carbon (black specks). This reaction (2Mg + CO₂ → 2MgO + C) dramatically shows that CO₂ is not always an effective fire extinguisher and that thermodynamic favorability depends on the specific reactants involved.

Cảnh báo an toàn

  • Burning magnesium is extremely bright — never look directly at it without shade protection
  • Dry ice causes frostbite on contact — never handle with bare hands
  • Perform behind a safety shield
  • Keep a fire-resistant mat underneath
  • Do not attempt to extinguish burning Mg with water — explosion risk
  • Ensure ventilation — CO₂ accumulation in enclosed spaces is dangerous

PPE cần thiết

goggles gloves lab_coat face_shield

Vật liệu

  • Magnesium ribbon (30 cm)
    Clean, bright surface
  • Dry ice block (1 kg)
    Solid CO₂ (−78.5°C)
  • Tongs (long-handled) (1)
    For handling dry ice

Thiết bị

Safety shield Fire-resistant mat Chisel or screwdriver (for carving cavity in dry ice) Lighter or matches Welding goggles or #14 shade glass

Quy trình

1

Using tongs, carve a small cavity (about 3 cm deep) in the dry ice block. Place the dry ice on a fire-resistant mat.

3 phút Wear insulated gloves for dry ice
2

Set up the safety shield between the demonstration and the audience. Distribute welding goggles or instruct everyone to look away when ignited.

2 phút
3

Light one end of the magnesium ribbon. Once burning, quickly place it in the dry ice cavity using tongs.

2 phút Do not look directly at the flame
4

Place another piece of dry ice on top to create a CO₂ atmosphere around the burning magnesium.

2 phút
5

Observe: the magnesium continues to burn with an intense white flame inside the CO₂ environment. It does NOT go out.

3 phút Maintain safe distance
6

After the reaction, examine the residue: white MgO powder and black carbon specks. Discuss the reaction: 2Mg + CO₂ → 2MgO + C.

8 phút Wait for residue to cool completely
7

Discuss implications for fire safety: why Mg fires cannot be extinguished with CO₂, water, or standard fire extinguishers.

5 phút

Kết quả dự kiến

The magnesium continues to burn brilliantly inside the dry ice. After the reaction, white MgO and black carbon specks are visible in the dry ice cavity. This proves CO₂ has been reduced to elemental carbon.

Dọn dẹp

Allow all residues to cool and dry ice to sublimate. Sweep up MgO and carbon residue. No chemical waste disposal needed.

Chi tiết

Danh mục
Classroom Demonstrations
Độ khó
Advanced (University)
Thời gian
25 phút
Chi phí ước tính
$15,00
Số bước
7
Vật liệu
3

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 Kem Đánh Răng Voi 20 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 Magie Cháy Trong Băng Khô?
Minh họa magie có thể khử cacbon dioxit, thách thức quan niệm sai lầm rằng CO₂ luôn dập tắt đám cháy.
How difficult is Magie Cháy Trong Băng Khô?
This experiment is rated as Advanced (University). It takes approximately 25 minutes to complete.
What safety precautions are needed for Magie Cháy Trong Băng Khô?
Key safety precautions include: Burning magnesium is extremely bright — never look directly at it without shade protection; Dry ice causes frostbite on contact — never handle with bare hands; Perform behind a safety shield.
What materials are needed for Magie Cháy Trong Băng Khô?
The main materials required are: Magnesium ribbon, Dry ice block, Tongs (long-handled).
What results should I expect from Magie Cháy Trong Băng Khô?
The magnesium continues to burn brilliantly inside the dry ice. After the reaction, white MgO and black carbon specks are visible in the dry ice cavity. This proves CO₂ has been reduced to elemental carbon.