What are the chemical reaction happen indise lamp in tungsten

In summary, the conversation discusses the use of incandescent lamps with tungsten filaments and the addition of iodine to the gas surrounding the filament. The presence of iodine helps prolong the lifespan of the lamp by reacting with the tungsten to form tungsten iodide, which then vaporizes and diffuses back to the filament. This process occurs at high filament temperatures. The Van Arkel - de Boer method may also be relevant to this topic.
  • #1
kimdesug
9
0
Also the chemical involve in the W and iodine. Thx
 
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  • #2
Welcome to PF.
Your question is unclear.
Do you mean an incandescent lamp with a tungsten filament?
There are no chemical reactions to make the filament glow - the metal heats up until it glows. Reactions with air will reduce the lifetime of the bulb so we want to avoid them.

Don't know what you mean by "in the W and iodine".
 
  • #3
I suppose he refers to halogen lamps. There some halogen like iodine is added to the gas surrounding the filament. It reacts with the tungsten at the cooler quartz surface (which still has some hundred degrees centigrade) to form tungsten iodide which vaporizes and diffuses back to the filament where it decomposes again into tungsten and elementary iodide. This helps to prolong the livetime of the lamp and use them at higher filament temperatures.

PS: Maybe more adequate to be discussed in the chemistry forum
 
  • #4
sorry for unclear question, I want to know what happen in the incandescent lamp which add 0.1 mg of iodine. Thx for DrDu, I can picture something.
 
  • #5
You may also look for: Van Arkel - de Boer method
 
  • #6
thank!
 

1. What is the chemical reaction that happens inside a tungsten lamp?

The chemical reaction that occurs inside a tungsten lamp is called incandescence. This is when the tungsten filament is heated to a high temperature, causing it to emit visible light.

2. How does the tungsten filament get heated?

The tungsten filament is heated through the process of electrical resistance. When an electric current is passed through the filament, it encounters resistance, which then creates heat.

3. What role does the gas inside the lamp play in the chemical reaction?

The gas inside the lamp, typically a mixture of argon and nitrogen, acts as a buffer and helps to prevent the tungsten filament from burning up too quickly. It also helps to create a more stable and consistent light output.

4. What happens to the tungsten filament during the chemical reaction?

During the chemical reaction, the tungsten filament reaches temperatures of up to 3,000 degrees Celsius. This causes the filament to glow and emit visible light. However, over time, the filament will gradually evaporate and thin out, eventually leading to the bulb burning out.

5. Is the chemical reaction in a tungsten lamp reversible?

No, the chemical reaction in a tungsten lamp is not reversible. Once the tungsten filament has evaporated and the bulb has burnt out, it cannot be restored to its previous state. This is why tungsten lamps have a limited lifespan and need to be replaced periodically.

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