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Physical Chemistry

Plasma

Definition and meaning of Plasma in chemistry.

Plasma is the fourth state of matter, consisting of a highly ionized gas containing approximately equal numbers of positive ions and free electrons. It is formed when a gas is heated to extreme temperatures or subjected to a strong electromagnetic field, causing electrons to strip away from their atoms.

In more detail

Because it contains a large concentration of free charge carriers, plasma is highly electrically conductive and responds strongly to external magnetic and electric fields. Unlike a normal neutral gas, plasma can carry substantial electrical currents and generate its own complex magnetic fields. It is the most abundant form of ordinary matter in the universe, making up stars, the solar wind, and the interstellar medium, though it is rare on Earth's surface under natural conditions. Containing and manipulating plasma is a major focus in the development of controlled nuclear fusion for energy production.

Key facts

FieldPhysical Chemistry
CompositionPositive ions and free electrons
Defining propertyHigh electrical conductivity
AbundanceMost common state of ordinary matter in the universe
Example

The glowing gas inside a neon sign is a form of plasma, created when high voltage is applied to the neon gas, ionizing it and causing it to emit colored light.

Frequently asked questions

How is plasma different from a gas?

A gas consists of neutral molecules, while plasma consists of charged particles, giving plasma distinct electromagnetic properties such as the ability to conduct electricity.

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