What do you understand by gas?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Gas**: A gas is one of the four fundamental states of matter, characterized by its ability to expand and fill the volume of its container.

2. **Inter-particle Attractions**: In gases, the inter-particle attractions are very weak compared to solids and liquids. This means that the particles in a gas do not hold together tightly and can move freely.

3. **Particle Arrangement**: The particles in a gas are spaced far apart from each other. This is in contrast to liquids, where particles are closer together, and solids, where particles are tightly packed.

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