Which of the following describes a gas?

O

A. Does not have a fixed volume or a fixed shape

O

B. Has a fixed volume and a fixed shape

O

C. Has a fixed shape but not a fixed volume

O

D. Has a fixed volume but not a fixed shape

A is the answer. A gas never has a fixed volume or shape

A. Does not have a fixed volume or a fixed shape.

Explanation:

A liquid is matter that has a fixed volume but not a fixed shape. A gas is matter that has neither a fixed volume nor a fixed shape. Like a gas, plasma lacks a fixed volume and shape.

Liquids have a fixed volume but no fixed shape. This is because the particles in a liquid are further apart than the particles in a solid, allowing them to easily slide past each other. Solids have a fixed shape because their molecules are so tightly packed they cannot do much more than vibrate against each other.

You might ask, What is a definite shape?

Any matter that is a solid has a definite shape and a definite volume. The molecules in a solid are in fixed positions and are close together. Although the molecules can still vibrate, they cannot move from one part of the solid to another part. As a result, a solid does not easily change its shape or its volume.