States of Matter
Chemistry commonly refers to three states of matter known as gases, liquids, and solids. Each of these have specific properties that define how the matter in each of these states act.
The gaseous state is one of the three main states of matter. Matter as a gas acts different compared to matter as a solid or liquid. Because gases have an indefinite shape and volume it will conform to the container it is in. For an example, an amount of gas can easily be held in a huge tank or the same amount can be held in a coke bottle and in each case it will fill the container and will take on its shape. Gas is made up of free moving particles, each particle can move independent of other at different rates as well as in different directions. Air is a gas. Gases can range from very reactive to almost inert. For instance if gaseous hydrogen and gaseous chlorine come in contact they violently combine, where as if gaseous oxygen and hydrogen contact they remain unchanged.
The liquid state is similar to the gaseous state in that it has not definite shape where as it does have a definite volume.