The state of matter where molecules are further apart is called a gas. In a gas, the molecules have high energy and move quickly, so they are less likely to be close together. Gases are also characterized by their low density, since the molecules are so spread out.

The opposite of a gas is a solid, where the molecules are very close together and packed tightly. In between a gas and a solid is a liquid, where the molecules are not as close together as in a solid, but not as far apart as in a gas.

The state of matter of a substance depends on its temperature and pressure. As the temperature increases, the molecules move faster and become more spread out, so the substance will change from a solid to a liquid to a gas. As the pressure increases, the molecules are forced closer together, so the substance will change from a gas to a liquid to a solid.