# Pure Substances and Mixtures

Topics: Gas, Particle physics, Temperature Pages: 2 (506 words) Published: May 7, 2013
What is the particle theory?
The particle theory says that that matter consists of many small particles with spaces in between. The particles are constantly moving, the higher it’s temperature, the faster they move. All the particles are attracted to each other. The particles move faster and move further apart when heated, and the reverse when cooled. Each substance has unique particles that are different from the particles of other substances. Particle theory helps to explain the behaviour of materials by showing a model which allows us to All matter are made up picture what is happening inside those materials. Particles in each of the 3 states of matter behave differently. In a of particles. solid, the particles are very close and strongly attracted to each other. They can vibrate, but they cannot move from one place to another. They always stay in their positions, creating a deﬁned shape and volume. In a liquid, the particles have weaker attraction and are not as close to each other as solids. They can move around in all directions so liquid does not have a deﬁned shape, but their movements are still limited by attractions between particles. Their movements are also limited by the walls of their containers, which is why liquids will take the shape of it’s container. Particles of gases are further apart from each other than particles in solids and liquids and their attraction forces are very weak. They can move in all directions freely within a container bumping against the walls of the container and against other particles. Gases take the shape of their containers just like liquids do, and how they move or vibrate. but they can escape very easily.

When you add heat to a solid, will it expand or contract?
It will expand. When any matter is heated it will expand and when it is cooled it will contract, with very few exceptions. They expand because the particles vibrate faster when heated. The number of particles and the size of each particle remains the...