States of Matter and Mixtures: Changes of State

Matter exists in three states: solid, liquid and gas; the state of matter is determined by the arrangement and energy of its particles.
Solids have a fixed shape and volume. They cannot be compressed or flow as their particles are packed together in a fixed pattern.
Liquids take the shape of their container, yet have a fixed volume. They cannot be compressed yet they can flow, as their particles are close but can move past each other.
Gases take the shape and volume of their containers. They can be compressed and they can flow easily as their particles are far apart and move freely.
Matter can change from one state to another through different processes: freezing, melting, condensing, boiling or evaporating, and sublimation.
Melting occurs when a solid is heated and turns into a liquid; the temperature at which this happens is called the melting point.
Freezing is the process of a liquid cooling and turning into a solid; the temperature at which a liquid solidifies is the freezing point.
When a liquid is heated, it may turn into a gas; this process is known as boiling or evaporation, and the temperature at which it occurs is the boiling point.
Condensation is when a gas cools down and turns into a liquid; the temperature at which this happens is the condensation point.
Sublimation is the process by which a solid changes directly into a gas without becoming a liquid first or vice versa.
The process of changing from solid to liquid and gas, or from gas to liquid then solid, is known as a phase change or change of state.
During a change of state, the temperature remains constant until all the substance has changed state. This is because energy is used to change the state, not to increase the temperature.
Factors affecting boiling and melting points include type of particles, size of particles, and forces of attraction between particles.
Mixtures are made up of two or more states of matter and can be separated by various methods such as distillation, evaporation, chromatography, or filtration. The method used depends on the type of mixture needing to be separated.