Change of state
The diagram summarises the common changes of Solid, liquid or gas. Evaporation is a change of state from liquid to gas..
Some substances can change directly from solid to gas without becoming a liquid in between. This is called When a solid turns straight into a gas on heating, without becoming a liquid first - or when a gas turns straight into a solid, without becoming a liquid.. Solid carbon dioxide ('dry ice') and iodine can Able to change from a solid to a gas, or from a gas to a solid, without becoming a liquid..
Physical and chemical change
Changes of state are physical changes. The substance remains the same.
It is only during a chemical change that a new substance is formed.
Limitations of the particle model - Higher
The The scientific theory used to explain the properties of solids, liquids and gases. It involves the arrangement and movement of the particles in a substance. represents A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. as inelastic spheres.
It makes a number of simplifications:
- it assumes that particles are spheres
- it represents spheres as the same size
- the gap between The smallest part of an element that can exist. in a gas are small enough to make a diagram fit on the page, they should be much larger
- differences in the forces of attraction between particles are not fully explained
This means that there is a limit to what the particle model can explain. For example, it cannot explain why substances have different The temperature at which a solid changes into a liquid as it is heated. and boiling points.