Everything you need to know about States of Matter



All matter exists in one of four states - gas, liquid, solid and plasma.

  • Open a bottle of perfume in one corner of a room, then move to the opposite corner and wait. In only a few minutes, you will be able to smell that perfume. Why is that? Because air is a gas and the perfume molecules evaporate into a gas and disperse into the gaseous air

  • Gas is a form of matter that does not have a definite volume or shape. Gases have low density compared to the same substance in other states. Gases are also able to diffuse easily, as shown in the perfume example.

  • GAS LAWS -                                                                                                                             Boyle’s Law: At constant temperature, the pressure of a fixed amount (number of moles) of gas is inversely proportional to its volume.                                                                       Charles’ Law: At constant pressure, the volume of a fixed mass of a gas is directly proportional to its absolute temperature.                                                                                 Kinetic molecular theory of gases:  Gases are made of large number of identical particles called molecules, which are very small. The actual volume of the molecules is negligible in comparison to the total volume of the molecules. They are considered as the point masses.  The forces of attraction and repulsion between the particles are supposed to be negligible at ordinary temperature and pressure.  Particles of a gas are always in constant and random motion.  Molecules are supposed to be perfectly hard spheres and the collisions between them are perfectly elastic.  The pressure exerted on the walls of the containing vessel is due to the collision of the molecules on the walls of the container.  The average kinetic energy of the particles of a gas is directly proportional to the absolute temperature of the gas.          Liquefaction of gases:  A gas can be liquefied by cooling or applying pressure or by the combined effect of both.

  • Now look at a bottle of water. What properties do you know about that liquid? You can tell that the liquid takes the shape of the bottle, and you probably know that if you pour the liquid water into a different container, it will take the shape of the new container. In a liquid, the molecules are more tightly packed but can still move and flow past each other. Liquids are able to diffuse and mix with other liquids, but it is a slower mixing than in gases. Another property common to all liquids is surface tension. Surface tension is a force of attraction that keeps molecules on the surface of a liquid together, causing tension. This is why bugs can walk on water.


  • Now look at a block of wood. Try to push on it. Have an elephant stand on it. What can you say about it? You can say that this solid block of wood has a definite volume and a definite shape. It doesn't change shape even with the elephant standing on it - unless of course he disintegrates it, but let's pretend this is a baby elephant. These are characteristics of a solid - it has a definite volume and shape. A solid has molecules too, they are just so tightly packed that they have limited movement and are incompressible and hold their volume and shape. In general, substances are most dense in the solid state.

The article written above is a brief overview of the various states of matter, and a little in detail about the types of gas laws and theories, hope this helps!!! Goodluck!!!