Chemistry-Atomic

What is an atom?

All substances are made from atoms. Each element in the periodic table is made up of one kind of atom. An atom has a small nucleus surrounded by electrons. When two or more elements react and combine they are called compounds.

Chemical Equations

Chemical equations always have reactants and products. The reactants are on the left and react to create the products which happen to be on the left. When an equation takes place you should always write the states of matter(g(gas)(s(solid)(aq(aqueous). You should always balance an equation. By balancing the equation you allow the law of conservation to take place.

Law of conservation- The law of conservation of mass states that no atoms are lost or made when a chemical reaction takes place. The mass of products should always equal the reactants. Sometimes this does not seem to be proven correct, this is because gases may escape into the atmosphere. Normally if the law is broken it's due to the gas oxygen.

There are 3 main methods of seperating mixtures.

Filtration-Separates a substance insoluble in a solvent from those that are soluble in a solvent. Sand and salt can be separated using filtration. 

Crystallisation-Separates a soluble solid from a solvent.

Distillation-Separates a solvent from soluble solids dissolved in the solvent.Seawater is distilled to obtain usable water.