Topic one - Principle of chemistry

Solids, liquids and gases:

• Solids have a fixed volume and shape
• Liquids don't change volume but have no definite shape, tey take up the shap of the container they are in 
• Gas has no fixed volume or shape, they spread to fill their container

Diffusion:

When potassium managnate(VII) dissolves in water the water slowly all turns purple because of the random motion of particles in a liquid the purple colour eventually evenly spreads out.

Another experiment that can be used to show diffusion is bromine gas and air, you fill half a gas jar with bromine and half with air then when you remove the lids seperating the two gases then if you leave it for long enough , because of kinetic theory, the particles of bromine gas move around randomly (random motion) so both jars are filled with bromine.

Mixtures and compounds:

Mixture- Two or more substances that are combined without a chemical reaction soo can be seperated easily

Compound - When atoms join together in a chemical reaction , the compound has very different properties than the elements they derived from and they can only be seperated through another chemical reaction.

Distillation seperates a liquid and a solid, one example being seperating salt and water.

Fractional distillation seperates mixtures of liquids and relies on how liquids boil at different temperatures.

Filtration also serperates solids from liquids , the mixture passes through filter paper and the liquid goes through but the solid is left behind. 

Crystallisation , when a solid is dissolved in water , you can just evaporate the water so only the solid is left behind. 

Chromotography paper:

Chromotography can be used to seperate a mixture of solids that are soluble, it is often used on inks and dyes. To seperate the different dyes in an ink a spot of ink must be put at the bottom of the chromatogograhy paper , then make sure some of the paper , below the ink, is in water. As the water spreads throuought the paper the dyes are carried with the water and they begin to seperate , this is because different dyes have different solubilities and are carried at different speeds along the paper.

Atomic structure:

Atoms are made of smaller , sub-atmoic particles , the main three ones are protons, neutrons and electrons.

Because the protons in the nucleus have a positive charge and the neutrons have no charge the nucleus is postitivley charged , which keeps the elctrons orbiting it in their shells as they are negaticley chraged so they attract.

Isotopes:

Isotopes are atoms which have the same number of protons as elctrons but have a different number of neutrons.                                                                                                …