La chimica รจ la disciplina che studia:
- la struttura e la composition of matter
- the changes that matter undergoes
- 's energy involved in the transformation of matter
SUBSTANCES AND MIXTURES
The matter is made of atoms, and may be in the form of:
- mixtures (or mixtures)
- substances (or substances as well)
MIXTURES
mixtures are a physical set of two or more substances, and may be:
- heterogeneous : not have a uniform composition and components are easily distinguishable.
- homogeneous : have uniform composition and the components are indistinguishable (eg sea water, wine, air). They are also called solutions.
The material consists mainly of mixtures.
METHODS OF SEPARATION
separating a mixture into its component pure substances are obtained.
These are the most widely used methods of separation:
- Filtration : separates the components of a heterogeneous mixture by exploiting the different particle size, and is accomplished by passing the mixture through a filter paper.
- Distillation : separating a mixture by exploiting the different boiling temperatures. It can be simple (separation of liquid from solid-liquid solution) or fractional (separation of liquid from liquid-liquid solution).
- chromatography : Get the speed with which the different components of the mixture migrate through a support material under the pressure of a stream of solvent.
- Centrifugation : due to the difference in density between the components of the mixture using centrifugal force.
- solvent extraction: is achieved by exploiting the solubility of one substance of the mixture in a given solvent.
