Separation and Identification | Introduction
Introduction
Most natural and manufactured materials are mixturesA combination of two or more substances that are not chemically combined with each other and that can exist in any proportion., not pure substances. In a mixture, each of the substances has its own chemical properties. Salt water, gravel, and cookies are a few examples of mixtures. People can use physical means to separate mixtures into their component parts. Separating mixtures is important because it allows people to identify the substances that make up the mixture.
Separating the components in a substance is usually one of the first steps in identifying its components. All mixtures can be separated and identified by the distinguishing chemical or physical properties of the components. The separation technique chosen depends on the type of mixture and its characteristics. After a mixture is separated, one or all of its components can be identified. Researchers can match the properties of the unknown substance to those properties of a known substance. Appearance and the way the unknown substance reacts with other substances are ways to identify a substance.
Separation and identification techniques are used for all types of different purposes. If there are pollutants in the water, scientists first separate and identify the pollutants to clean the water. Forensic scientists, people who work in criminal investigations, use the techniques to identify evidence, such as fabrics or blood. Research scientists will separate unknown biological samples to identify the molecules in the sample. In blood tests doctors may need to identify and then separate iron or another component out of the blood.