Experiment: Separation of Mixtures1 Separation of Mixtures ObjectivesTo separate a mixture by using the unique physical properties of compounds. To examine techniques for separation using physical methods. To calculate percent composition of a mixture. IntroductionIn chemistry, matter is generally classified into two broad categories: pure substances and mixtures. A pure substance is a type of matter that has a fixed composition. The two types of pure substances are elements and compounds. An element is a substance that cannot be broken down into simpler pure substances. A compound is a substance that is composed of two or more elements which are chemically combined in a fixed proportion by mass. Very few of the materials we encounter on a daily basis are pure. A mixture is a substance that consists of two or more pure substances that are physicallycombined. Mixtures are not new to chemistry; we use and consume them on a daily basis. The beverages we drink and the fuel we use in our automobiles are mixtures. The ground we walk on contain mixtures, the air we breathe is a mixture of several gases, and ocean water is also a mixture of several different substances. Separating a mixture can be done by taking advantage of differences in some physical or chemical properties of the individual components in the mixture. Chemists have developed techniques to isolate pure components from mixtures. These methods take advantage of the differences in physical properties of the components. The following techniques will be demonstrated in this laboratory: 1.Sublimation: This process involves heating a solid until it passes directly from the solid phase into the gaseous phase. The reverse process, when the vapor returns to the solid phase without a liquid state in between, is called deposition. Some solids that sublime are iodine, caffeine, and naphthalene (mothballs). 2.Extraction: This process uses a solvent to selectively dissolve one or more components from a solid mixture. With this technique, a soluble solid can be separated from an insoluble solid. 3.Decantation: This process separates a liquid from an insoluble solid sediment by carefully pouring the liquid from the solid without disturbing the solid. 4.Filtration: This process separates a solid from a liquid through the use of a porous material as a filter. Paper, charcoal, or sand can serve as a filter. These materials allow the liquid to pass through but not the solid. 5.Evaporation: This is the process of heating a mixture and drive off, in the form of vapor, a volatile liquid component, in order to make the remaining component dry.All of these techniques involve change in the physical state of a chemical compound, whether it is a solid, liquid, gas, or present in a solution; no chemical bonds have been broken in undergoing a transformation from one state to another. In this lab exercise, a mixture of Iron, NaCl, SiO2 (sand), and Naphthalene (C10H8) will be separated by utilizing the difference in the physical properties of these four components. The separation will be done according to the scheme presented in the following diagram.