The objective of this experiment is to become familiar with the methods of separating substances from one another using decantation, extraction, and sublimation techniques. Most materials in our surroundings are mixtures of two or more substances in which each substance retains its own chemical identity and therefore its own properties. Mixtures are either homogeneous or heterogeneous. Mixtures that don't have the same composition, properties, and appearance throughout the mixture are called Heterogeneous. Mixture that are uniform in composition, properties, and appearance throughout are called homogeneous. Sugar water is a homogeneous mixture and rocks is a heterogeneous mixture. Homogeneous and heterogeneous mixtures can be separated into their components by several physical methods. The methods that will use for the separation depend on differences in physical properties such as decantation, filtration, extraction and sublimation. The process of separating a liquid from a solid (sediment) by gently pouring the liquid from the solid so as not to disturb the solid is Decantation. Filtration is the process of separating a solid from liquid by means of a porous substance –a filter- which allows the liquid to pass through but not the solid. Extraction is the separation of a substance from a mixture by preferentially dissolving that substance in a suitable solvent. Also, the process in which a solid passes directly to the gaseous state and back to the solid state without the appearance of the liquid state is called Sublimation. Experimental:
The materials that we use it in this experiment are unknown mixture of sodium chloride, ammonium chloride, and silicon dioxide. Also, we use some apparatus such as balance, tongs, evaporating dishes (2), watch glass, 50 or 100 ml graduated cylinder, clay triangles (2) or wire gauze (2), glass stirring rods, ring stands (2), iron rings...
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