Classification of Matter Worksheet

Separating Mixtures: A mixture is a PHYSICAL combination, so separation involves a PHYSICAL change 1. Filtration: separation of a soluble substance from an insoluble substance; separation based on solubility EXAMPLE: separating sugar from sand a. add water to the sugar and sand mixture until all of the Sugar dissolves b. set up a funnel with filter paper as shown below funnel setup for filtration c. slowly pour the mixture through the filter paper set-up d. the water and the soluble Sugar will pass straight through the filter paper, and the insoluble sand will be left behind on the filter paper e. if the water in the beaker below the funnel is allowed to evaporate, the Sugar will be left in the bottom of the beaker   2. Chromatography: separation based on abilities of substances to attract to various solids such as paper or starch EXAMPLE: separating the dyes in ink (see p. 458 in text) a. inks are placed on bottom end of a filter paper   b. filter paper is placed into a test tube or beaker containing a solvent such as water or alcohol c. colors in the ink will travel different speeds up the paper based on their attraction for the paper (more attraction, travel faster)   2. Distillation: separation of the components of a solution, such as salt water or alcohol and water; separation is based on boiling points; the substance with a lower boiling point will turn into a vapor first, travel through the tube, and then condense back into a liquid BP H₂O = 100°C BP Salt = 800°C EXAMPLE: separating salt from water a. the solution of salt water is heated b. the water has a lower boiling point than salt so it will boil and vaporize first c. the water vapor rises and collects in the condenser tube where it cools and becomes a liquid d. pure water drips into the receiving flask and the salt remains in the original boiling flask BP alcohol = 80°C BP H₂O = 100°C EXAMPLE: separating water from alcohol a. heat the solution b. alcohol has a lower boiling point than water so it will boil and vaporize first c. the alcohol vapor travels through the condensing tube and cools d. pure alcohol drips into the receiving flask and pure water remains in the original flask PRACTICE: Give a clear description of how you would separate the following mixtures: Sugar 1 from water   Distillation will separate Sugar water Salt from sand Add water, salt dissolves, sand does not. Filtration will separate them. Sawdust from sand Add water, sawdust is less dense than water, floats on top, it can be scooped off, sand sinks Iron filings from sand Use a magnet, it will separate magnetic iron from sand Colors in green ink Chromatography will separate the blue + yellow ink that make green. Part 1: Read the following information on elements, compounds and mixtures. Fill in the blanks where necessary. Elements: A pure substance containing only one kind of atom   An element is always uniform all the way through (homogeneous). An element cannot be separated into simpler materials (except during nuclear reactions). Over 100 existing elements are listed and classified on the Periodic Table.   Compounds: A pure substance containing two or more kinds of atoms The atoms are chemically combined in some way. Often times (but not always) they come together to form groups of atoms called molecules.   A compound is always homogeneous (uniform). Compounds cannot be separated by physical means. Separating a compound requires a chemical reaction.   The properties of a compound are usually different than the properties of the elements it contains.