1. BY: MARY BRODEUR NATE BROWN MADELYN DOUGLAS MARISSA SCAVELLO Precipitation

2. Description A precipitation reaction is when soluble ions in two solutions are mixed together to form a compound that is set aside from the solution as a solid That insoluble compound is called a precipitate The solid precipitate can be seen in the solution

3. Example 1 An aqueous solution of calcium chloride mixes with sodium sulfate CaCl 2 (aq) + Na 2 SO 4 (aq)  CaSO 4 (s) +2NaCl(aq) The solid calcium sulfate forms as a product of the reaction This solid is also called gypsum, which is used in drywall

4. Example 2 Lithium Bromide and Silver Nitrate is added to produce Lithium Nitrate and Silver Bromide (the precipitate) LiBr (aq) + AgNO3 (aq)  LiNO3 (aq) + AgBr (s) Silver bromide is used in the production of film for photography.

5. Why is precipitation important? Useful for determining what elements are present in a solution  Ex: If a precipitate is formed when a chemical reacts with iron one could test for iron in water sources by seeing if a precipitate forms Used to extract elements  Ex: Magnesium from seawater

6. Works Cited "Calcium Sulfate Fillers." USG. United States Gypsum Company, 5 Nov. 2005. Web. 24 May 2012.. "Precipitation Reaction." CHEMPATHS. Chemical Education Digital Library, n.d. Web. 24 May 2012.. "Precipitation Reactions." Clackamas Community College Distance Learning. N.p., n.d. Web. 24 May 2012.. Schaffer, Julie, and Corinne Herman. "Precipitation Reactions." CHEMWiki. UC Davis, 3 June 2011. Web. 24 May 2012..