A Double Reflection Reaction

Introduction: Double displacement reactions have many applications and can be found in both nature and in a lab. Scientist often need to produce new materials using double displacement reactions. The equation for double displacement reactions is:

AB + CD -> AC + DB

A double displacement reaction results in 2 new compounds which are classified as the products. The reactants are the compounds before undergoing a chemical reaction. The cations and anions of each compound found in the reactants are being rearranged to form two entirely different compounds. The driving force that causes this and all types of chemical reactions is the collision reaction theory. The collision reaction theory states that when chemicals mix, the chemicals will collide. If the chemicals collide at the proper speed and position, the result will be a breaking of the previous bonds and formation of new bonds. Therefore in a double displacement reaction chemicals AB and CD will first split apart, and during the rearrangement they will form AC and DB.

Often times these double displacement reactions will result in the formation of a precipitate. A precipitate is defined as the creation of a solid with a solution. A solution is a homogeneous mixture of two or more substances. Solutions are commonly an ionic or molecular compound that has been dissolved/dissociated in water. In ionic compounds the water enters into the spaces within the crystal lattice structure and weakens the forces holding the molecule together. This causes the ions to completely dissociate from one another and allows for them to rejoin to other ions not found in the original solution. One is able to predict the formation of a precipitate ...

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...of chemicals only to have a large amount being wasted.

This lab determines the percentage yield of a double displacement reaction between 2.00g of strontium chloride(s) and 2.00g of copper (II) sulfate pentahydrate(s). The two chemicals were added to 40 ml of water then mixed together in order to undergo a chemical reaction. After adequate precipitate had been formed, the solution was then passed through filter paper in order to separate the solid precipitate from the original solution. Once passed through the filter paper with the solid precipitate was removed then left to dry. After it had been dried it was then weighed, and the mass of the precipitate was determined. Using stoichiometry one was able to determine the limiting reagent and the theoretical yield. Finally the percentage yield was calculated using the mass of the precipitate and the theoretical yield.