Unit+4+-+Percent+Yield

** In chemistry not every reaction goes to completion that why we calculate % yeild. Reaction occur when reactants collide with eachother. when the reatants are concentrated they react quickly but after they decrease through the course of the reaction they collide less often. It will take an infinity amount of time for the reactiants to completely collide and react. We calculate % yield as a means to learn ho w well a certian reation created the desired product in a given amount of time.
 * Percent yield

% Yield - the ratio of what we got to what we expected

% Yield = actual yeild / theoretical yeild x 100

Ex.) When potassium Chromate(K2CrO4) is added to a solution of AgNO3 containing 0.500g of the substance, solid silver chromate is formed. - determine the theoretical yeild - if only 0.455g of silver chrmate was recovered, what is the % yield?

K2Cr04 + 2AgNO3 === Ag2Cr04 + 3KNO3

0.500g x 1mol AgNO3/169.97g(AgNO3) x 1molAg2CrO4/2mole(AgNO3) x 324.8g(Ag2CrO4)/1mol(Ag2CrO4) = 0.488g Ag2CrO4

0.455/0.488 x 100 = 93%