GRE Subject Test: Chemistry : Other Statistics

Example Questions

Example Question #11 : Analytical Chemistry

Determine the percentage yield if the expected yield of  in the above reaction is 40.911 grams but the actual yield is 35.322 grams.

Explanation:

In chemistry, percentage yield is a term used to quantify the efficiency of a chemical reaction. In order to calculate this quantity, the value for the actual yield and theoretical yield is needed. The actual yield is the amount of product obtained during a chemical reaction. The theoretical yield is the maximum amount of product possible to be obtain by a chemical reaction which is based on the amount of reactants used. Below is the formula needed to calculate the percentage yield.

Example Question #11 : Analytical Chemistry

0.0031 moles of  was reacted with 0.0071 moles of  giving an actual yield of 0.1733 grams of . What is the percent yield of this reaction?

Explanation:

is the limiting reactant because based on the equation,  and  react in a 1:1 mole ratio. However, there is 0.0040 moles more of  than  present. Therefore the amount of  produced is limited by the amount of  present in the reaction. Based on the equation, for every 1 mole of  reacted, 1 mole of  was produced:

Therefore,

Example Question #11 : Analytical Chemistry

Determine the percentage yield if the expected yield of  in the above reaction is 1.2124 grams but the actual yield is 0.9749 grams.