The key difference between percent yield and percent recovery is that percent yield is calculated as a ratio between actual yield and theoretical yield whereas percent recovery is calculated as the ratio between the pure compound and initial compound.
Percent recovery computes the percentage of an original substance that is recovered after a chemical reaction is completed. These mainly include purification reactions. It also determines their efficiency.
Percent recovery = amount of substance you actually collected / amount of substance you were supposed to collect, as a percent. So another way of putting it: Percent Recovery = (pure/impure) x 100. Let's say you had 10.0g of impure material and after recrystallization you collected 7.0 g of dry pure material.
Actual yield is what you actually get in a chemical reaction. Percent yield is a comparison of the actual yield with the theoretical yield.
The recovery for accepted range in analytical chemistry is 70-120%.
Think of percent yield as a grade for the experiment: 90 is great, 70-80 very good, 50-70 good, 40-50 acceptable, 20-40 poor, 5-20 very poor, etc.
Usually a reaction is given a maximum percentage yield; as the name suggests, this is the highest percentage of theoretical product that can practically be obtained. A reaction yield of 90% of the theoretical possible would be considered excellent. 80% would be very good. Even a yield of 50% is considered adequate.
Calculating Recovery Rate
Once a target group is identified, add up how much money was extended to it over the given time period and then add up the total sum paid back by that group. Next, divide the total payment amount by the total amount of debt. The result is the recovery rate.
If you use too much solvent, less of the compound you're trying to purify recrystallizes (more remains in solution), and you'll get a low percent recovery (no impact on purity). ... If you use too little solvent, not all of your crystals will dissolve in the hot solvent, and they will retain some impurities.
The actual yield is the amount of product that is actually formed when the reaction is carried out in the laboratory. ... However, percent yields greater than 100% are possible if the measured product of the reaction contains impurities that cause its mass to be greater than it actually would be if the product was pure.