Glad you asked...
Add up how much you have left and divide that by what you started with. Take that number which should be a decimal point and multiply it by 100 to get a percentage of what was recovered.
kristina.ayers     How-To Expert
Then again, this answer might help you...
In chemistry, you can calculate percent recovery by using this simple formula: percent recovery = (mass of the substance in pure form/mass of what you have) X 100.
jsmith     How-To Expert
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