Glad you asked...
The way to figure out percent purity you must take the mass of the product and divide that amount by the mass of the impure product then take that amount and multiply it by 100%. For more help click here http://www.onlinemathlearning.com/percen...
Then again, this answer might help you...
Percent Purity is equal to amount of substance divided by total amount of substrate multiplied by 100.Percent Purity = Amount of Substance / Total Amount of Substrate * 100

