Percent+Yield+and+Purity

= Percent Yield and Percent Purity: =

The yield is the amount of product you obtain from a reaction.
= Example: =

*Example:
== **The medical drug aspirin is made from salicylic acid. 1 mole of salicylic acid gives 1 mole of aspirin. Given that the chemical formular** for salicylic acid is C 7 H 6 O 3 and the chemical formula for aspirin is C 9 H 8 O 4. ==

So, the percent yield = 121.2 ÷ 130.5 × 100% = 92.9%
= = = = = Part 2 =

*3[[image:new.jpg]]
**（these two products are the same, but they have different percent purity, so their color look different)**

*Example:
== Chalk is almost pure calcium carbonate. We can work out its purity by measuring how much carbon dioxide is given off. 10 g of chalk was reacted with an excess of dilute hydrochloric acid. 2.128 liters of carbon dioxide gas was collected at standard temperature and pressure (STP). ==