Question

1. My mom’s chocolate chip cookie recipe calls for an 10 oz. bag of chocolate chips. If the recipe makes 26 cookies and the whole batch weighs 114 oz.

a. What is the mass percent of chocolate in a single cookie?

b. How many ppm and ppb of non-chocolate is in each cookie? (Assume I didn’t eat any chips while baking.)

Answer 1

1.a. Mass percent of chocolate in single cookie= (Mass of chocolate/Mass of batch)*100 [The chocolate composition will be uniform throughout the batch]

                                                                =(10/114)*100=8.77%

b) Non chocolate in each batch=114-10=104

PPM=(Non chocolate in each cookie/Mass of cookie)*10⁶=9.12*10⁵

PPB=(Non chocolate in each cookie/Mass of cookie)*10⁹=9.12*10⁸