Lab: All Mixed Up

I was absent this day.  The agenda was:

            HW:  p. 44-45 #14-19

1.             DWU #2:

% composition (by mass)  = (mass of component / mass of sample) x 100

You combined 25.2 grams of sand, 29.2 grams of salt, and 49.2 grams of dirt in a bucket.  What is the percent composition by mass of each substance?

2.             Check HW and go over

3.             Lab:  All Mixed Up