You should write up a lab report on the composition of magnesium oxide (exercise 20).  Example 21 in the workbook shows the proper format for this (and future) lab reports.  The lab report should be written on a separate page (do not "fill in the blanks" on the sample lab report); it is preferable that you type your report although you may hand write your calculations if it is too difficult to format them properly.  The lab report will be turned in with your problem set when you take the quiz for this lesson.  Hybrid students: you may email your lab report to your instructor if you prefer.