been on this for a while

A student sands the surface of a 6 cm strip of Mg metal and places it into a crucible. The crucible and Mg are massed, placed over a Bunsen bumer, and heated strongly for 10 minutes. After cooling, the final mass of the crucible and combustion product are taken. The following data are collected: 35.6439 g Mass of crucible and Mg before heating Mass of crucible and combustion product after heating 37.8901 g a. Explain how the experimental evidence helps the student confirm that a new compound had been made and that a chemical change occurred? (3 pts.)