hi these are the answers :)
Since the beaker was heated we can asume that only magnesium cloride is left in the beaker, therfore the difference between the beaker with magnesium chloride and the empty beaker give the mass of magnisium chloride:
Answer:
It should be 115.5 amu but you didnt type that as an answer choice so...
Explanation:
Bruh all you had to do was add oxygen and sulfur and subtract from the total to get your answer :D.