You are in space and running out of water. You do have a great deal of magnesium carbonate pentahydrate. It is possible to extract the water from this. Determine the percent of water by mass in the hydrate magnesium carbonate pentahydrate (MgCO_3 middot 5H_2O). If your answer is 17%, enter 17, do not put in the percent sign. As an introduction to his class, Severus Snape teaches the first years at Hogwarts about hydrates. He begins with equations representing various dehydrations. Which of the following equations properly represents the dehydration of magnesium carbonate pentahydrate (MgCO_3 middot 5H_2O)?
MgCO_3 middot H_2O MgCO_3 + H_2O MgCO_3 middot 5H_2O
MgCO_3 + 5H_2O MgCO_3 middot 5H_2O MgCO_3 + H_2O
MgCO_3 middot 5H_2O MgCO_3 + 5H_2O