In Flask A, you reacted 5.10 g Mg with 0.447 mol HCl. In Flask B, you reacted 24.21 g Mg with 0.998 mol HCl. Which ballon will inflate the most?

Answer 1

These are two limiting reagent problems rolled into one. If you don't know how to do limiting reagent problems here is a link that will show you how to do them step by step. Post your work if you get stuck.
http://www.jiskha.com/science/chemistry/limiting_reagent_problem.html