Question

How many moles of H2 can formed from 7.5 moles of SrH2?

Answer 1

Doesn't this depend somewhat upon what the SrH2 reacts with?

The question is a little confusing to me. If you ask how many moles H2 are in 7.5 mols SrH2 then it is
7.5 moles SrH2 x (1 mol H2/1 mol SrH2) = 7.5 mols H2 but if I react that SrH2 with water like this SrH2 + 2H2O ==> Sr(OH)2 + 2H2 then I can get 4 moles H2.