Answer:
The answer to your question is: Â 4.9 g of BaSO4
Explanation:
Data
MgSO4 = 2.5 g
Ba(NO3)2 = excess reactant
BaSO4 = ?
Reaction
         MgSO4  +   Ba(NO3)2    ⇒   BaSO4  +   Mg(NO3)2
MW MgSO4 = 24 + 32 + 64
          = 120 g
MW BaSO4 = 137 + 32 + 64
          = 233 g
         120 g of MgSO4 ------------------  233g of BaSO4
         2.5 g           ------------------  x
         x = 4.9 g of BaSO4