What mass of silver oxide, ag2o, is required to produce 25.0 g of silver sulfadiazine, agc10h9n4so2, from the reaction of silver oxide and sulfadiazine?

Step  one write  the chemical   equation  for  reaction
=  Ag2O  +  2(C10H10N4SO2)---> 2 ( AgC10H9N4SO2)

The   reacting  ratio  of  Ag2O  to  AgC10H9N4SO2  is  1:2  from   the  reaction  above
    
step  2;  find  the  number  of  moles  of  AgC10H9N4SO2
that is  mass/molar  mass
The  molar  mass  of  AgC10H9N4SO2  =  107.86  +(12 x10) + (1 x 9) +  (4 x  14) +32 +(16 x2) =356.86g/mol
moles  is  therefore=  25g/356.86g/mol=  0.07moles

by  use  of  mole  ratio  the  moles   of  Ag2O=  0.0702=0.035moles
mass  =  moles x  molar  mass
the  molar  mass  of  Ag2O=231.72 g/mol
mass  is therefore=  231.72g/mol  x  0.035moles= 8.11grams