okay, so i began by finding the moles of ammonia in 1L,
first found moles in 100mL
c=n/v so n=cV
n=0.100M/0.1
= 0.01
then using henderson hasselbach,
pH=pKa+ log (NH4+/NH3)
9.5=9.25+log(NH4+/0.01)
0.25=log(NH4/0.01)
10^-0.25= (NH4/0.01)
NH4= 0.564 x 0.01
n of NH4 = 0.00565...