The concentration of the sample in 100cm^3 is: 0.006525 mol/dm^3.
Calculate the concentration and number of moles in the 250 cm^3.
My calculations:
Concentration:
0.25/0.1 = 2.5
0.006525/2.5=0.00261 mol/dm^3
Number of moles:
0.00261 x 0.25 = 0.0006525
Is it right?