AS chemistry homework help!!!!?

procedure is correct for each, but not some of the arithmetic, and atomic m Ba = 137.34 so 2.47g = 0.01798 mol. This number of moles of H2 occupies 0.01798 x 24 = 0.4315 dm3 at rtp. Concentration of the Ba(OH)2 is 0.01798/0.25 =0.0719 mol dm-3