\(a,Ba\left(OH\right)_2\\ PTK_{Ba\left(OH\right)_2}=137+16\cdot2+2=171\left(đvC\right)\\ b,CuSO_4\\ PTK_{CuSO_4}=64+32+16\cdot4=160\left(đvC\right)\\ c,Fe_2\left(SO_4\right)_3\\ PTK_{Fe_2\left(SO_4\right)_3}=56\cdot2+32\cdot3+12\cdot12=352\left(đvC\right)\)