Mr(Cu(OH)2) = 98
w(Cu) = 64/98 *100 = 65,31

Mr(NaH) = 24
w(Na) = 23/24 *100 = 95,83

Mr(H3PO3) = 82
w(H) = 3/82 * 100 = 3,66
w(P) = 31/82 * 100 = 37,8
w(O) = 48/82 * 100 = 58,54

Mr(HClO4) = 100,5
w(O) = 64/100,5 * 100 = 63,68
w(Cl) = 35,5/100,5 * 100 = 35,32

Mr(H2SiO3) = 78
w(Si) = 28/78 * 100 = 35,9
w(O) = 48/78 * 100 = 61,54

Mr(Ag2O) = 232
Mr(Ag) = 216/232 * 100 = 93,1