Mr(H3PO4) = 1*3 + 31 + 16*4 = 98
Mr(Na2SO4) = 23*2 + 32 + 16*4 = 142
Mr(H2SiO3) = 1*2 + 28 + 16*3 =78
Mr(H3PO4) = 1*3 + 31 + 16*4 = 98
Mr(Na2SO4) = 23*2 + 32 + 16*4 = 142
Mr(H2SiO3) = 1*2 + 28 + 16*3 =78