дано m(CL2) = 17.75 g --------------------- m(FeCL2)-? 17.75 X 2Fe+3CL2-->2FeCL3 M(CL2) = 71 g/mol , M(FeCL3) = 162.5 g/mol 3*71 2*162.5 X = 17.75 * 325 / 213 = 27.08 g ответ 27.08 г
4. дано m(H3PO4) =19.6 g NaOH --------------------- m(Na3PO4)-? 19.6 X H3PO4+3NaOH-->Na3PO4+3H2O 98 3*40 M(H3PO4) = 98 g/mol M(NaOН) =40 g/mol X = 19.6*120 / 98 = 24 g ответ 24 г
5. дано m(HCL)= 9.125 g +Fe ---------------------------- m(FeCL2)-? 9.125 X 2HCL+Fe-->FeCL2+H2 M(HCL)= 36.5 g/mol M(FeCL2) =127 g/mol 2*36.5 127 X =9.125*127 / 73 = 15.875 g ответ 15.875 г