Question

Обчисліть масову частку кристалізаційної води в кристалогідратах : cocl2*6h20 cocl2*4h2o cocl2*h2o

Answer 1

Mr(CoCl2) = Ar(Co) + 2Ar(Cl) =  59 + 2 * 35.5 = 130

Mr(H2O) = 2Ar(H) + Ar(O) = 2 * 1 + 16 = 18

Mr(CoCl2 * 6H2O) = Mr = Mr(CoCl2) + 6Mr(H2O) = 130 + 6 * 18 = 238

w(H2O) = 6Mr(H2O) / Mr = 108 / 238 = 0.4538 = 45.38%

Mr(CoCl2 * 4H2O) = Mr = Mr(CoCl2) + 4Mr(H2O) = 130 + 4 * 18 = 202

w(H2O) = 4Mr(H2O) / Mr = 72 / 202 = 0.4538 = 0.3564 = 35.64%

Mr(CoCl2 * H2O) = Mr = Mr(CoCl2) + Mr(H2O) = 130 + 1 * 18 = 148

w(H2O) = Mr(H2O) / Mr = 18 / 148 = 0.1216 = 12.16%

CoCl2*6H20 -  45.38%

CoCl2*4H2O - 35.64%

CoCl2*H2O - 12.16%