Вычислить массу хрома, полученного методом алюминотермии Сг2 О3 из оксида хрома (III)760 г, содержащего 80% - ную смесь.

1) Cu₂S

Mr(Cu₂S) = 64*2 + 32*1 = 160

w(Cu) = 2Ar(Cu)/Mr(Cu₂S) = 128/160 = 0,8 = 80%

w(S) = 100%-80% = 20%

2) Cu₂O

Mr(Cu₂O) = 64*2+16 = 144

w(Cu) = 2Ar(Cu)/Mr(Cu₂O) = 128/144 = 0,889 = 88,9%

w(O) = 2Ar(O)/Mr(Cu₂O) = 16/144 = 0,111 = 11,1%

3) CuFeS₂

Mr(CuFeS₂) = Ar(Cu) + Ar(Fe) + 2Ar(S) = 64 + 54 + 64 = 184

w(Cu) = Ar(Cu)/Mr(CuFeS₂) = 64/184 = 0,3478 = 34,78%

w(Fe) = Ar(Fe)/Mr(CuFeS₂) = 56/184 = 0,3043 = 30,43%

w(S) = 100% - 34,78% - 30,43% = 34,79%

4) Cu₂So₄

Mr(Cu₂SO₄) = 2Ar(Cu) + Ar(S) + 4Ar(O) = 64*2 + 32 + 16*4 =  223

w(Cu) = 2Ar(Cu)/Mr(Cu₂SO₄) = 127/223*100 = 57%

w(S) = 2Ar(S)/Mr(Cu₂SO₄) = 32/223*100 = 14%

w(O) = 4Ar(O)/Mr(Cu₂SO₄) = 64/223*100 = 29%

5) Cu(NO₃)₂

Mr(Cu(NO₃)₂) = Ar(Cu) + 2Ar(N) + 6Ar(O) = 64 + 28 + 96 = 188

w(Cu) = Ar(Cu)/Mr(Cu(NO₃)₂) = 64/188*100 = 34%

w(N) = 2Ar(N)/Mr(Cu(NO₃)₂) = 28/188*100 = 15%

w(O) = 6Ar(O)/Mr(Cu(NO₃)₂) = 96/188*100 = 51%