Question #13389

An ore sample contains 11% impurity in additon to a mix of CuS and Cu2S. Heating 100g of the mix produces 75.4g of copper metal with a purity of 89.5%. What is weight 5 of CuS and Cu2S in the ore?

Expert's answer

75.4* 0.895=67.483 - it is the mass of pure copper

mass of S in sample is

100-67.483-100*0.11=21.517

n of S= 21.517/32=0.6724 moles

n of Cu

=67.483/63.5=1.06 moles

64* (1.06 - x) + 32*(0.64-x) + 64*2*x+ 32*x =

21.517+67.483

67.84-64x+20.48-32x+128x+32x=89

64x=0.68

x=0.01

w of CuS=0.01/1.06*100=1%

m of CuS=89*0.01=0.89g

m of

CU2S=88.11 g

mass of S in sample is

100-67.483-100*0.11=21.517

n of S= 21.517/32=0.6724 moles

n of Cu

=67.483/63.5=1.06 moles

64* (1.06 - x) + 32*(0.64-x) + 64*2*x+ 32*x =

21.517+67.483

67.84-64x+20.48-32x+128x+32x=89

64x=0.68

x=0.01

w of CuS=0.01/1.06*100=1%

m of CuS=89*0.01=0.89g

m of

CU2S=88.11 g

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