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?
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
w of CuS=0.01/1.06*100=1% m of CuS=89*0.01=0.89g m of CU2S=88.11 g