Question

How much chalcopyrite had to be mined to produce 100 pennies if reaction 1 had a percent yield of 64.00 % and all other reaction steps had yield of 100%?

Answer 1

`m_(CuFeS_2)=554.44gCuFeS_2`

Step-by-step explanation:

Hello,

During this process, the following chemical reactions are carried out:

`(1) 2 CuFeS_2 + 3 O_2 ---- > 2 CuS + 2 FeO + 2 SO_2\\(2) 2 FeO + SiO_2 ---- > 2 FeSiO_3\\ (3) 2 CuS ---- > Cu_2S + S\\(4) Cu_2S + S + O2 ----> 2 Cu + 2 SO_2\\`

Now, a typical penny, has about 3.0 g of copper, it means that 100 pennies have 300 g of copper, thus, we develop the following stoichiometric procedure to determine the sulfur that is consumed in the 4th reaction, because in the third one it is produced:

`n_(S)=300gCu*(1mol Cu)/(63.5gCu) *(1mol S)/(2molCu) =2.36molS`

Since the percent yield for the second, third and fourth chemical reactions is 100%, we now proceed to the third reaction to compute consumed cupric sulfide since it is produced in the first chemical reaction, thus:

`n_(CuS)=2.36molS*(2molCuS)/(1molS)= 4.72molCuS`

Finally, by using the first chemical reaction and the percent yield (represented by the by-moles relationship of cupric sulfide), one computes the required mass of chalcopyrite (
`CuFeS_2`) with a molecular mass of 183.54g/mol considering the first chemical reaction:

`m_(CuFeS_2)=4.72molCuS*(64mol CuS)/(100molCuS) *(2molCuFeS_2)/(2molCuS) *(183.54gCuFeS_2)/(1molCuFeS_2) \\m_(CuFeS_2)=554.44gCuFeS_2`

Best regards