Question

If you need to produce 3.50 kg of copper metal from a contaminated sample of reclaimed copper wiring, which is 68.3% copper, how many kg of reclaimed copper wiring would you need to buy if your percent yield at each step is 90%? Assume that you will isolate the copper wiring by going through the steps in this lab. Be sure to show all stoichiometry used. There are 7 steps.

Answer 1

Answer -

Mass of Copper metal to be produced = 3.50 kg

Copper % in reclaimed copper wiring = 68.3 %

Percentage yield at each step = 90 %

Number of steps = 7

Mass of reclaimed copper wiring needed = ?

Let us assume that mass of reclaimed copper wiring need is M

now, Mass % of Cu in reclaimed wiring = 68.3 %

So, mass of Cu in M = 0.683* M

There are 7 steps -

So,

Step 1 - Mass of Cu obtained = 90% of 0.683 * M = 0.6147 * M

Step 2 - Mass of Cu obtained = 90% of 0.6147 * M = 0.55323 * M

Step 3 - Mass of Cu obtained = 90% of 0.55323 * M = 0.497907 * M

Step 4 - Mass of Cu obtained = 90% of 0.497907 * M = 0.4481163 * M

Step 5 - Mass of Cu obtained = 90% of 0.4481163 * M = 0.40330467 * M

Step 6 - Mass of Cu obtained = 90% of 0.40330467 * M = 0.362974203 * M

Step 7 - Mass of Cu obtained = 90% of 0.362974203 * M = 0.3266767827 * M

So,

Mass of Cu Obtained = 0.3266767827 * M

M = Mass of Cu Obtained / 0.3266767827

M = 3.50 kg / 0.3266767827

M = 10.7139539305 kg or 10.714 kg approx

So The mass of reclaimed copper wiring needed is 10.714 kg approx. [ANSWER]