Final answer:
The amount of CuFeS₂ required to produce 100 pennies cannot be precisely calculated without additional information on the process and the amount of copper needed per penny. However, the concept of percent yield is crucial in adjusting the theoretical yield based on the actual efficiency of the chemical reactions involved.
Step-by-step explanation:
To determine how much CuFeS₂ (chalcopyrite) is required to produce 100 pennies, we must understand the process that involves multiple steps of chemical reactions with varying percent yields. Since Reaction 1 is at a 100% yield, we only need to consider the reduced efficiency of steps 3 and 4, which are at 80% yield.
Firstly, we need to understand the chemical reactions that are taking place:
1. CuFeS₂ is used to produce Cu.
2. Cu is processed further to create copper metal for pennies.
The fact that reaction steps 3 and 4 are at 80% yield means we have a decrease in efficiency and output relative to the theoretical yield.
To perform the calculation, we need to use the molar masses provided for CuSO₄ and Cu. The stoichiometric calculations are based on the balanced equation that shows a 1:1 relationship among the reactants and products. We calculate the theoretical yield of Cu from CuSO₄, and then adjust for the percent yield in later steps.
Using the percent yield formula:
Percent yield = (Actual yield / Theoretical yield) × 100%
If we know the quantity of copper (in moles or grams) required for 100 pennies, we adjust the theoretical yield of the reaction by the percent yield to find the actual amount of CuFeS₂ needed, considering the 80% yield in the final steps (3 and 4). However, since the actual amount of copper needed for 100 pennies is not provided, and we do not know the exact processing steps transforming CuFeS₂ into pure Cu, precise calculation is not possible from the given information. If we were provided more details on the process and reaction steps, a detailed calculation could then be made to find the exact amount of CuFeS₂ needed.