Chemistry of Copper Production The mineral chalcopyrite (CuFeS2) is an important source of coppe

step 1 Let's look at a few equations for the production of copper. All right, so we have this mineral c

Chemistry of Copper Production The mineral chalcopyrite...

Chemistry of Copper Production The mineral chalcopyrite $\left(\mathrm{CuFeS}_{2}\right)$ is an important source of copper metal, though recovering the metal requires several chemical reactions that transform CuFeS $_{2}$ into $\mathrm{CuS}$, then $\mathrm{Cu}_{2} \mathrm{S}$, and finally $\mathrm{Cu}$ metal. The pennies minted in the United States between 1909 and 1982 weighed $3.11 \mathrm{g}$ and were $95 \%$ by mass copper. a. How much chalcopyrite had to be mined to produce one dollar's worth of these pennies? b. How much chalcopyrite had to be mined to produce one dollar's worth of the pennies if the first reaction had a percent yield of $85 \%$ and the second and third reactions had percent yields of essentially $100 \% ?$ c. How much chalcopyrite had to be mined to produce one dollar's worth of the pennies if each of the reactions proceeded with $85 \%$ yield?

Chemistry of Copper Production The mineral chalcopyrite $\left(\mathrm{CuFeS}_{2}\right)$ is an important source of copper metal, though recovering the metal requires several chemical reactions that transform CuFeS $_{2}$ into $\mathrm{CuS}$, then $\mathrm{Cu}_{2} \mathrm{S}$, and finally $\mathrm{Cu}$ metal. The pennies minted in the United States between 1909 and 1982 weighed $3.11 \mathrm{g}$ and were $95 \%$ by mass copper.
a. How much chalcopyrite had to be mined to produce one dollar's worth of these pennies?
b. How much chalcopyrite had to be mined to produce one dollar's worth of the pennies if the first reaction had a percent yield of $85 \%$ and the second and third reactions had percent yields of essentially $100 \% ?$
c. How much chalcopyrite had to be mined to produce one dollar's worth of the pennies if each of the reactions proceeded with $85 \%$ yield?

Key Concepts

Chemical Reaction Stoichiometry

Chemical reaction stoichiometry involves using balanced chemical equations to relate the quantities of reactants and products. This concept allows one to convert between masses and moles and predict how much product is formed from a given amount of reactants, which is essential in processes such as metal extraction.

Percent Yield

Percent yield compares the actual amount of product obtained from a reaction to the theoretical maximum amount predicted by stoichiometry. This concept is crucial for understanding the efficiency of chemical reactions, especially in industrial processes where incomplete reactions or side reactions may occur.

Cumulative Yield in Sequential Reactions

In multi-step chemical processes, the overall yield is determined by the product of the yields of individual steps. This cumulative effect means that even slightly suboptimal yields in each step can significantly reduce the final amount of product, highlighting the importance of optimizing every stage in a production sequence.

Mineral Composition and Extraction

Understanding the composition of a mineral, such as the elemental percentages within chalcopyrite, is essential for accurately converting mined material into a desired product. This concept bridges the gap between raw material processing and chemical conversion, playing a key role in determining the efficiency and feasibility of metal extraction processes.

Transcript

00:01 Let's look at a few equations for the production of copper.

00:03 All right, so we have this mineral called chakal pyrite, and it has the formula c -u -f -e -s -2.

00:18 And this mineral is a source of copper metal.

00:23 And the way this process is done is chakopyrite is converted to copper sulfate, the us and then copper to sulfate and then finally copper.

00:47 And we wanna know how much of this stuff, the chalko -pyrite, has to be mined for some pennies.

00:55 So let's say a penny is 3 .11 grams and it's 95 % copper.

01:15 How much chalco -pirite do we need for a hundred pennies? 100 pennies here.

01:26 Alright so first off, we're gonna have to find out how much of each penny is copper.

01:33 So we'll take our 3 .11 and multiply that by 95 % so this gives us 2 .95 grams of copper per penny all right so we want to know how much is in a hundred so we'll multiply this number by 100 at 295 grams so then we need to find out how many moles of copper we have here so we have two hundred ninety five grams over the atomic mass of copper which is 63 .56 grams per mole and this will give us 4 .64 and so this is how many moles of copper that we need to make a hundred pennies so if it takes 4 .64 moles of copper it'll also take 4 .64 moles of chalcopyrite.

02:59 So if we find the atomic mass of this chalcopyrite and we multiply it by the number of moles, we'll get how much chalcopirite we need.

03:13 So we'll go and take our 4 .64, multiply that by the atomic mass of chalco pyrite.

03:23 It's going to be 183.

03:28 0 .53 and then i'll give us 851 .58 grams chalco -pyrite.

03:42 This is how much we need to make 100 pennies.

03:48 So we just found out we need 4 .64 moles of chalcopyrite to make 100 pennies.

03:56 So let's say that this reality reaction, the chalcopyrite to this copper sulfate proceeds at 85 % efficiency.

04:09 But these other two are 100.

04:11 So that one's going to be 100 and that one's going to be 100.

04:17 How many moles of chalcopyrite do we need if this proceeds at 85%.

04:24 So we don't have to worry about these since these are 100 % efficient.

04:30 So for this one we'll take our 4 .64 moles and we have to work backwards here so we're 4 .64 moles of copper and then we'll go here and here and then this is where the conversion takes place.

04:44 So we have 4 .64 moles and for this question it'll be this copper sulfate so we have 4 .64 moles of that and we're going to multiply this by 100 over 85.

05:03 And this will give us 85 % efficiency...

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