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Author Topic: please help solve this. no one else in the class could. neither could teachers.  (Read 1228 times)

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meggles

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1.) You have been asked to produce 7.8 g isotopically labeled copper sulfate pentahydrate. You start with copper metal that contains 95 % (w/w) 67Cu, which has a half-life of 61.83 hours and 83 % (w/v) sulfuric acid. Calculate the charges of the reactants, if the isolated yield reported in the literature was 91.3 % of theory. What is the copper metal contaminated with?
2.)What is the weight of 67Cu in your product, if synthesis and purification took 2 days?
3.)In a second step, you heat all of your product to 650 °C, where copper-(II)-sulfate decomposes to copper-(II)-oxide and sulfur trioxide. How many liters of sulfur trioxide do you release under standard conditions. Assuming the latter reaction has an equilibrium constant of 2.4 x 108, what is the expected yield of copper-(II)-oxide if this step took 16 hours?
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Arkcon

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1.) You have been asked to produce 7.8 g isotopically labeled copper sulfate pentahydrate. You start with copper metal that contains 95 % (w/w) 67Cu, which has a half-life of 61.83 hours and 83 % (w/v) sulfuric acid. Calculate the charges of the reactants, if the isolated yield reported in the literature was 91.3 % of theory. What is the copper metal contaminated with?

This is a tough question, only because its hard to understand why its asking what it seems to be asking.  Radioactive isotopes of copper have the same charge as other isotopes.  So the charges are the same.  I suppose its contaminated with other isotopes and decay products, but I don't know which ones.

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2.)What is the weight of 67Cu in your product, if synthesis and purification took 2 days?

OK, isotopes decay by first order reactions.  There's a formula in your book to plug in the half-life you were given.

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3.)In a second step, you heat all of your product to 650 °C, where copper-(II)-sulfate decomposes to copper-(II)-oxide and sulfur trioxide. How many liters of sulfur trioxide do you release under standard conditions. Assuming the latter reaction has an equilibrium constant of 2.4 x 108, what is the expected yield of copper-(II)-oxide if this step took 16 hours?

You can start to solve this one with a balanced chemical equation, so you can relate grams of reactant, to grams of product.
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That all depends on how reasonable we're all willing to be.  I just want my friends back, except for Cartman, you can keep him.

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