Problem: Commercial brass, an alloy of Zn and Cu, reacts with hydrochloric acid as follows:Zn (s) + 2 HCl (aq) → ZnCl 2 (aq) + H2 (g) (Cu does not react with HCl.)When 0.5065 g of a certain brass alloy is reacted with excess HCl, 0.0985 g ZnCl2 is eventually isolated. How could this result be checked without changing the above procedure?

FREE Expert Solution

We're being asked to determine how could the result of the reaction be checked without changing the given procedure. We're given the following balanced reaction:

Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) (Cu does not react with HCl.)


First, we need to calculate the amount of zinc needed to produce 0.0985 g ZnCl2.

From the balanced reaction:  1 mole of Zn produces 1 mole of ZnCl2.

mass ZnCl2 (molar mass ZnCl2) → moles ZnCl2 (mole-to-mole comparison) → moles Zn (molar mass Zn) → mass Zn

molar mass of Zn = 65.39 g/mol

molar mass of ZnCl2:

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Problem Details

Commercial brass, an alloy of Zn and Cu, reacts with hydrochloric acid as follows:

Zn (s) + 2 HCl (aq) → ZnCl 2 (aq) + H2 (g) (Cu does not react with HCl.)

When 0.5065 g of a certain brass alloy is reacted with excess HCl, 0.0985 g ZnCl2 is eventually isolated. How could this result be checked without changing the above procedure?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Stoichiometry concept. You can view video lessons to learn Stoichiometry. Or if you need more Stoichiometry practice, you can also practice Stoichiometry practice problems.

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Based on our data, we think this problem is relevant for Professor Pelton's class at UMN.

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Our data indicates that this problem or a close variation was asked in Chemistry: An Atoms First Approach - Zumdahl Atoms 1st 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl Atoms 1st 2nd Edition practice problems.