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Romashka [77]
3 years ago
12

How many cu atoms are present in a piece of sterlingsilver jewelry weighing 33.24 g ? (sterling silver is a silver–copper alloy

containing 92.5% ag by mass.)?
Chemistry
1 answer:
emmasim [6.3K]3 years ago
8 0

The mass of piece of sterling silver jewelry is 33.24 g. It contains 92.5% silver Ag by mass. Since, sterling silver is an alloy of Ag-Cu thus, percentage of Cu will be:

% Cu=100-92.5=7.5%

Thus, mass of copper will be:

m_{Cu}=\frac{7.5}{100}\times 33.24 g=2.493 g

Molar mass of Cu is 63.546 g/mol, thus, number of moles of Cu can be calculated as follows:

n=\frac{m}{M}

Here, m is mass and M is molar mass.

Putting the values,

n=\frac{2.493 g}{63.546 g/mol}=0.03923 mol

Now, in 1 mole of Cu there are 6.303\times 10^{23}atoms thus, in 0.03923 mol, number of Cu atoms will be:

0.03923 mol\times 6.303\times 10^{23}atoms=2.363\times 10^{22} atoms

Thus, number of atoms of Cu will be2.363\times 10^{22} atoms.


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When 6.0 mol Al react with 13 mol HCl, what is the limiting reactant, and how many moles of H2 can be formed?
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For the second part, you have to make the same procedure, make a conversion factor that will cancel the mol of HCL and for that you need to use the 6 mol HCL from your equation, and at the numerator you can put the 3 mol of H2 from the equation so that you can find the number of moles of H2 that will be produced.

13 mol HCL x 3 mol H2/6 mol HCL = 6.5 mol H2

As it can be seen, HCL produces the less amount of H2 moles. Therefore, the reaction CANNOT produce more than 6.5 mol H2, in that case 6.5 mol will be the maximum number of moles that will be produced at the end because HCL does not have enough to produce more than 6.5 mol.

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In a particular titration experiment a 30.0 ml sample of an unknown hcl solution required 25.0 ml of 0.200 m naoh for the end po
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The balanced equation for the acid base reaction is as follows
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stoichiometry of NaOH to HCl is 1:1
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concentration of HCl is 0.167 M
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3 years ago
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