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 be $2.363\times 10^{22} atoms$ .

8 0

3 years ago

Which statement best reflects a change in weather

Maurinko [17]

Option A. is the best answer

4 0

3 years ago

Read 2 more answers

How many atoms are in 12 moles of I. Check your significant figures.

ELEN [110]

Explanation:

7.2×1024 moleas

please mark as brilliant

5 0

2 years ago

What is the advantage of seeds that can be spread over a wide area?

Tema [17]

Answer:

I'm fairly sure it's D

Explanation:

If they're more spread out than they're roots in theory should have more space. Sorry if I'm wrong

6 0

3 years ago