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:

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

Here, m is mass and M is molar mass.
Putting the values,

Now, in 1 mole of Cu there are
thus, in 0.03923 mol, number of Cu atoms will be:

Thus, number of atoms of Cu will be
.
Answer:
197 + (35.5×3) = 303.5
Explanation:
relative formula mass is the sum of the relative atomic masses of the atoms in the formula ( AuCl3 )
To solve this problem, the dilution equation (M1 x V1 = M2 X V2) must be used. The given values in the problem are M1= 12.0 M, V1= 30 mL, and M2= 0.160 M. To solve for V2,
V2=M1xV1/M2
V2= (12x30)/0.16
V2= 2,250 mL.
The correct answer is 2.25 L.
Answer: Therefore, the volume of a 0.155 M potassium hydroxide solution is 56.0 ml
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
According to the neutralization law,
where,
= molarity of
solution = 0.338 M
= volume of
solution = 25.7 ml
= molarity of
solution = 0.155 M
= volume of
solution = ?
= valency of
= 1
= valency of
= 1
Therefore, the volume of a 0.155 M potassium hydroxide solution is 56.0 ml