Answer: \(3.9\times 10^{23}\) molecules of \(Cu(NO_3)_2\)
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number \(6.023\times 10^{23}\) of particles.
To calculate the number of moles, we use the equation:
\(\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}\)
\(\text{Number of moles of} Cu(NO_3)_2=\frac{122g}{187.56 g/mol}=0.65\)
1 mole of \(Cu(NO_3)_2\) contains=\(6.022\times 10^{23}\) molecules of \(Cu(NO_3)_2\)
Thus 0.65 moles of \(Cu(NO_3)_2\) contains=\(\frac{6.022\times 10^{23}}{1}\times 0.65=3.9\times 10^{23}\) molecules of \(Cu(NO_3)_2\)
Thus there are \(3.9\times 10^{23}\) molecules of \(Cu(NO_3)_2\)