What is EAN of Cu in $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}$ ?

Calculate the number of unit cells in 10.8 g metal $\left(\varrho a^3=7.2 \times 10^{-22} \mathrm{~g}\right)$

Calculate van't Hoff factor of 0.2 m aquesous solution of an electrolyte if it freezes at $-$0.7 K $\left[\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$

What is momentum of a microscopic particle having de Broglie's wavelength 6.0 A?

$$\left(\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}\right)$$