Đáp án:
$a/$
$r=0,135nm=0,135.10^{-7}cm$
$V_{NT}=\frac{4\pi}{3}.r^{3}=\frac{4\pi}{3}.(0,325.10^{-7})^{3}=1,03.10^{-23}$
$m_{Zn}=65.u=65.1,6605.10^{-24}=1,08.10^{-22}$
$D=\frac{1,08.10^{-22}}{1,03.10^{-23}}=10,47g/cm^{3}$
$b/$
$V_{NT}=\frac{4\pi}{3}.r^{3}=\frac{4\pi}{3}.(2.10.10^{-13})^{3}=3,35.10^{-38}$
$m_{Zn}=65.u=65.1,6605.10^{-24}=1,08.10^{-22}$
$D=\frac{1,08.10^{-22}}{3,35.10^{-38}}=3,22.10^{15}g/cm^{3}$
