Past exam of the chemistry course of the year 3 of the natural sciences course of the University of Cambridge / 2022 / Paper 4 / 64 / b / i / Solution

The coherent neutron scattering length density is atomic number density times scattering length:The density was converted to $\mathrm{g}{\mathrm{m}}^{-3}$ to match the molar mass in grams per mole, and $1{\mathrm{m}}^{-2}=10^{-20}{\mathring{\mathrm{A}}}^{-2}$.