def element_mass_fractions(compound, elements):
return [element_mass_fraction(compound, element)<EOL>for element in elements]<EOL>
Determine the mass fractions of a list of elements in a chemical compound.

:param compound: Formula and phase of a chemical compound, e.g.
  'Fe2O3[S1]'.
:param elements: List of elements, ['Si', 'O', 'Fe'].

:returns: Mass fractions.