  We present calculations of the thermal and electric linear response in
graphene, including disorder in the self-consistent t-matrix approximation. For
strong impurity scattering, near the unitary limit, the formation of a band of
impurity states near the Fermi level leads to that Mott's relation holds at low
temperature. For higher temperatures, there are strong deviations due to the
linear density of states. The low-temperature thermopower is proportional to
the inverse of the impurity potential and the inverse of the impurity density.
Information about impurity scattering in graphene can be extracted from the
thermopower, either measured directly, or extracted via Mott's relation from
the electron-density dependence of the electric conductivity.
