  In a $\Lambda$CDM cosmology, galaxy formation is a globally inefficient
process: it is often the case that far fewer baryons are observed in galaxy
disks than expected from the cosmic baryon fraction. The location of these
"missing baryons" is unclear. By fitting halo profiles to the rotation curves
of galaxies in the SPARC data set, we measure the "missing baryon" mass for
individual late-type systems. Assuming that haloes initially accrete the
cosmological baryon fraction, we show that the maximum energy available from
supernovae is typically not enough to completely eject these "missing baryons"
from a halo, but it is often sufficient to heat them to the virial temperature.
The energy available from supernovae has the same scaling with galaxy mass as
the energy needed to heat or eject the "missing baryons", indicating that the
coupling efficiency of the feedback to the ISM may be constant with galaxy
virial mass. We further find that the energy available from supernova feedback
is always enough to convert a primordial cusp into a core and has magnitude
consistent with what is required to heat the "missing baryons" to the virial
temperature. Taking a census of the baryon content of galaxies with ${\rm
10^9<M_{vir}/M_{\odot}<10^{12}}$ reveals that $\sim86\%$ of baryons are likely
to be in a hot phase surrounding the galaxies and possibly observable in the
X-ray, $\sim7\%$ are in the form of cold gas, and $\sim7\%$ are in stars.
