  We present Chandra X-ray observations of the young supernova remnant (SNR)
0509-67.5 in the Large Magellanic Cloud (LMC), believed to be the product of a
Type Ia supernova (SN Ia). The remnant is very round in shape, with a distinct
clumpy shell-like structure. Our Chandra data reveal the remnant to be rich in
silicon, sulfur, and iron. The yields of our fits to the global spectrum
confirm that 0509-67.5 is the remnant of an SN Ia and show a clear preference
for delayed detonation explosion models for SNe Ia. We study the spectrum of
the single brightest isolated knot in the remnant and find that it is enhanced
in iron by a factor of roughly two relative to the global remnant abundances.
This feature, along with similar knots seen in Tycho's SNR, argues for the
presence of modest small-scale composition inhomogeneities in SNe Ia. The
presence of both Si and Fe, with abundance ratios that vary from knot to knot,
indicates that these came from the transition region between the Si- and
Fe-rich zones in the exploded star, possibly as a result of energy input to the
ejecta at late times due to the radioactive decay of 56Ni and 56Co. Two cases
for the continuum emission from the global spectrum were modeled: one where the
continuum is dominated by hydrogen thermal bremsstrahlung radiation; another
where the continuum arises from non-thermal synchrotron radiation. The former
case requires a relatively large value for the ambient density (~1 cm^-3).
Another estimate of the ambient density comes from using the shell structure of
the remnant in the context of dynamical models. This requires a much lower
value for the density (<0.05 cm^-3) which is more consistent with other
evidence known about 0509-67.5. We therefore conclude that the bulk of the
continuum emission from 0509-67.5 has a non-thermal origin.
