  We present a 1.42 square degree mosaic of diffuse X-ray emission in the Great
Nebula in Carina from the Chandra X-ray Observatory Advanced CCD Imaging
Spectrometer camera. After removing >14,000 X-ray point sources from the field,
we smooth the remaining unresolved emission, tessellate it into segments of
similar apparent surface brightness, and perform X-ray spectral fitting on
those tessellates to infer the intrinsic properties of the X-ray-emitting
plasma. By modeling faint resolved point sources, we estimate the contribution
to the extended X-ray emission from unresolved point sources and show that the
vast majority of Carina's unresolved X-ray emission is truly diffuse. Line-like
correlated residuals in the X-ray spectral fits suggest that substantial X-ray
emission is generated by charge exchange at the interfaces between Carina's
hot, rarefied plasma and its many cold neutral pillars, ridges, and clumps.
