Is this mold in my apartment?
Mold and mildew are both fungus growths but former is usually a black or greenish color whilst the mildew is typically a more white or light gray in color. A mildew could also appear to be fuzzy.

Mildew is easy to clean up using a readily available cleaner and a scrub brush. I would suggest that you experiment to see of those white splotches are able to be scrubbed up and if so then let the maintenance folks know that it should be removed. 

In the other hand these white patches could be the residue of some type of foam based carpet padding that stuck to the wood and stayed behind when the old carpet and padding was ripped out. If this is the case then it should be possible to remove most of it using a scraper or putty knife.