can you add memory?
Seems not, per specs.
Memory: Your Choice:
2GB DDR3 (on-board, non-expandable)
4GB DDR3 (on-board, non-expandable)
Does it have ethernet RJ-45?
Yes it does, all Chromebooks have rj45. One of the standards that Google imposes on all manufacturers.
Does this have a card reader?
Does this have a SD card slot?