Help/Advice Half hot receptacle
All cables are the same exact colors: Black and white.  Or sometimes, black white and red.  This means colors are almost meaningless.  There are three rules: 

a) bare and green are always ground;
b) White must be neutral if present, otherwise always-hot if present;  and
c) if the white wire is not neutral, it must be marked with tape or paint.  

This is an old style switch loop. It contains always-hot and switched-hot; no neutral.  Therefore the white must be always-hot and must be marked.  

The black and white joined together need to stay together.  These are "always-hot".  These two wires also go to the brass screw on the always-hot socket. 

The remaining black wire is "switched-hot", it's preferred to mark it with red tape, and it goes to the brass screw on the switched-hot socket.  

The remaining white is neutral, and goes to a silver screw.  

Note that the tab between the brass screws is removed.