An idiot needs your help, Pianostreet!

[perprocrastinate]

I don't know how I haven't resolved this until now.

I can't tell the difference between a slur and a tie. They both look similar, if not the same (?).

So basically Wikipedia explains a slur as 'implying legato articulation between a group of notes' and a tie as 'connecting two notes of the same pitch indicating that they are to be played as a single note with a duration equal to the sum of the individual notes' note values.'

Can a slur be applied to notes of the same pitch?

[mikeowski]

No, something like that might be done with a tenuto marking or plain old 'legato' written next to it or at the beginning of the piece. Or a bow over the whole phrase might indicate it aswell.
You just couldn't tell the difference between a slur connecting the same pitches and a tie because, yes, they look exactly the same.

[sucom]

If you put a slur across two different notes it is played as a slur.  However, if you put a slur across two notes which are exactly the same pitch, the slur becomes a tie.  The only difference between a slur and a tie is the pitch of the notes.

However, if a slur is positioned over two notes which are exactly the same in pitch but each note also has a staccato dot or a _ (tenuto) mark, then the slur is NOT a tie.  Adding the staccato dots means the notes should be played detached, ie. not quite as short as regular staccato.  Adding tenuto marks to the two notes means that both notes are detached but with a very, very slight, subtle emphasis on each note.