RDF VS XML

[Niyati]

Hi all,
I am new to RDF and have some questions regarding it.
I came to read about the advantages of RDF over XML which were:
1) Ordering of elements is important in XML while it is not in RDF.
2) Expressions used for Querying XML tree is more complex than they are
in RDF tree.

I would like to know whether these advantages are just because.. RDF
has a compulsory schema to follow and xml has not.

Is it the only advantage of using RDF over XML that it compells you to
follow some schema(of subject,predicate and object) thus making
retrieval easier?

I would be thankful to you if you can throw some light on it...


Thanks in advance
Niyati