what is difference between hip hop and rap?

You should have looked this up first but....

Hip Hop is a genre of music, Rap is a verb. People rap, the music that they make is Hip Hop. THEY ARE NOT TWO GENRES! A Rapper Raps, just like a Singer Sings. Do you call the music a singer makes Sing? Is it the genre of Sing? No it's not....neither is there a genre of Rap.

Rap is the lyrics in a hip hop song. Hip hop is a genre of music. A rapper raps in a song(hip hop) - rap is just the lyrics.

Hip Hop is a CULTURE

Rap is a SUB-GENRE of hip hop.

Afrika Bambatta already told us, the 5 pillars:

Rappin/emcee

Breakdance

Graffiti

DJing

Beatboxing

so, rap is just 1 of the 5 sub genres of hip hop.