How does the genre of the novel (gothic) have an influence on the language, setting and atmosphere?i also got to link it to why chapter 5 is...

I have no clue from what you've given which Gothic novel
you might be reading; however, there are some common elements among most novels of this
genre.  You ask about three of them, so here goes:

Language
- The language is typically dark and ominous, as if something bad is always about to
happen.  There may be elements of mystery and suspense, often heightened by the setting
(mentioned below).  There is not much joy or delight in a truly Gothic novel.  Think
Edgar Allan Poe.

Setting - Marked with death and decay;
morbid and dark; foreboding and frightening.  The buildings are generally tall and show
signs of decay and "oldness"--and of course they have the expected winding staircases,
attics, secret passageways, and basements/dungeons. Cemeteries and other kind of
"creepy" places are typical stops in a Gothic
novel.

Atmosphere - This is created by the both of the
other things just mentioned.  How does an author create a particular atmosphere but by
his words and his settings.  Add characters and plot (which you did not mention) and
that's all there is.

A completely Gothic novel would be a
pretty dismal read, I think.  Instead, we find Gothic elements throughout many works
over the years.