c'est or il/elle est

[Sunshine]

I am confused as I have found the following sentences in a text book.

J'aime ma chambre parce qu'elle est grande

and

J'aime la techno parce que c'est tres utile.

Why do we use elle est in the first and not c'est and vice versa please.

[George Hunt]

There is a "rule" that you use a pronoun (il, elle etc) with an adjective and "ce" with a thing.

So: "elle est grande" but "c'est une chambre" (not "elle est une chambre" )

However rules are made to be broken and you can use "ce" with adjectives also.

In my mind I imagine "ce" to mean "it" and not to apply to a specific noun in the sentence except in a vague way.

But I may be mistaken to see it like that ..

By the way you could also have "J'aime la techno parce qu'elle est tres utile" and the meaning would be very similar.

[Robert]

'Ce' seems the better choice where an adverb is present:
Il est utile.
C'est très utile.

[George Hunt]

Whenever you have a pronoun you are immediately wondering what it refers to.

So "il est utile" makes me think "what particular thing is useful?"

It could be "elle est utile" and then I might look for some thing in the feminine gender that was recently mentioned , like a key ,perhaps or friendship.

(although "il" can also just be used for "it" as in "il fait beau" )