Such or so?

Such is a determiner; so is an adverb. They often have the same meaning of ‘very’ or ‘to this degree’:

Those are such good chocolates.

Those chocolates are so good.

We use such + noun phrase     and     so + adjective or adverb phrase:

She is such a great cook.

Not: She is so great cook.

That was so unpleasant. (so + adjective)

Not: That was such unpleasant.

Why do you drive so fast? (so + adverb)

Not: Why do you drive such fast?

Compare

so + adjective	such + noun phrase
You’re so kind.	He’s such a kind person
It was so hot we couldn’t work.	November was such a cold month.

So but not such can also be used in front of much, many, little, few to add emphasis:

So much food was wasted every day.

Not: Such much food was wasted …

In those days there were so few doctors in our area.

Not: … there were such few doctors 

Typical errors

• We use such, not so, before a noun, even if there is an adjective before the noun:

They’re such snobs! They won’t speak to anyone else in the village.

Not: They’re so snobs …

Those are such cool shoes. Where did you get them?

Not: Those are so cool shoes.

• We use such, not so, before a noun phrase with the indefinite articlea/an:

This is such a wonderful kitchen!

Not: This is a so wonderful kitchen!

• We use so, not such, before adjectives:

Thank you. You’re so kind.

Not: You’re such kind.

• We use so, not such, before adverbs:

She always dresses so elegantly.

Not: She always dresses such elegantly.

              from English Grammar Today