Chemical substances how to make?

How to make a chocolate CADBURY DAIRY MILK?

IF YOU EAT this chocolate a small piece or a very big piece in any where either in delhi or kolkata there will be no difference in taste.that means the ratio of milk, water,sugar and other things is remain same in its small piece or a very big piece.

In such a way if we analyse the substance WATER where ever you take it from either ganga river or yamuna river or any other river in any thing either in glass or a big jar it's taste do not vary because of same ratio of hydrogen and oxygen.

So In such a way chemical substances is made so that there properties do not vary with place and amount.