It is much, much有可能表示“... 得多”,后面加形容词比较级,如It is much bigger (than this one).
There is much, much表示“许多”,后面加不可数名词,如There is much water.
It is much heavier. much+比较级。 much 副词,----的多
There is much water on the floor. much+不可数名词。much 形容词,许多---