What is the density of the marble when the mass = 10g

The density of marble is between 2.6 and 2.8 grams per cm³ .

Density doesn't depend on how much mass or volume of it you have.
The density of a chip of it is the same as the density of a truckload of it.

The mass has escaped into a gas which you can not see so the law stays true.

Ithink this is what you meant. the temperature at which a liquid begins to boil is called the boiling point. the boiling point of water is 212°f or 100°c.  and at that point will start to turn into steam (gas)