when a substance is boiled what happens to the mass?
The particles in a substance stay the same when it changes state-only their closeness, arrangement or motion change. This means that the mass of the substance stays the same. For example, 10 g of water boils to form 10 g of steam, or freezes to form 10 g of ice. This is called conservation of mass. 1  1. 2  2. 3  3.