During an investigation a scientist heated 27 g of mercuric oxide till it decomposed to leave a dry product. the total mass of the product formed was 25 g. does the law of conservation of mass hold true in this case? use complete sentences to justify your answer based on numerical calculations.

Even though two grams of the mercuric oxide seemed to disappear or vanish, the law of conversation of mass still holding true. Mercuric oxide, when heated, forms a gas of mercury and oxygen. During the investigation, some gas could have escaped or evaporated during the experiment! 

I am going to have to go with Mysterious,
Good Luck!!