What occurs when gas molecules escape from the surface of a open container of liquid?

Well they evaperate into the air were the become percipitating and fall back on to the earth eventually getting sucked back into the air again

Hydrogen sulfide = hidrogen + sulfur

       6.500 g                      

a)                             0.384 g   +    x

=> 6.500 = 0.384 + x => x = 6.500 - 0.384 = 6.116 g

6.116 g of sulfur must be obtained

b) this experiment demonstrate the conservation of mass.

c) Dalton's atomic model states that the atoms cannot be created, split or be destroyed, and so in a chemical reaction the atoms rearrange but the number of each type of atoms remain constant, so the mass of each type of atoms and the total mass remain constant.