Josie observed that when water is boiled in an open beaker it completely disappears, leaving the beaker dry. what can josie conclude? a) mass is created in this experiment. b) mass is destroyed in this experiment. c) the mass of water is equal to the mass of water vapor produced. d) for the mass of water to be conserved during boiling, the beaker must be closed.

Option C, The mass of water is equal to the mass of water vapor produced.

Explanation:

Josie observed that when she is boiling the water,  it completely turns into water vapor/steam. From this she might have concluded that since it is the liquid water that has evaporated completely, therefore the mass of this water in gaseous phase must be equal to mass of water in liquid phase as only the phase of the substance has changed and not the substance itself. A steam or evaporated water is still water just like liquid water but is gaseous phase.

Hence , option C is correct

your answer is "the 1950's"

condensation. good luck!