Decreases

Gu nther Penzoldt has written:

'Georg Bu chner'

The answer will be the sum of the Flask A and Flask B. The Reason: A gas occupies all the space within a container.

All flasks contain the same number of molecules

From the volume of the flask, and the density of air under the conditions in the room, you can calculate the mass of air. The density of air varies with pressure, temperature, humidity, etc. At sea level and at 15 °C air has a density of approximately 0.001225 g/ml, so under these conditions, a liter flask would contain (1000 ml)(0.001225 g/ml) = 1.225 g of air.