How does the ballon get in to the flask?

A volumetric flask is a container that is used to measure the volume of a liquid with extremely high accuracy. It is the best way to measure a specific quantity of a liquid. It cannot be used to...

They are containers for liquids, or more rarely, for gasses.

It's named after the city of Florence in Italy.

They are the same thing, a thermos flask is just a different name for it. A vacuum flask is the original name.

Yes, sort of a cylindrical pyramid shape, if you can imagine that. In Pyrex they are supposed to be better adapted to boiling and condensing liquids at high temperatures. Glad you are using big...