Why a Chest Tube is Placed. A chest tube is placed for a variety of reasons. One reason, as you mentioned, is to help the lung re-inflate when someone has a collapsed lung, also known as a pneumothorax. In that circumstance, a chest tube is inserted along the side of the ribs to allow the lung to reinflate.
A. Osmosis is the passive movement of water from an area high in water concentration, across a semi-permeable membrane, to an area low in water concentration.
Passive transport is the movement of molecules down a concentration gradient (from high to low concentration). Molecules move by random thermal movements. The three different types are simple diffusion, osmosis, and facilitated diffusion. This process does not require energy and the molecule that are transported are moving towards equilibrium.