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.
Okay, so basically Osmosis is the movement of water molecules from a higher concentration to a lower concentration. Diffusion is generally the movement of a gradient from higher concentration to an area of lower concentration. Osmosis applies to water only, whereas diffusion, you have many types such as Passive transport [ movement of molecules from high- low, NO CELLULAR ENERGY needed! ] then you have faciliated diffusion ( basically uses a channel protein to allow big substances to go through the membrane : NO ENERGY needed]