Definitions to know and understand:
osmosis: diffusion of water
osmolarity: concentration of all particles (solutes) in a solution, in osmoles/liter (osm). Remember that an osmole is defined as the number of moles of particles in one liter solution. This is calculated by adding the concentrations of all particles in a solution, remembering that some solutes dissociate when dissolved in water. For example, 1 mole of NaCl dissociates into 2 moles of particles (Na+ and Cl-). Other examples that you need to know: KCl - into 2 particles; MgCl2 - three particles; CaCl2 - three particles.
isoosmotic: two solutions having equal concentrations of solutes
hypoosmotic: a solution that has a lower concentration of solutes than another solution
hyperosmotic: a solution that has a higher concentration of solutes than another solution
isotonic: two solutions having equal concentrations of impermeable solutes
hypotonic: a solution that has a lower concentration of impermeable solutes than another solution
hypertonic: a solution that has a higher concentration of impermeable solutes than another solution
Sample problems dealing with osmosis