PV=nRT is the ideal-gas formula, which explains the proportionality relationship between pressure, volume and temperature. In the equation, P represents pressure measured in atmospheres, V is volume measured in liters, T is temperature measured in degrees Kelvin, R is the gas constant equal to 0.08206 Liter-atm/ K-mole, and n represents the number of moles of a substance being measured. A mole is defined as the amount of any element needed to equal the number of atoms in exactly 12 grams of carbon-12
Wt% = mass of the solute in solution / mass of the solution. This allows you to express concentration of a solute dissolved in a solvent. A solute is any substance that is dissolved in a solvent. With this equation, for instance, you can calculate the amount of dye required to make a solution of the proper strength for the color desired when dyeing fabric or yarn.
Osmosis is the movement of solvent particles, but not solute particles, through a semipermeable membrane from a more dilute solution to a more concentrated one. A solvent is any chemical used to dissolve a solid and a solute is any solid that is dissolved by a solvent. The osmotic pressure is the amount of pressure required to prevent migration of the solvent to the more dilute solution through the membrane. This concept is the basis for administering an intravenous transfusion to deliver necessary fluids to a body's cells. The formula used to calculate this is Pi = MRT where M is molarity, the number of moles of a solute in a liter of solution; R is the ideal gas constant; and T is the temperature. Pi represents the osmotic pressure value, not the usual 3.14 "pi" used in geometry.