ChemistryWiki | RecentChanges | Preferences
As you know, the solute dissolves/miscible in the solvent by the coloumbic force (CF) of the solvent being stronger than the CF of the solute particles to themselves. The basic unit of the solute along with the solvent particles create a new entity, hydrated ion or molecule that take up the empty space between the solvent particles. Therefore, only a specific amount of solute can dissolve/miscible in a given amount of solvent.
People sometimes want to know how fast the solute dissolves into the solvent (rate of dissolving). There are 4 factors that affect the rate of dissolving, stirring, temperature, surface area, and concentration.These factors do not change if a solute dissolves or not in a solvent. That is determined by the IMF or the type of solute and solvent you have. Remember, Like dissolves Like.
Surface area and stirring
Both of these factors are basically the same. To dissolve/miscible, you need solvent particles near solute particles. The solute particles in the middle of a non stirred solute and in the middle of an unpulverized solute can not interact with a solvent particles. Therefore, they can not dissolve. So separating the solute particles will increase the number of solute and solvent particles that can interact thereby increase the number of solute that can dissolve in a given time (i.e. increase rate of dissolving).
Temperature
Since all the particles are moving faster/have higher kinetic energy, the solvent particles remove the solute particles more in a given time thereby increasing rate of dissolving.
Concentration of the solution
As you approach the solubility of the solution at a given temperature, there are less and less empty space (or another way of saying it is there are less and less solvent particles that are not part of a hydrated ion/molecules) so solute particles "take longer" to find empty space (or water particles to interact with). So the higher the concentration of the solution (thereby closer to concentration of the saturated solution), the rate of the dissolving decreases.