Types of Solutes and Dissolution vs. Dissociation

Need help preparing for the General Chemistry section of the MCAT? MedSchoolCoach expert, Ken Tao, will teach you about the types of solutes and dissolution versus dissociation of solutions. Watch this video to get all the MCAT study tips you need to do well on this section of the exam!
A solute is the less abundant component of a solution, dissolved in a solvent. We are able to classify the types of solutes as strong or weak electrolytes, and polar or nonpolar nonelectrolytes. Classifying solutes in this way will let us create a mental map of which solutes are better able to dissolve in a polar solution.
Electrolytes versus Nonelectrolytes
Recall that electricity is conducted by ionic solutions, because the ions of such solutions are free to move about. Electrolytes are thus solutes that can dissociate into ions. An example of such a solute is table salt, composed of the anion chloride and cation sodium. Conversely, non-electrolytes are solutes that cannot dissociate into ions in solution. For instance, glucose is an organic compound which is not composed of dissociable ions.
Polar versus Nonpolar Nonelectrolytes
Nonelectrolytes can be further classified as polar or nonpolar. Returning to our example of the nonelectrolyte glucose, the asymmetry of its structure leads us to understand that it’s polar. As a polar solute, glucose would be able to favorably interact with water. Conversely, an example of a non-polar nonelectrolyte is hexane. Hexane is a hydrocarbon, which is a non-polar compound. Hexane added to a solution of polar water would not be able to dissolve.
Strong and Weak Electrolytes
Electrolytes can also be classified as strong or weak electrolytes. The difference between a weak electrolyte and a strong electrolyte is the degree of dissociation in a solvent. Stronger electrolytes dissociate completely into ions in solution, whereas weak electrolytes only partially dissociate. Strong acids and bases are all examples of strong electrolytes. Conversely, weak acids and bases are weak electrolytes, only partially dissociating in solution.
Dissolution versus Dissociation
Dissolution is the process by which solute molecules in solution separate and solvent molecules separate. Dissolution is an endothermic process because the intermolecular forces holding together molecules of solvent need to be overcome with additional energy, and in addition, the intermolecular forces holding together solvent molecules must be overcome with additional energy. Dissociation is the process by which ion pairs separate into their constituent cations and anions. Dissociation is also an endothermic process, because it requires breaking the ionic bond holding the cation and the anion together in an electrolytic pair.
Following both dissolution and dissociation is an energetically favorable process called solvation. After solute molecules undergo dissolution or electrolytes dissociate, individual solute molecules are able to form interactions with water. Solvation involves the formation of intermolecular forces, which releases energy and is thus an exothermic process. This release of energy is what can make dissolution and dissociation an overall energetically favorable process. Note that when water is a solvent, solvation is termed “hydration”.
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[@lucasstadler3059]

This video just made me understand this so much better. You explained this very well. Thank you very much.

[@rudrashishmajumdar4251]

extremely important Topic
thank you

[@dominicestebanrice7460]

Superb!

[@arishakhan3939]

amazing explanation!!!!!!

[@gaditproductions]

Is hydration same as dehydration synthesis?

[@sharduljadhav250]

Thanks a lot!!

[@hamzahal-nuaimy-8357]

I am confused about the last part isn’t salt and sodium chloride are the same thing??

[@pookie247]

do you know candice?

[@coco.chrisps]

a salt refers to an ionic compound! It just so happens salt in English also means NaCl (referring to table salt)