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Molecular ChangesMolecular (and Ionic) ChangesNow let's consider what's actually happening at the atomic or molecular level when chemicals dissolve. I will try to illustrate the process using models. There are also some diagrams in example 13 in your workbook to help illustrate what changes are taking place. You have to keep in mind that during the process of dissolving, the process of forming a solution, some bonds are broken, and other bonds are being formed.
The bonds that are being broken are the bonds that are holding the solute together; the bonds that are being formed are the bonds that exist between the solute and the solvent. In general what's happening is that the solute particles, whether they are ions or molecules, are being surrounded by solvent molecules and being pulled away from the others. In order for this to happen, some of the solvent to solvent bonds have to be broken also. In other words, in order for a group of water molecules to surround an ion, that ion has to get in between the water molecules. Which means that not only do you have to break the bonds that exist between that ion and another ion, but you also have to break the bonds that exist between the water molecules that the ions move between.
E-mail instructor: Eden Francis Clackamas Community College |
