“How do substances dissolve in other substances?”
Have you ever wondered why some substances can dissolve in other substances? For example, how is it that salt can be completely submerged into water.?To solve this problem, we have to think about it from another perspective, specifically a molecular perspective. To illustrate, let’s start with a an ionic bond-based molecule, such as salt. The salt molecule will be made up of positive sodium ions, and negative chloride ions. And let’s take this salt and put it into an electric dipole molecule based substance such as H20 (water). Because The H20 molecule will have a net charge depending on the location (being more positive closer to the hydrogen, and more negative closer to the oxygen), these parts of the molecules will be attracted to their respective oppositely charged ions of salt. This attraction will be so strong that the water molecules will rip away the intenral bonds of the salt molecule to disperse all of the atoms throughout the substance. Scientists and Engineers have termed the resulting mixture of substances a solution, the substance whose bonds get ripped away the solute, and the substance that absorbs the solute the solvent. The measure of how well a solute can be dissolved in a solvent is called the solubility of the substance
Solutions have numerous peculiar features. Because the solute is so homogeneously dispersed throughout the solvent, a solution can not be filtered. In fact, the solute is so immersed into the solvent that light will not be able to reflect it! However, both substances will still have different boiling points, so the solution can be separated through evaporation, as one of the substances will boil away before the other one.
Because of the laws of physics, polar compounds will be able to dissolve ionic and polar compounds, but only non-polar compounds will be able to dissolve other non-polar compounds. That’s why you can put water into plastic and not have to worry about chemichal reactions (as plastic is a non-polar substance). Solid solutes dissolve better in liquid solvents when they have a higher temperature (due to closer entropy levels to the liquids) and Gaseous solvents work better when they have lower temperature (for the same reason). Gaseous solvents also have better solubility with increased pressures