Today, we made solutions of sugar-water and saltwater. Now, you might be wondering, “what’s a solution?” So let’s define a solution as a heterogeneous mixture of two or more pure substances. The first compound is called a solute, and it is the one that is dissolved when dropped into the other substance. The second compound is called the solvent, it is present in the largest quantity, and it is the one that actually does the dissolving part and breaks down the solute into either individual molecules or ions. Additionally, to be dissolved basically means “to be surrounded by water or some other liquid.”
Moving on, we couldn’t differentiate between the salt mix and the sugar mix with 100% certainty, so we decided to do some thinking. We reasoned that salt, NaCl, was an ionic compound while the sugar sucrose, C12H22O11, was not. We hypothesized that the salt itself might break down into its individual Na+ and Cl– ions, and therefore it would conduct electricity if a current was passed through it. This also meant that the sugar wouldn’t conduct electricity, and also pure water wouldn’t either, since it isn’t really made out of ions, either. So, we used a little light bulb with metal prongs on it, stuck the prongs into the solutions, and found that saltwater conducted and made the bulb glow, and neither sugar water nor pure/deionized water didn’t conduct.
We also learned that a solution like saltwater was called an electrolyte, whose definition is “a solution composed of dissolved ions, which will conduce electricity.” By extension, a non-electrolyte is just “a solution that isn’t composed of ions, and so which doesn’t conduce electricity.”
Furthermore, here are some particle diagrams of our two solutions:
One of water’s properties is what is known as polarity: it has both positive and negative charges, depending on which side it faces; the side with the oxygen on it has a partial negative charge, and the side with the two hydrogens on it has a partial positive charge. This means that the oxygen atoms will face in towards the positive Na cations, while the hydrogen atoms will face in towards the negative Cl anions. However, the sugar molecules weren’t made out of ions, so they simply broke down into individual sucrose molecules instead of into ions, and so each molecule was still electrically neutral and didn’t attract any particular side of the water molecules.