Video Transcript

Hi, I'm Robin Higgins, and this is what does dissolve mean in Chemistry? So, when we talk about something dissolving, what we mean is that it has separated from itself and it's completely in solution. So, let's look an example we're all familiar with, of salt or sodium chloride. So, at first, if you put salt into water, our little waves here, it act as solid still; it completely falls to the bottom and it's just going to hangs out. Right? And overtime, if we stir it or if we heat it, it dissolves and you can't see it anymore. And so, what's actually happening in terms of Chemistry when that happens, well, salt is formed by ionic bonds and in the water, it separates into positively charge sodium atoms and negatively charge chlorine atoms. So, the reason it dissolves is because it actually interacts with water, so that although the water is here, and of course the waters are H2O and we have little bonds. So, in water, the oxygen atom is actually partial negative and the hydrogens are partial positive. And the positive sodium is attracted to the partial positive, the oxygen and it actually forms little inter-molecular forces in these, the salt completely dissolved. So, the reason that salt dissolves in water is because there are inter-molecular forces in between the positively charged and negatively charged ions of salt in the dipoles of oxygen. And so, the reverse is true with the chlorine. So, chlorine is full negative and it's attracted to the partial positive of hydrogen. And so, the attraction between these guys is strong enough to separate the sodium and the chlorine, chlorine. So, let's look at an example of something that does not dissolve. So, this is a little cube of iron, Fe, it's just hanging out. And if you look at it, you would see that all the iron atoms are bonded to each. So, if you leave that cube of iron in water or you store it or you heat it, you're still going to have that cube of water. It doesn't dissolve, right? And that's because the inter-molecular forces within iron are too strong and they're not interested in bonding with water. So, it doesn't dissolve. I'm Robin Higgins and this has been, "What does dissolve mean in Chemistry?"