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Current time:0:00Total duration:5:26

Video transcript

during the dehydration experiment ethene gas and unreacted ethanol passed through the tube into the water the ethene was quantitatively collected as a gas but the unreacted ethanol was not explained this observation in terms of the intermolecular forces between water and each of the two gases and just to be clear what they're talking about we can go to the original setup that they gave us at the beginning of this problem and what they're saying is is through this when they warm up they'll react this the catalyst and the ethanol in here some of that ethanol gets converted into Athene but not all of it does in fact part of this experiment we saw that we don't have a perfect we have a 60 point something percent yield and so you have a combination of ethanol and ethene gas going through this tube it cools down then it goes through this water and they're saying it looks like we're only seeing or we're primarily seeing the ethene gas here how come we're not seeing the ethanol gas and the reason and I'll just paraphrase it right now and then I'll write it down is that the ethanol the ethanol gas is much more dissolvable in the water because ethanol is a polar molecule water is a polar solvent so it's going to it's going to it's going to dissolve much better in water than the ethene which isn't a polar molecule so let me let me write this down so the ethene will kind of bubble through while the ethanol can actually dissolve so let's write this down so oops I'm having trouble all right there you go so explain this observation in terms of intermolecular forces between water and each of the two gases so we could write ethanol ethanol is polar polar so it dissolves in water much better than then Athene which is non non polar and so we could say something like so ethanol ethanol and water and water will have hydrogen bonds will have hydrogen bonds hydrogen bonds you can even diagram it out if you like the ethanol is right over here so you have your oxygen and then you have your hydrogen and then you have your c2h5 this side over here this is going to be partially negative this is going to be partially positive this is going to oxygen is more electronegative than carbon the difference is less than between oxygen and hydrogen but this is also going to be partially positive maybe not as partially positive it's on this side right over here and so when you have water molecules so this is a water molecule right over here where this was partially positive charges partially negative charges you're going to have the hydrogen bonds hydrogen hydrogen bonds and so the ethanol is going to dissolve much better you could the ethene isn't polar and will only have induced dipole forces acting on it so let me write this ethene ethene is not polar is not polar and so are to take so we'll only have induced dipole interactions induced dipole and maybe well I could say dipole because well the water is the water is polar and even though ethene is metrical molecule it has that double bond it has no net polarity there are parts of the ethene molecule that are going to be a little bit more negative than others in particular when you look at when you look at the carbons over here they're a little bit more electronegative than the hydrogen's and so ethene is not polar so we'll only have induced dipole or I guess we could also say just dipole interactions interactions interactions with polar water polar water and so this is why so this is why ethene won't dissolve as well ethene won't dissolve as well and bubbles through and bubbles through ethanol dissolves ethene bubbles through cuz it's not it doesn't have a strong interactions with the water
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