LIVE EXPERIMENTE in Vorlesung: Zink + Schwefel, Gallium + Indium [𝟰𝗞] | JJChemistry

Hello and welcome to a video of a completely different kind. I am currently standing in the preparation room behind the lecture hall, where the first semester chemistry students will have their first chemistry lecture. The special thing about this is that I will be conducting the experiments in this lecture this year. This means that my professor will be holding the lecture herself and I will be preparing all the experiments, I also have a laboratory at the university, and will be conducting all the experiments during the lecture. The special thing about this is that I will be allowed to film. This means that you can also watch all the experiments, like in this video, and the lecture will be quite long. It will be from October to the end of January, which means that there will be a lot of videos together with a lot of nice experiments. For me it is a great honor, something very special, and I wish you a lot of fun with this video series. Oh yes, I have to say one more thing, and that is that I will probably do it in such a way that every video corresponds to a lecture. The lecture is always 90 minutes long and I will cut together all the experiments that we did there, so that every video is like a lecture. I think that makes sense. If there are any changes, I will write them down or say something new in the respective video. Otherwise, you can rely on it. But now, have fun! Lectures are generally very interactive. You are also welcome to answer all of them. Then you have a bit of feedback, what is going on, what you like or don't like. Okay, we'll start with an experiment that most people hopefully know from school. We will now burn a magnesium ribbon and then hold a platinum wire in the flame to find out a few differences. Since we are here in the studio, we will go a bit deeper into the theory, a bit deeper than you might have done in school. This wire is not incredibly bright, but the eyes are shattered by UV radiation that we can't even see. So it's best not to look directly into it. I'm just wearing sunglasses. Our laboratory glasses also have UV protection. That means I can at least look into some of them. Okay, can you see that? Yes, I had the magnesium ribbon no longer in the flame and is burning more and more. I can feel it here too, it's already relatively hot. So what you saw was the characteristic white flame. And what is left is a white solid, magnesium oxide. You might think it's not just magnesium oxide, because interestingly, the reaction keeps on living on its own, even without me adding this energy. I only need it as activation energy. And then a reaction between magnesium and oxygen progresses. I'll take off my glasses, otherwise I look a bit stupid. And what happens next is that the energy is enough to break the nitrogen bond in the air and then react with nitrite. That means we have a mixture of magnesium oxide and magnesium nitrite. And we're going to try to repeat that with a platinum wire. That's a homoeopathic amount. Can you see it like that? Maybe, yes. Wait a minute, I'll put it closer to the burner. Oh yes, can you see it glow? I hope so. So the platinum wire glows pretty fixed. And if I take it out now, it cools down and stops glowing. You can't see that. What can't you see? Which part? Nothing at all. Oh, it wasn't in the cam anymore. Better? That's exactly the feedback I was talking about. Okay, so the platinum wire stops glowing and still glows metallic. That's a good indication that no reaction has occurred. That means platinum remains unchanged. And that's mainly because magnesium is a very non-electric metal and that's why it reacts diligently. And platinum is a very non-electric metal. We have already chosen two extremes. Magnesium as a really non-electric metal and platinum, which can do a lot. And that should illustrate how all the metals can differ. Yes, we will produce a pigment ourselves. This is doubly interesting, because it will certainly be an experiment in the next semester of your internship. Because it's a very nice iron deposit. You only need two chemicals for this. Iron 3 chloride, that's this orange-yellow solution. And once potassium hexacyanoferrate 2. A complicated name. You can shorten it by saying yellow blood cell salt. I hope my camera is not in the way here, by the way. Exactly. I'll overdo it. I'll do it in drops. I think you can see it well. A blue pigment. Oh yes, you can definitely see that. A blue pigment called Berlin blue or Prussian blue. And on your foils, we went one step further as Wikipedia does. We have drawn a three-dimensional structure from a master lecture. And that's the Berlin blue you see here. A nice complex. What you can take away from it is that such inorganic solids, that is a solid that can be filtered afterwards, often have three-dimensional structures. And if you go to a chemist and completely change this structure or an atomic exchange or something like that, then you can vary these properties as you like. For example, in the coloration or something. And that has also been used a lot. And that's why this experiment... I'll just pour everything in here. Then it's gone. Yes, then it looks like ink. We're going to take a look at what iodine looks like when it's sublimated. And when it's resublimated. So in this container here is iodine. Just normal, solid iodine. And the heat plate here is set to 250 degrees. And the glass is heated accordingly. And if I put the solid iodine in here now, you can already see the first glaring vapors. But now we've stepped on the gas. The following happens, and that is, a gas is created directly from solid. And that's iodine. If the glass of the cup would be nice and cool at the top, which it probably isn't, because I've preheated it for a very long time, iodine crystals would form there again. Because it just gets too solid directly from the gas. So resublimated. The silk has different other substances, we just showed that. Certainly very exciting is still dry ice. Maybe we can do that again before Christmas. We'll put in a few intermediate experiments. Exactly, that will also be an experiment. With us it was at least in the C1 internship. I'll say more often which internships the experiments could belong to. Because I didn't give the information at all. I did my bachelor's degree here last year myself. And I know that there should be something like that. And this is one of them. It's going to take a while now, because I've put a lot in there. I'll just let it run. Great, thank you very much. Exactly, what I didn't mention at all. Of course, in addition to the experiments that we have here, which we thought about didactically, which make sense to demonstrate certain concepts, we also planned a small Advent calendar. Because I'm new here, I can't do a big Christmas lecture. That costs a lot of preparation time that I don't have. But JT will make a cool attempt on every lecture day in December, which has nothing to do with the lecture. I think a lot of pyrotechnics. Let's see, we'll evacuate. We'll do our best at the end of the lecture, in case the smoke detectors go off here. We'll go straight on with a little experiment. With two experiments that are very nice. It's slowly moving towards my taste in pyrotechnics. We're going to make a salt that's typically made of a non-metal. For this we have sulfur and a metal zinc. I've already mixed the things up in this can. I'm going to pour a little bit of that in now. I think the trigger is pulling well. The trigger is pulling for sure. Is there a smoke detector in here? We'll see. If not, it's completely remote. Let's see. I'll close the trigger for a moment. That should be good now. A mixture of zinc and sulfur. Stoichiometrically mixed. I'll just throw a miracle candle in there. Best in the same container. I still have enough, actually. We have now produced a salt. Now I can't touch the thing, of course. Stupidly run. What you can see is a yellowish solid. Zinc sulfide. You'll see that more often in the C2 lecture. I promise you that now. The next thing we're going to do is a alloy. I have two metals here. One is gallium. And one is... Wow, really. One is gallium and one is indium. Gallium already has a fairly low melting point of nature. Just 29 degrees Celsius. The melting point of gallium is about 29 degrees Celsius. Contrary to many commentators. This does not mean that it is liquid at room temperature. Below that you understand 20 to 25 degrees. Opposite that is indium. Indium has a melting point of over 150 degrees Celsius. If you rub them together, something pretty nice happens. You have to look closely. Exactly. Totally cool. That's good, right? Okay, I'll rub them together very lightly now. It takes a while. I hope you can see that now. There is definitely a blob. Now I'm going to rub harder. To illustrate this properly. And hold the camera here. A liquid is formed. Can you see that well? Yes, no? Yes, ah yes. Sounds good again. Okay, a liquid is formed. And the whole thing is actually liquid metal. A low-temperature alloy made of indium and gallium. Who would have thought? If I had the two metals here. It has a very exciting property. A melting point of just 11 degrees Celsius. And now there is a freezing point that lies underneath. This means that if you want to make the alloy from solid to liquid, you have to heat it to 11 degrees. And if you want to solidify it again, you have to cool it down to below zero degrees. The whole thing is a typical gallium thing. The effect is called cooling. Okay, we'll do a quick one. If there is no separation of substances. You did it, yes. So here is the iron trichloride solution again. And you want to get the iron ions out of the water. On the one hand, you can do it like this. That would of course work. To produce a dye directly from it. So a color pigment. Or, I'll add ammonia now. Then a red solid is formed. I hope you can see that halfway well. Let's go to the camera. Here you have to see clearly that a solid is formed. Which is now gradually settling on top. Iron hydroxide. And so you could, if I add more, the solution would become clear at the bottom. And so you could filter through. And get an iron-ion-free solution. Instead, there is ammonium chloride in the solution. Which you can simply drip down the drain. It's more about getting rid of the iron trichloride. As it has to be done in practice. Then you will have a lot of fun with filtering and so on. It's really fun. Wonderful. Thank you very much for your attempts today. Great. Then we'll see you tomorrow. Feel free to give feedback.