CZ2 SALTS
This eighth-grade science lesson is about chemical compounds. It is the 10th lesson in a sequence of 12 lessons on salts. The lesson is 45 minutes in duration. There are 30 students in the class.
| Time | Caption |
|---|---|
| 00:00:03 | I'm going to- |
| 00:00:05 | Why don't we all stand up. Please be quiet. You may sit down. |
| 00:00:17 | I would like to find out, who's missing? |
| 00:00:21 | So, that will be- (Novakova) and (Kolarova). |
| 00:00:27 | (Novakova) and (Kolarova). |
| 00:00:58 | Today, we're going to start off, by giving someone an oral quiz. It's going to be (Straka). Take the chalk and stand up behind the blackboard. |
| 00:01:09 | (Stojkova) is next. (Stojkova). Please take the chalk and stand behind the second part of the blackboard. |
| 00:01:21 | (Terner) and (Vojtikova). You two will write up at the front of the blackboard. |
| 00:01:25 | The entire class will open their notebooks from the back. Everyone else- as always, we'll write formulas. |
| 00:01:38 | Okay, let's begin. Is everyone ready? I would also like to divide the class into two groups of A and B. |
| 00:01:48 | Please make an effort not to look at your neighbor's work. |
| 00:01:56 | Okay, let's begin. Calcium chloride, calcium chloride. |
| 00:02:09 | Potassium sulphite, potassium sulphite, potassium sulphite. |
| 00:02:26 | The next formula is, ammonium bicarbonate, ammonium bicarbonate, ammonium bicarbonate. |
| 00:02:54 | The next formula is, copper sulfate. |
| 00:03:23 | The last formula is very difficult. It's called, sodium tetraborate, sodium tetraborate. |
| 00:04:00 | Okay. Please step back from the blackboard. Exchange your work with your neighbors. |
| 00:04:14 | Those of you who are sitting alone, can offer their work to anybody in the class. Okay, we're finished. |
| 00:04:25 | Now, we're going to correct and check our work. Let's start with the students, who are up here by the board. |
| 00:04:37 | The first one is calcium chloride. Which formula is correct and which one isn't? |
| 00:04:46 | CaCl2. |
| 00:04:47 | CaCl2. What about here- why did you write CaCl? Why did you write CaCl? Can you explain it to us? |
| 00:05:01 | Because I thought that the oxidation value of the chlorine is negative one. |
| 00:05:06 | Very good. So, you knew that the oxidation value of calcium is two and the oxidation value chlorine is negative one. Very good. |
| 00:05:18 | How about the second formula. Okay? |
| 00:05:26 | The second formula is? Please read the formula that you wrote down. Read it. |
| 00:05:35 | Sulphite- |
| 00:05:37 | Just read the formula. //K2 |
| 00:05:38 | //K2SO3. |
| 00:05:40 | Is it correct, everyone? |
| 00:05:42 | Yes. |
| 00:05:43 | Yes. Okay, both formulas are correct. This was supposed to be ammonium bicarbonate. Which one of those formulas is correct? |
| 00:05:54 | Is it correct? Did one of them, write it correctly? |
| 00:05:56 | This one, here. Dusan's. |
| 00:05:58 | Yes. So- |
| 00:05:59 | I have it in the inside. |
| 00:06:01 | This formula is correct, this formula is incorrect. Completely wrong. Okay? The next formula is supposed to be anhydrous copper sulfate. Is it correct? |
| 00:06:14 | Yes. |
| 00:06:15 | Yes, it is. This one is not even here. And the last one is sodium tetraborate. Is this formula correct? |
| 00:06:26 | Yes, yes. |
| 00:06:28 | Those of you that agree with him, please raise your hand. Okay, good. |
| 00:06:33 | Sodium tetraborate is okay because the oxidation value of boron is- |
| 00:06:38 | Three. |
| 00:06:39 | Three. Very good and let's sit down. Now, we'll assign grades. Okay. |
| 00:06:46 | All these formulas here were correct. We'll give an A grade. This one has two incorrect and one is missing so we'll give it a C grade. |
| 00:07:00 | Yes, the C grade. The last formula is- okay, grade C. |
| 00:07:05 | On this side of the board- we'll just confirm the formulas. Correct, correct, correct. This one is also correct, yes? This one is also correct. |
| 00:07:17 | This student gets an A. And here? This student gets an A as well. Everything is correct. So that one gets the letter grade A and so does this one. |
| 00:07:29 | Please step away from the board. Now, everybody in class, please open your books. Group A, will look up page 114. There is a table, number nine. |
| 00:07:56 | Please fill out the table with your pencil. Okay? Group B of the class, turns to page 118. |
| 00:08:05 | It's the assignment number five and there is a table. Fill it out with your pencil as well. |
| 00:08:12 | And those of you up here, we will continue. I will ask you some questions and you will answer them. Okay? Fertilizers. |
| 00:08:23 | Fertilizers are actually- |
| 00:08:25 | Take your hands out of your pockets. |
| 00:08:26 | They are substances, which give nutrients to living plants and soil, during the vegetation growth. |
| 00:08:36 | During the vegetation growth. Can you name some fertilizers? |
| 00:08:41 | Mineral fertilizers. |
| 00:08:42 | Mineral fertilizers. Can you think of other fertilizers? |
| 00:08:45 | Organic fertilizers. |
| 00:08:46 | Organic fertilizers. Can you name some organic fertilizers? |
| 00:08:48 | Those can be found on ranches and farms. |
| 00:08:50 | And they are? |
| 00:08:52 | Manure, sewage. |
| 00:08:55 | Sewage. |
| 00:08:57 | And wastewater. |
| 00:09:00 | The wastewater. Are there any other organic fertilizers, which you can name? |
| 00:09:04 | No. You've mentioned all of them. What is a mineral fertilizer? Do you know of any mineral fertilizers? |
| 00:09:10 | Potassium chloride, for example? |
| 00:09:14 | Yes, it may be potassium chloride. But what about some different ones, can you name any? |
| 00:09:21 | Crushed limestone. |
| 00:09:23 | Crushed limestone, excellent. What fertilizers, other than organic, do you know of? |
| 00:09:28 | Industrial fertilizers. |
| 00:09:29 | Industrial fertilizer. Can you name a few? |
| 00:09:31 | Those are- |
| 00:09:32 | The rest of you, must do your work quietly. |
| 00:09:36 | Single element fertilizers and the multiple elements fertilizers. |
| 00:09:38 | Single element fertilizers and the multiple elements fertilizers. Name some single element fertilizers? |
| 00:09:42 | Phosphate, nitrogen, and potassium. |
| 00:09:48 | Potassium fertilizers, yes. Nitrogen, phosphate- please do your work quietly. Okay, next one. |
| 00:09:57 | The ceramic industry, creates ceramics. What kind of ceramics do we know? |
| 00:10:04 | The standard kind, for example. |
| 00:10:05 | The standard. What is considered the standard ceramics? |
| 00:10:09 | The (inaudible). |
| 00:10:17 | Okay. What is considered the standard ceramics? Please name a few, for us? |
| 00:10:22 | The sink. |
| 00:10:24 | The sink, for instance. |
| 00:10:25 | Tiles. |
| 00:10:26 | Tiles, tiles. |
| 00:10:28 | Toilets. |
| 00:10:29 | Toilet sinks, correct. Anything else? What other ceramics do you know? |
| 00:10:34 | Rough ceramics. |
| 00:10:35 | Rough ceramics. Name some rough- |
| 00:10:37 | Rough ceramics. Those are mostly ceramics, which are used in construction. Roof tiles, for example. |
| 00:10:44 | Roof tiles. Can you think of other items? How would we categorize pottery, for instance? |
| 00:10:53 | Those fall under rough ceramics. |
| 00:10:56 | It falls under rough ceramics as well. Are there other ceramics? |
| 00:11:00 | It could be plates or (inaudible) and vases. |
| 00:11:06 | Okay. What are these items made of? |
| 00:11:12 | Clay and (glass). |
| 00:11:15 | We've said that the fine ceramic is made out of what? Of what? |
| 00:11:22 | Kaolin. |
| 00:11:23 | It's made out of kaolin. Yes. It's made out of kaolin. What is the kaolin? What is the kaolin? Is it being mined in the //Czech Republic? |
| 00:11:31 | //Yes. |
| 00:11:32 | Yes, what is produced- it's clay, which is being mined in this country. At what part of the country is kaolin being mined? |
| 00:11:42 | The Czech Heights. |
| 00:11:45 | Well, around major cities. Can you name a city? |
| 00:11:49 | Karlovy Vary. |
| 00:11:50 | Karlovy Vary, for instance. Very good. Now everyone, grab a piece of chalk because you will write your grade. |
| 00:12:00 | This student gets a B grade, you get an A, you get a B and you get an A. Those are your grades. |
| 00:12:09 | And for the final evaluation, please write some chemical reactions. How about the reaction of hydrochloric acid with sodium hydroxide. |
| 00:12:20 | Hydrochloric acid plus sodium hydroxide. Sodium hydroxide. Everyone is doing it on their own. Sodium hydroxide. Okay. |
| 00:12:34 | Do you know how to complete the chemical reaction? |
| 00:12:42 | Okay? Underneath that, please write, what type of reaction is it? What kind of reaction is it? |
| 00:12:56 | Okay. Very good, very good. |
| 00:13:09 | And it is a neutralization. This one is correct. Very good. You may go back to your seats and I'll give you your grades. |
| 00:13:16 | So, I think (Straka) will get an A because he did a remarkable job. Next student is (Terner), he will also get an A. |
| 00:13:34 | (Stojkova). |
| 00:13:35 | (Stojkova) gets a lower A grade and... |
| 00:13:41 | (Vojtikova). |
| 00:13:42 | (Vojtikova) also gets an A minus. Over all, it was pretty good. Please sit down. |
| 00:13:53 | Okay. Now I would like to ask the entire class- on page one- 114. The table. Which of you did not fill it out? |
| 00:14:08 | Obviously, those of you, that were up here, did not do the table. Did anyone not complete it? Did anyone have difficulties with anything? |
| 00:14:15 | No? Okay. You did? Okay, what's the problem? |
| 00:14:19 | Bluestone. |
| 00:14:20 | The bluestone. What is it that you don't know? The chemical formula? |
| 00:14:24 | Yes. No, the chemical name. |
| 00:14:26 | The chemical name. Which of you knows the chemical name of the bluestone? |
| 00:14:31 | Copper sulfate pentahydrate. |
| 00:14:32 | Copper sulfate pentahydrate. Come up here and write up the formula. Copper sulfate pentahydrate. |
| 00:14:40 | May I take this book with me? |
| 00:14:41 | No, just come up here to the board really fast, so you don't waste time. Copper sulfate pentahydrate. |
| 00:14:52 | Okay. So the only thing that you had trouble with was the name, bluestone. |
| 00:14:57 | Yes. |
| 00:14:58 | Okay. Please sit down. Very good. The second table graph, letter B. It's on page 118. Which of you had trouble with this one? |
| 00:15:10 | Okay, which one? |
| 00:15:11 | The common name for calcium sulfate hemihydrate. |
| 00:15:14 | Okay. Calcium sulfate hemihydrate. Who knows the name of- hemi means, half of something. |
| 00:15:23 | Plaster. |
| 00:15:24 | Yes, it is plaster. It's a baked plaster. Okay, we all write the baked plaster in our tables. Any other problems? |
| 00:15:33 | Okay. We- |
| 00:15:35 | The name of potassium permanganate. |
| 00:15:36 | The name of potassium permanganate. Wait a minute, we can already derive that one, we already have the formula of KMNO4. Which one is it? |
| 00:15:45 | Manganese potassium. |
| 00:15:46 | Excellent. It's the manganese potassium. |
| 00:15:49 | Okay, I'm not going to go over your correct answers because I want you to use the answers in the following table, which we'll be working on. |
| 00:16:01 | In this class, we have to discuss the use of the salts and the chemical reactions with salts. Okay. Please erase the board, erase the board, quickly. |
| 00:16:24 | While he's erasing the blackboard, we can distribute the following tables. Okay? Here, distribute these all over the classroom. |
| 00:16:37 | You, as well. Let's speed it up. Why don't you distribute these as well? |
| 00:17:02 | No, no. That's enough. |
| 00:17:19 | Okay. In our previous lesson, we've introduced the chemical nomenclature of salts, how to write the formulas, and what some of the salts look like. |
| 00:17:29 | And today, we'll finalize all this information and we'll complete the table, which is in front of you. |
| 00:17:38 | I will turn off the lights, so we can take a look- everyone can orient themselves, so I know where- |
| 00:17:48 | We'll view the table on the overhead projector. Everyone will orient themselves. Okay. Everyone at the same time. |
| 00:18:02 | Here we have the first salt. What is the first salt called? Who can tell us? |
| 00:18:08 | Potassium chloride. |
| 00:18:09 | Potassium chloride. It's here. Can we write the formula? |
| 00:18:14 | KCl. |
| 00:18:15 | KCl. Please fill in KCl in the- into the table. Potassium chloride. Do you know the common name or do you know the name of the mineral in which- |
| 00:18:30 | Rock salt. |
| 00:18:31 | No, it's not rock salt. Potassium chloride or sylvine. Okay, so why don't you write sylvine, sylvine. It's a mineral, which is potassium chloride. |
| 00:18:54 | The next thing is, coming up with an example of the usage. Can you recall a situation, where the potassium chloride can- |
| 00:19:02 | Industrial fertilizer. |
| 00:19:03 | Yes, it is the industrial fertilizer. Why don't you write, industrial fertilizer. Okay. |
| 00:19:13 | KOH can be also produced from it. What is the KOH? |
| 00:19:17 | Potassium hydroxide. |
| 00:19:18 | Potassium hydroxide. Very good. Please write, KOH. Okay. The next- the next one is? |
| 00:19:29 | (inaudible). |
| 00:19:30 | We have NaCl. What is it? |
| 00:19:33 | Sodium chloride. |
| 00:19:34 | Sodium chloride. Yes. The name of this formula is sodium chloride. |
| 00:19:41 | Can anyone tell me the common name or mineral? |
| 00:19:48 | Rock salt. |
| 00:19:49 | Rock salt. Have you ever seen it? |
| 00:19:52 | Yes. |
| 00:19:53 | Where have you seen it? |
| 00:19:55 | In the household. |
| 00:19:56 | In the household, which is in the kitchen. I brought you a large piece of salt. I'm sure, you've never seen this kind before. |
| 00:20:03 | Here, take a look. This large piece is only one crystal. |
| 00:20:06 | We've seen this before. |
| 00:20:07 | You've seen this in your geology class, for instance. Okay. So this is a solid salt crystal. Yes. Beautiful crystal. |
| 00:20:19 | Very good. Okay, what is the salt being used for? |
| 00:20:24 | In the household. |
| 00:20:25 | At home as seasoning. What else is it used for? |
| 00:20:32 | For cleaning of the surface of the metals. |
| 00:20:34 | I don't think so. I would say- |
| 00:20:39 | For animals? |
| 00:20:40 | Food additive for animals. But what can be produced from it? Some kind of hydroxide. What kind? |
| 00:20:49 | Sodium. |
| 00:20:50 | The sodium, yes. Why don't you write, the production of KOH- NaOH. Good. The next salt on the list is? Let's take a look. |
| 00:21:03 | Ammonium chloride. Please take good notes because this table will be used as the review. Everything you write in, you must memorize. Okay. |
| 00:21:16 | Ammonium chloride. What is the formula for that? |
| 00:21:19 | NH4Cl. |
| 00:21:20 | Excuse me? |
| 00:21:22 | NH4Cl. |
| 00:21:23 | NH4Cl. Yes. NH4Cl. Do you know the common name? |
| 00:21:30 | Sal ammoniac. |
| 00:21:31 | Sal ammoniac. Very good. Sal ammoniac. Can someone tell me- has anybody seen the sal ammoniac? The look of it? |
| 00:21:41 | (Maybe). |
| 00:21:42 | No, you haven't seen it. I brought these tools here, to show you how easily it can be produced. What is the sal ammoniac produced from, what do you think? Take a look here. |
| 00:21:55 | (inaudible). |
| 00:21:57 | Yes. So, we're going to use hydrochloric acid. |
| 00:22:00 | Hydrochloric. |
| 00:22:01 | Hydrochloric acid. Let's take a look here. The hydrochloric acid. I'm pouring a small amount, into the graduated cylinder. It only takes a very small amount. |
| 00:22:16 | And what is the second matter, we'll be using? |
| 00:22:19 | Ammonia. |
| 00:22:20 | Ammonia, very good. It's also called ammonium hydroxide. Yes. Ammonium hydroxide. Take a look what is being created. It's going to be sal ammoniac. |
| 00:22:34 | Take a look. Do you see it? Here it is. |
| 00:22:41 | It's very beautiful. So these white vapors are sal ammoniac. Okay? |
| 00:22:48 | Is it poisonous? |
| 00:22:49 | Well it's not poisonous. But- are you familiar with term sal ammoniac, what is it used for? I have already heard it here- |
| 00:23:00 | For cleaning. |
| 00:23:01 | Yes, very good. For cleaning. I will cover the beaker, so it doesn't stink up the room. Okay. Sal ammoniac. |
| 00:23:15 | What is the next salt, is on the list? |
| 00:23:20 | Sodium nitrate. Sodium nitrate is poisonous. What is the formula? Everyone will write the formula. Please write it down. You wrote it down already? |
| 00:23:32 | NaNO3. |
| 00:23:34 | NaNO3 is sodium nitrate. Okay. |
| 00:23:38 | Is it poisonous? I got it mixed up with silver sodium. I was ahead of myself. The sodium nitrate is not poisonous. |
| 00:23:47 | But it's- what is the common name for it? What is it? |
| 00:23:53 | Saltpeter. |
| 00:23:54 | Saltpeter. Very good. It's saltpeter. Why don't you write saltpeter? |
| 00:23:59 | Okay. Nitrate- where is saltpeter being used? |
| 00:24:04 | Fertilizer. |
| 00:24:05 | The saltpeter fertilizer. Very good. Why don't you write, saltpeter as the fertilizer. Okay? |
| 00:24:13 | In the table, we'll skip potassium nitrate because it's very similar to the previous one. Okay? Just tell me the formula. |
| 00:24:22 | KNO3. |
| 00:24:24 | KNO3. Fill in your table for potassium nitrate. The silver nitrate. The formula for that is? Please raise your hands. |
| 00:24:38 | AgNO3. |
| 00:24:39 | AgNO3. Is everyone keeping up with the writing? Yes. The silver nitrate. Where can we find that? |
| 00:24:49 | Caustic. |
| 00:24:50 | Caustic. What does caustic mean? |
| 00:24:52 | Warts. |
| 00:24:53 | For warts. Correct. So, where is it being used? |
| 00:24:57 | The pharmacy. |
| 00:24:58 | In medicine, for example. Yes, in medicine. |
| 00:25:02 | Why don't you, Jonasi, read the next formula, which is in the table. It's this one. It's this formula. |
| 00:25:13 | (inaudible)? |
| 00:25:16 | Yes. |
| 00:25:17 | CuSO4, 5H2O. |
| 00:25:19 | Can you read the written format? |
| 00:25:21 | Copper sulfate pentahydrate. |
| 00:25:25 | Copper sulfate pentahydrate. Correct. Everyone will write, copper sulfate pentahydrate. What is the name of it? |
| 00:25:37 | Blue vitriol. |
| 00:25:38 | Blue vitriol. Did you all see blue vitriol? I took the opportunity to bring in- show you from the laboratory, these crystals or blue vitriol. |
| 00:25:54 | Why don't you take a look at this beautiful- |
| 00:25:56 | We've done that as well. |
| 00:25:57 | You've experimented with this matter already? During- |
| 00:25:59 | During our chemical experimenting. |
| 00:26:00 | During your chemical experimenting. Okay. That's how blue vitriol looks like, which you observed this summer in your study. |
| 00:26:11 | Where is blue vitriol being used? |
| 00:26:14 | For controlling the growth, for example. |
| 00:26:15 | Excuse me? |
| 00:26:16 | For controlling the growth, for example. |
| 00:26:17 | Very good. Why don't you write... you can even write, disinfectant products against mold or the controlling of growth against mold. |
| 00:26:30 | And as metal coating, for instance. Okay? We have the word green below that. Yes? What word is missing there? What is- |
| 00:26:41 | Green vitriol. |
| 00:26:42 | Green vitriol. What actually, is green vitriol? There is a formula of FeSO4 times 7H2O. How would you read that? |
| 00:26:56 | Iron sulfate heptahydrate. |
| 00:26:58 | Iron sulfate heptahydrate. Very good. Who has seen the green vitriol? No one. It's a good thing that I brought it with me. |
| 00:27:09 | Unfortunately, I left it upstairs, so I don't have it here. It's green and very similar to the crystal matter. It's used against the moss. Okay? |
| 00:27:22 | Why don't you write, the moss. Okay, the next one is CaSO4. CaSO4 times 2H2O. How do we read the formula, for that one? |
| 00:27:34 | Not everyone has been raising their hands. How about back there. Shirek? |
| 00:27:38 | Calcium sulfate. |
| 00:27:39 | Excuse me? |
| 00:27:40 | Calcium sulfate. |
| 00:27:41 | But the 2? H2O? |
| 00:27:44 | Calcium sulfate dihydrate. |
| 00:27:45 | Calcium sulfate dihydrate. Yes. What is the common name? Dehydrated- |
| 00:27:53 | Gypsum. |
| 00:27:54 | It is gypsum. Correct. It is gypsum. What is gypsum used for? |
| 00:28:03 | The production of plaster. |
| 00:28:04 | The production of plaster. Let's all write, the production of plaster. The production of plaster. |
| 00:28:12 | Very good. The next one is, sodium carbonate. What is the formula for sodium carbonate? |
| 00:28:21 | Na2CO3. |
| 00:28:22 | Na2CO3. Na2CO3. Which of you have seen the word, soda. |
| 00:28:30 | (inaudible). |
| 00:28:31 | Soda. That's the common name. So, the common name is soda. But be careful. Soda must have what? |
| 00:28:43 | (inaudible). |
| 00:28:44 | Excuse me? It must include water. Now I want to show all of you the soda. I brought it with me. |
| 00:28:55 | So it's- it's not- soda is a crystal matter. Here, take a look at the soda. Please take a look at the soda. |
| 00:29:06 | What does it look like? How would you characterize it? |
| 00:29:10 | White, powder. |
| 00:29:12 | White, without color. White, crystallized matter. Okay? |
| 00:29:17 | Everyone can see the soda. What is soda used for? |
| 00:29:22 | The production of soap. |
| 00:29:24 | The production of soap. Very good. So, why don't you all write the production of soap? //Anywhere else? |
| 00:29:28 | //Glass. |
| 00:29:29 | The glass. Excellent. Is it also being used somewhere in the household? |
| 00:29:33 | Softening water. |
| 00:29:34 | The softening of water. Okay. So, the softening of hard water. Okay? |
| 00:29:48 | The next one is? The formula is, NaHCO3. What is that? |
| 00:29:55 | Sodium hydrogen carbonate. |
| 00:29:56 | Sodium hydrogen carbonate. Sodium hydrogen carbonate. Does anybody know- did someone come across it? |
| 00:30:06 | Sodium bicarbonate. |
| 00:30:07 | Sodium bicarbonate. Very good. Sodium bicarbonate. Good observation. Excuse me? |
| 00:30:13 | The common name. |
| 00:30:14 | Well, we can use it as the common name. Sodium bicarbonate. Has anyone used sodium bicarbonate? What is it good for? |
| 00:30:24 | For the stomach. |
| 00:30:25 | To prevent stomach acid. Good. The prevention of stomach acid. |
| 00:30:32 | We're going to skip the carbonated potassium because it's being used for- we'll leave it alone. Calcium carbonate. Calcium carbonate? |
| 00:30:44 | CaCO3. |
| 00:30:45 | CaCO3.Everyone should write, CaCO3. What is the name of the carbonate- as a mineral? How about you. |
| 00:30:56 | Calcium. |
| 00:30:58 | Me? |
| 00:30:59 | Yes. |
| 00:30:59 | Calcium. |
| 00:31:00 | Or what's the other word? |
| 00:31:01 | Limestone. |
| 00:31:02 | So that is a mineral. |
| 00:31:03 | Mountain limestone. |
| 00:31:04 | Mountain limestone. Yes, the limestone. Can someone tell me- we've already seen the solidification of cement, slaked lime? |
| 00:31:18 | So, what is it used for? What is the limestone used for? |
| 00:31:22 | Burned lime. |
| 00:31:24 | Burned lime. So, why don't you write, the burning of lime. |
| 00:31:29 | Can someone tell me, what the burned lime is? What is it? |
| 00:31:34 | CaO. |
| 00:31:35 | CaO. You've had geology, earlier today. Correct? |
| 00:31:38 | Yes. |
| 00:31:39 | In your previous class. I wanted to ask you, didn't you also learn- |
| 00:31:44 | Limestone. |
| 00:31:45 | Limestone. And what is created from the limestone? |
| 00:31:48 | (inaudible). |
| 00:31:49 | The limestone or the karst-like process. Yes? Do you know the main reason for the karst-like process? |
| 00:31:57 | Sun and... limestone precipitates out. |
| 00:31:59 | Well, limestone precipitates, it creates calcite. And what grows from that? //Stalagmite. |
| 00:32:06 | //Stalagmite |
| 00:32:07 | Yes. The stalagmite grows from it. What else do we- I brought a sample. I'm sure you've seen it before, but I brought some //limestone here, just in case. |
| 00:32:19 | //Is it the chalk? |
| 00:32:20 | It is not a chalk. It's the limestone. It's white limestone. Okay? |
| 00:32:29 | The next one on the list is the second to last. It's KMnO4. What does that mean? |
| 00:32:38 | Potassium manganate. |
| 00:32:39 | Potassium manganate. Potassium manganate. What is it- from the table? |
| 00:32:48 | Potassium permanganate. |
| 00:32:49 | Potassium permanganate. It is given in the table. Potassium permanganate. |
| 00:32:55 | Do you know what potassium permanganate- you may have heard it somewhere. What is it used for? |
| 00:33:02 | As a disinfectant and oxidizing agent. Write down, disinfectant and oxidizing agent. |
| 00:33:22 | Okay. The last one is? Please read the formula? |
| 00:33:31 | Calcium phosphate. |
| 00:33:33 | Calcium phosphate. Calcium phosphate. What is the common name for it? Do you know? |
| 00:33:41 | Apatite. |
| 00:33:42 | Well, the super phosphate is commonly used. It's a mineral, whose name is? |
| 00:33:48 | Apatite |
| 00:33:49 | Apatite. Phosphate, apatite. Phosphate and apatite. |
| 00:34:02 | I would like to return to the potassium permanganate. I brought one, for you to see. You probably can't see it. |
| 00:34:10 | I'm going to demonstrate- yes it dissolves into a purple liquid. |
| 00:34:19 | Let's take a look here, at this Petri dish and I'm going to place several crystals and pour in some water. |
| 00:34:39 | It is very interesting. |
| 00:34:42 | Very good. What kind liquid is it? You can all see that it's- |
| 00:34:49 | Pink color. |
| 00:34:50 | The pink liquid. This has disinfecting qualities. |
| 00:34:55 | In the civilian world, for example, kids are taught to use potassium permanganate, for disinfecting masks and so on. |
| 00:35:12 | Do you see it? We're not going to add anymore. You can see, it's a pink liquid. Okay? |
| 00:35:22 | I think we're done with the table. Why don't you study the table? The next topic is, the reaction. |
| 00:35:32 | I had prepared another table. I would like you to take a look at it. It is a very difficult theme. Can you see it? |
| 00:35:53 | Yes. |
| 00:35:54 | Okay. I'm sure, you're going to recognize the formulas. Let's go over it. Can somebody tell me what that is? The chemical formula. |
| 00:36:06 | Calcium carbonate. |
| 00:36:07 | Calcium carbonate. And what is this? |
| 00:36:09 | Calcium oxide. |
| 00:36:10 | Calcium oxide. Can someone write up the equation? How calcium carbonate turns into calcium oxide. Go up to the board and write the formula. |
| 00:36:22 | In the meantime, you'll write the formula into your notebooks. Write the formula into your notebooks. |
| 00:36:35 | CaCO3. |
| 00:36:38 | Here is number two. |
| 00:36:40 | It derives- so the arrow should be pointing, what direction? |
| 00:36:43 | Is the calcite created from that? What is created from that? |
| 00:36:48 | You need to reverse it. Yes. Okay. |
| 00:36:54 | I'm going to turn on the light, so we can have more light. |
| 00:37:03 | Okay. CO2 is created and what is CaO? |
| 00:37:07 | (inaudible). |
| 00:37:08 | Calcium oxide and what else? |
| 00:37:11 | Carbon dioxide. |
| 00:37:13 | Carbonated, yes. I would like to ask you kids, what is the common name for CaO? What is the common name for CaO? |
| 00:37:22 | We should see more hands up. We've already covered this material. |
| 00:37:27 | Okay. (Antolova)? |
| 00:37:30 | Burned lime. |
| 00:37:31 | It is burned lime. Very good. Okay. How about the second formula? Who can outline the second formula? Everyone should write the second formula. |
| 00:37:52 | The formula is Ca and we want to turn it into Ca(OH)2. How are we going to do that? How are we going to formulate the second equation? |
| 00:38:05 | Plus H2O. |
| 00:38:06 | Yes. Very good. Plus H20- Jan has said it. Okay. Plus H2O. What formula comes out of that? What will be the equation? |
| 00:38:14 | Ca. |
| 00:38:15 | What do we come up with? Ca(OH)2- but what else is there. Or no? |
| 00:38:23 | No, no. |
| 00:38:25 | Ca(OH)2. Ca, plus- |
| 00:38:29 | Ca(OH)2- |
| 00:38:32 | Ca(OH)2. Why don't you, (Dubravska), come up to the board and write it up. Hurry up. |
| 00:38:40 | You mean the entire formula? |
| 00:38:41 | Yes. |
| 00:38:46 | No. Not that. You're supposed to write the second one. Ca, which is lime. Ca plus H2O- as we've said. The result is? Ca(OH)2. |
| 00:39:05 | But something is still missing there. What is it? |
| 00:39:10 | Plus H2O. |
| 00:39:12 | Yes. Plus H2 is still missing. So, what is H2? |
| 00:39:18 | Hydrogen. |
| 00:39:19 | Hydrogen. We still need to fill in the formula with? |
| 00:39:24 | 2H2O. |
| 00:39:25 | 2H2O. Very good. Now let's concentrate on- formula number seven. Let's take a look at it. |
| 00:39:44 | The number seven formula is CaOH- |
| 00:39:48 | Number two. |
| 00:39:50 | Number two and the result is CaCl2. Let's write the formula. Which student- which student will come up to the board and write it? |
| 00:40:07 | Jakube! Why don't you come over here? |
| 00:40:09 | Me? |
| 00:40:10 | Yes, you. Jakube, why don't you write the formula which is on the sheet? CaCl2, CaCl2, draw an arrow- you can probably add something- |
| 00:40:26 | (inaudible). |
| 00:40:27 | Wait a minute. That derives from- so the arrow- |
| 00:40:30 | (inaudible). |
| 00:40:31 | Yes. Very good. |
| 00:40:33 | And it's, Ca(OH)2. |
| 00:40:37 | Number two. Okay. Jakube, I'm going to ask you and the entire class. What is Ca(OH)2? |
| 00:40:46 | Hydroxide. |
| 00:40:47 | Hydroxide and what's on the right side? |
| 00:40:49 | That's... chloride. Chloride. |
| 00:40:53 | What type? |
| 00:40:54 | Calcium... |
| 00:40:55 | Chlo... chloride. |
| 00:40:57 | Calcium. Very good. Now, why don't you tell me, what exactly is the calcium chloride. What are the substances in the //calcium chloride? |
| 00:41:04 | //Salt. |
| 00:41:05 | Salt. Very good. How is salt created? |
| 00:41:08 | The neutralization of acids and hydroxide- |
| 00:41:10 | Excellent. The neutralization of hydroxide and acids. So, why don't you write- what kind of acid? |
| 00:41:17 | HCl. |
| 00:41:18 | HCl. Very good. HCl. What else evolves out of that? |
| 00:41:31 | H2O. |
| 00:41:37 | H2O, yes. H2O. How do we complete the reaction? |
| 00:41:54 | 2H2O, yes. Okay? 2H2O, very good. Take a look. I would like to show you this experiment. |
| 00:42:05 | So, here we have calcium oxide or... |
| 00:42:08 | //Burned lime. |
| 00:42:09 | //Burned lime. We put out the lime. What do we use to put it out? |
| 00:42:15 | Water. |
| 00:42:16 | Water. What happens then? |
| 00:42:19 | Slaked lime. |
| 00:42:21 | Slaked lime or the chemical term is? |
| 00:42:23 | Calcium hydroxide. |
| 00:42:25 | Calcium hydroxide. How can we prove, that the calcium hydroxide is present? Does anyone know? |
| 00:42:32 | Some kind of indicator. |
| 00:42:33 | An indicator. Do we know of some kind of indicator? |
| 00:42:36 | The one you're holding. |
| 00:42:37 | This one here. And what do we call it? |
| 00:42:40 | (inaudible). |
| 00:42:41 | No. Can you name some indicators? |
| 00:42:45 | (inaudible). |
| 00:42:46 | Okay. Go ahead. |
| 00:42:47 | Litmus. |
| 00:42:48 | Litmus, very good. Any other indicators? I'm sure you've studied it last year. |
| 00:42:55 | Phenolphthalein. |
| 00:42:56 | Phenolphthalein. I have a phenolphthalein in my hand. I'm going to drop some into the liquid. Take a look. It turned- |
| 00:43:05 | Purple. |
| 00:43:06 | Purple. I have to- here it is. Can everyone see the color? |
| 00:43:12 | Yes. |
| 00:43:13 | Okay? Now, watch please. What do we have to do, in order to produce salt? |
| 00:43:20 | We must add the acid. |
| 00:43:21 | We need to add some acid. Good. What kind of acid will I pour in? |
| 00:43:27 | HCl. |
| 00:43:28 | HCl. Let's take a look. |
| 00:43:34 | When the salt is neutralized, what color will it be? |
| 00:43:42 | It's colorless. |
| 00:43:43 | It is colorless. You can see that it turned back to the original colorless stage. That's about it. Your homework assignments are? Your homework assignments are? |
| 00:44:01 | Please, write the formula from the diagram, which is in your book- look it up in your book. |
| 00:44:10 | The diagram, which we saw on the overhead projector. On page 118. Page 118 and you will complete the reactions. |
| 00:44:22 | Please write in your notebooks- we did reaction number five. Please, write down reaction three and four for now. |