Full transcript
0:00Hello . Today , we will be discussing the
0:02theory of chemical reactions in the
0:03field of chemical science . As mentioned
0:05in the previous lesson , chemical
0:06reactions in the field of chemical
0:08science can be classified into six main
0:09types . So , from now on , we will learn
0:11the mechanisms of these six types of
0:13reactions in order so that we can
0:15create chemical reaction equations for
0:17each . First , let's look at the first
0:19reaction , the three-postponement
0:21reaction . Furthermore , if we further
0:23divide these three-postponement
0:24reactions into two types ,
0:26neutralization reactions and weakly
0:27advantageous reactions . So , this time ,
0:29we will focus on the first half , which
0:31is to be able to write the reaction
0:32equation for the neutralization
0:34reaction . Now , let's get into the
0:35content . By the way , some of you may
0:38think that we covered neutral reactions
0:40in basic science . That's right , this
0:43time , I think there will be quite a bit
0:45of review . However , there are two main
0:48reasons for this . First , I would like
0:52you to review the basics together . And
0:55the second point , since this is finally
0:57a science class , I'd like to include
0:58some more detailed information . Even if
1:01you've watched the intermediate
1:02reactions in the Basic Science course ,
1:04I'd be happy if you could join me .
1:06Instead , I'll make this a short video ,
1:08so let's do our best together . So , the
1:11main focus will be on how to write
1:13intermediate reactions , but first ,
1:15let's review the 3 - cycle period . Okay ?
1:18First , let's review the definition of
1:20the 3 - cycle period . Yes . 3. Asit , Enki ,
1:23Base . Let's take a look at these . First
1:26, the definition of Alenews . In the
1:28definition of Alenews , 3 is something
1:30that releases H + . And Eki is something
1:32that releases OH - . On the other hand ,
1:35the definition of Brenset , which is a
1:37more recent definition , is something
1:39that gives H + to others , and Eki is
1:41something that receives H + . The reason
1:44for this definition is that , for
1:45example , in the Eki period , there are
1:47things like ammonia . When that reacts
1:51in the machine , we are mainly
1:53considering the aqueous solution , so
1:54even if it is not in the aqueous
1:56solution , we have defined it in this
1:58way to define a 3 - step reaction . Now ,
2:01let me briefly explain the content that
2:03follows , and also the content that will
2:05follow . In fact , understanding this
2:07Breistedt definition is a little
2:09important . The reason is that , in the
2:11last lesson , I think we discussed the
2:12importance of the three substances . And
2:15we talked about how substances and
2:16chemicals are in a theoretically
2:18unified relationship . This means that
2:20there is a possibility that acids and
2:22chemicals will be involved in this
2:24chemical reaction . And when oxides are
2:27involved , it becomes a little difficult
2:29to understand without this Breistedt
2:30method , so please understand that a
2:32little . And this is a slightly
2:36irrelevant point to note , but here , the
2:383 is intentionally written as ' A ' and '
2:40E ' in English , but from now on , I will
2:42write this 3 - E in abbreviated form .
2:46That's because from now on , well , it's
2:48a hassle to write 1 for communism , weak
2:50communism , strong period , weak period ,
2:53so sometimes , for example , if it's
2:55communism , it's written as SA from
2:57strong acid , or if it's weak acid , it's
2:59written as WA from weak acid , so please
3:02be careful about that . So please don't
3:05be scared if you suddenly start writing
3:07it that way . Yes . That's what I mean .
3:09Yes . Well , for now , well , it's a
3:10trivial matter , but for now , that was
3:12the definition of 3 and postponement .
3:15Now , let's look at some typical 3 and
3:17postponement . We've looked at hydrides ,
3:21ternaries , and hydrides so far , so
3:23let's look at this again based on that
3:25knowledge . Yes . So , let's start with 3.
3:29Yes . What comes to mind when you hear
3:31the word communism ? For example ,
3:34there's cyclic acid . Well , there's
3:37cyclic arithmetic , but let's use hx for
3:40now . So , what is this x ? It's a halogen
3:44, and among halogens , chlorine , um , br ,
3:47let's think of it as an astringent
3:49element . Of course , you can see that
3:52acids are strong , but as we learned
3:54when we studied hydrides , the further
3:57down you go in the periodic table , the
3:59larger the atomic radius , and the more
4:01likely it is to release H. In other
4:03words , it becomes 3 , which is stronger
4:05than HCL , so HBRHi , um , astringent
4:07hydrogen . Keep this in mind as well .
4:11And the next one . Um , the second one
4:13that comes to mind is , for example ,
4:15miscarriage . And the third one . This is
4:18also a weak compound that I want you to
4:20remember . For the time being , these are
4:22the compounds that I want you to keep
4:24in mind at the exam level . Make sure
4:26you remember this . And then , what are
4:28weak compounds ? Think of everything
4:31else as weak . Well , I'll write down
4:35some specific examples of weak
4:37compounds , but for example , in terms of
4:39hydrides , there are HF , refractor
4:41hydrogen , etc. Refractor hydrogen is
4:43the only weak compound among hydrogen
4:45halides , so you should remember this .
4:49And next , um , H2S hydrogen . Yes . This
4:52was also a weak calculation . I think we
4:54learned about this in hydrides . And
4:56next , just to be clear , let me give you
4:59one example from among the compounds ,
5:01um , H2CO3 monoacid , etc. Well , I've
5:03given a few examples this time , but if
5:05these aren't included , remember that
5:08it's basically a weak calculation . Yes .
5:10And next . Circular period . Let me write
5:13down what the co-flame was like . Ah ,
5:16it's a compound of an alkali metal . Yes
5:21. This is a little hard to see , but M ,
5:23this is derived from metal , but think
5:24of it as an alkali metal . Compounds
5:26such as lithium , sodium , and potassium .
5:30Of course , there are more than this ,
5:31but these are strong flames . And
5:36another co-flame that I want you to
5:38remember is a compound of an alkali
5:39metal . Yes . This is also calcium ,
5:44strontium , and barium . Is that okay ?
5:47And of course , the weak ones are the
5:49others . Yes . So , I'd like to give some
5:53specific examples here as well . Yes .
5:55For example , when it comes to hydride
5:58additives , of course , it's Group 15. Um
6:00, for example , ammonia . Well , there was
6:03also PH phosphine , but I won't go into
6:05that . Well , the only thing that comes
6:08up is ammonia , so don't worry about
6:09that . And then , when it comes to weak
6:11ones on the aquatic chemical side , well
6:13, we didn't deal with them in the
6:14aquatic chemical industry , but they're
6:16anything other than alkali metals or
6:18alkali metals . For example , aluminum
6:20hydroxide . Basically , you can think of
6:26most metallic aquatic chemicals as weak
6:28ones . Is that right ? Yes . So , basically
6:31, remember these as strong ones and
6:33remember that the others are weak ones .
6:36Yes . And here , I'd like to talk about
6:38one additional piece of knowledge , or
6:40rather , a small , important point to
6:42note . Um , this time I'd like to talk
6:45about miscarriage . By the way ,
6:48miscarriage , maybe you've all heard the
6:50rumor that a cerebral miscarriage is a
6:52weak birth . For those who haven't heard
6:55of it , let me briefly explain . As I
6:57said in the participation class ,
6:59miscarriage is a liquid at elevated
7:01temperatures . That's why it's possible
7:04to create a very concentrated
7:06miscarriage that's 98 % miscarriage .
7:08That's what we call miscarriage acid .
7:11So , what kind of state is miscarriage
7:13acid in water ? There's almost no water .
7:16Now , let me compare this to the
7:18definition I gave earlier . In order for
7:21this to become 3 , H + needs to be
7:23released in the water , but there's no
7:25water at all . H + is actually in the
7:29form of an oxonium ion called H3O + , so
7:32it's difficult to electrolyze this H +
7:34unless there's water to push it . So , in
7:38terms of pH , miscarriage acid is
7:40actually completely incapable of
7:42electrolyzing . In reality , you want to
7:44electrolyze 100 % with symbiosis , but
7:46there is no water , so electrolysis
7:48cannot be done at all and the pH does
7:50not rise easily . That's why I think
7:52there are sometimes teachers who teach
7:54that symbiosis is a weak production ,
7:56but personally , I think it's better to
7:57have a symbiotic mindset even if
7:59symbiosis is used . What I mean is , of
8:02course , this one doesn't reward H +
8:04very much , but it has an incredible
8:06ability to give H + . So , in terms of
8:10Brønstedt's 3 , this one is a strong 3.
8:12It just happens that the recipient
8:14isn't in the water yet , so this one
8:16doesn't show any approval . So , for
8:21example , if you put E in symbiosis with
8:23symbiosis , it will react explosively ,
8:25and in the end , its ability as a 3 is
8:27quite high , so , well , in order not to
8:29lose the image of the reaction , I think
8:32it's important to remember that even
8:34symbiosis is strong . So to be precise ,
8:37I think it would be best to think that
8:39PH cannot be used to measure pH . Well ,
8:41ammonia is the same . Ammonia in the
8:44form of ammonia does not emit OH - in the
8:46first place , so it is counted as an OH -
8:48, and ammonia in the form of ammonia ,
8:50which cannot be measured by PH , is
8:51normally counted as an OH - , so you can
8:53think of it as something close to that .
8:55Yes . Well , I know I may go into too
8:57much detail for a science-oriented
8:58audience , but these were just a few
8:59minor points to keep in mind . Anyway ,
9:01getting back to the topic , please make
9:03sure you fully understand the
9:04definition of a 3 - cycle and the typical
9:063 - cycles . Yes . Now that we've reviewed
9:11to some extent , I'd like to do a more
9:13detailed explanation of how to write
9:14reactions , a science-oriented version .
9:18Well then , let's write on the
9:19blackboard . Now , let's review how to
9:22write reaction equations , including
9:24some new content as well . Yes . First ,
9:27I've written down the key points here .
9:29It's the balance between the H + and OH
9:31- . This is exactly the same as what we
9:33learned in basic science . It's about
9:35counting the number of H + and OH - and
9:37making them equal . And this time ,
9:40there's a little extra content . I wrote
9:43that when a triangular object appears ,
9:45we should formally consider adding
9:46water . Let's look at a concrete example
9:49to see what this means . This time , I'll
9:51look at three concrete examples , so
9:52please watch until the end . The third
9:54one is the most important . So let's
9:56look at the first one first . Yes . We
9:58added CO2 to a certain amount of NaOH
10:00aqueous solution . Yes . The problem this
10:03time is that CO2 appeared here . Yes .
10:08And CO2 is , of course , CO2 , and as we
10:10learned in the triangular object class ,
10:12if we added water to this , it would be
10:15a simple acid . Since that simple acid
10:18and CO2 are in a formal relationship ,
10:20this becomes 2/3 . I think we learned
10:23that . And let's go back to the point
10:25again . When an acid appears , what does
10:27it mean to add water to it ? In this
10:32case , CO2 is reacting here , but let's
10:34think of it as if it had reacted once
10:36after it had been added to the water
10:38solution . Well , this reaction is
10:42actually a single reaction , so it's
10:44perfectly natural to think of it as
10:46reacting after it had been added to the
10:48water solution . So let's write it down
10:50here . First , we've already learned how
10:54to write this when CO2 enters the water
10:56and combines with it . Then , let's think
11:01about the H2CO3 and NaOH that were
11:03created in this way . From here on ,
11:05we'll naturally follow the rules . Let's
11:07think about the balance between the H +
11:09that this one produces and the OH - that
11:10this one produces . I'll just write this
11:13right away , but H2CO3 produces two
11:15parts . In order for the 1+ and the
11:18middle part to occur exactly , we need
11:20two parts of NaOH . So these react , and
11:23then the middle part reacts like this .
11:27Yes . Is that okay ? When two H + and two
11:30H - join together to form two water
11:32molecules , the rest dissolves like this
11:34. Yes . Once you have two reaction
11:37equations like this , this is the last
11:39step . Let's add these together . When
11:42you create equations for oxidative
11:43reactions , I think there was a similar
11:45addition method , and you add them
11:46together like this . Of course , you can
11:48eliminate the overlapping ones . You can
11:52eliminate the overlapping ones on
11:53opposite sides like this . Then , add the
11:56remaining ones below to complete the
11:58reaction equation . Yes . That's it . Well
12:01, the content may be a little new , but
12:03what you're doing is a combination of
12:04what you practiced when you learned
12:06about three additives and what you
12:07learned about intermediate reactions ,
12:09so I don't think there's any problem at
12:10all . And I'd like to practice two more
12:12things , so let's delete this one for
12:14now and look at two more specific
12:16examples . Now , let's look at the second
12:18specific example . Yes . It's a circle
12:20calculation of the amount of
12:21sufficiency . Let's see what happens
12:23when we add CAO , calcium oxide , to this
12:26. First , of course , we're curious about
12:28this CAO trigonometric compound . Let's
12:30process this . Since we just did it ,
12:32let's do it quickly . Yes . It's CO . This
12:36is a trigonometric compound , so let's
12:38first consider it formally by adding
12:40water . Yes , when water is added to this
12:42, it becomes like this . Yes , if we
12:45write it like this , it becomes a
12:47hydroxy compound , so let's neutralize
12:49this hydroxy compound and the cyclone .
12:53I'll write it first , but for COH2 , if
12:55there are two parts of this , it can be
12:57neutralized with two parts of OH - , so
12:59it becomes 2HCl . Now , let's write the
13:03rest . Yes . I've written it like this .
13:06All that's left is to add the variable
13:08sides . I'll do it again carefully , but
13:11yes , let's delete the overlapping ones .
13:14And here , water is also overlapping , so
13:16if we delete it , the rest will be
13:18written as usual by adding them . Yes .
13:22It looks like this . It doesn't really
13:24matter whether the acid is positive or
13:26the ternary compound is the current
13:28line . Just write it like this . Is that
13:30okay ? Then let's look at the last third
13:32example . Yes . Well then , let's look at
13:36the third one . This also writes the
13:38reaction equation . Yes . Well , I'll
13:40write it . Please follow along as if it
13:42were a review . First , SiO2 . If you
13:46formally add water to SiO2 . Yes . Then ,
13:49what will happen is , of course , H2Sio3 .
13:53Yes . I think this was written in the
13:55aquatic compound section when the
13:56ternary compound was added . Is that
13:58okay ? Then , since this is in the 2 : 3
14:00state , all we have to do is consider
14:02the neutralization reaction with it . If
14:05there are two for one H2SIO3 , the
14:07neutralization is complete , right ? And
14:11what comes out is two waters and the
14:13rest , so we add them like this . Yes .
14:16It's exactly as the back is Ollie said .
14:18All that's left is to add them together
14:20by changing the sides . Of course , if
14:22you erase the overlapping part , you'll
14:24also erase the water , which will result
14:26in this . Yes . Is that okay ? I think
14:31I've followed the steps . However ,
14:33there's just one thing to note here .
14:36It's a bit of a technical point , but
14:37I'll mention it anyway . Let's review
14:40this from 01 again . Yes . CO2 has been
14:44dropped into NaOH . It looks like it's
14:48reacting when it combines with water .
14:51On the other hand , this one also adds
14:53CAO powder or a solid to HCl . When it
14:57combines with water , it becomes this ,
14:59and it looks like it reacted . How about
15:02this ? For example , it's written as if
15:05SIO2 has entered water , formed this
15:07shape , and reacted . Just remember this .
15:13SIO2 is a crystal , right ? To be more
15:16specific , for example , water droplets
15:19and things like that are SIO2 . Is that
15:21okay ? Or it could be contained in glass
15:23. In this way , no matter how you look
15:26at it , this thing can't actually bond
15:28directly with water . So , in reality ,
15:31this two-step reaction isn't actually
15:33happening . That's why I've been saying
15:37" formally " all along . As you can see ,
15:40the reaction that's happening is a
15:41neutralization reaction between a
15:43positive ternary additive called SiO2
15:45and a positive ternary additive called
15:47cyclohexane , so there's no problem at
15:49all . In the process of writing the
15:51reaction equation , it's much easier to
15:52write the reaction equation if you
15:54formally add water and think of a
15:55reaction that doesn't actually happen
15:57as having happened . So , even if it's an
15:59unlikely reaction , let's just write it
16:01down like this for now . Is that okay ?
16:04Yes . As you can see , this is a bit of a
16:06nerdy point to note , but things like
16:08this do happen , so please be careful ,
16:10even though this is strictly for
16:12science students . On the other hand ,
16:13there are no more difficult questions
16:15than this when it comes to the reaction
16:16equation for the intermediate reaction ,
16:18so I think it would be good if you
16:19could write it down properly up to this
16:20point . Well , I apologize for repeating
16:23myself , but if you don't understand the
16:24phenomenon , if you don't understand
16:26that you're doing something that isn't
16:28happening , you might be surprised when
16:30the time comes , so I'd appreciate it if
16:31you could just keep that in mind and
16:33leave it as a point of caution . Okay ,
16:36so that's it for this time . I think the
16:39video ended up being quite short , but
16:41that was how to write a neutralization
16:43reaction equation . I'd be happy if you
16:45could just keep it in the form of rules
16:47and exceptions . Okay . So , this is how
16:50to write the first half of the turn
16:52postponement reaction , the middle
16:53reaction . Please listen carefully so
16:55you can do this . As a preview for the
16:57next episode , next time we'll be
16:59looking at the weak-weak phase , the
17:00favorable reaction . Actually , that's
17:02what I want to focus on the most this
17:04time . In fact , 3 and Iki can cause a
17:06weak-phase favorable reaction in
17:07addition to the neutralization reaction
17:09. And in that direction science , it's
17:11no exaggeration to say that this
17:12weak-phase favorable reaction on the
17:14latter half of the line is actually
17:15more important , so let's work hard
17:17together next time so that we can do
17:18this properly . So , if you enjoyed this
17:20lesson even a little , please subscribe
17:21to the channel , leave a comment , and
17:23give it a thumbs up . Well , that's all
17:24for today . Thank you for your hard work
17:26.