00:00 Good day everyone, my name is Adekunle, I am teaching you chemistry and the topic we have now

00:19 is chemical symbols, formulae and equation. Chemical symbols, formulae and equation. What are

00:28 chemical symbols? The symbol of the image represents an atom of the element and there are three ways

00:34 in which the symbols are derived. The first is the use of their phase letter, like hydrogen,

00:40 carbon, sulfur. Hydrogen, we use the phase letter H, carbon, we use the phase letter C and

00:46 sulfur, we use the phase letter S and some other examples like that. Combination of the

00:51 phase, the next is, convolution of the phase letter, written in capital and one other letter

00:57 from the name of the element, written in small letter. For example, helium, H, E, neon, N, E,

01:03 silicon, S, I, chlorine, C, E, capital letter and then another letter from the name of the element

01:11 followed with small letter. The next, where we are named chemical symbols, is derivative from

01:18 the last name of the element, E, G, sodium, from natural, ion, from pharaoh, civa, from agentum,

01:26 mercury, from adrageum and root from arom. Chemical formulae, the formula of the compound contains

01:34 the symbols of the different elements that combine chemical to form the compound, E, G,

01:40 calcium carbonate, or calcium triadal carbonate for. Whereby, it contains carbon and it contains

01:47 calcium, one atom of calcium carbon and then three atoms of oxygen. The next we talked about is

01:55 radicals. What are radicals? They are group of atoms carrying charges that still keep the identity

02:01 and react as a single unit. The phase is triosonitroid 5 ion or triadal 5 radicals. The

02:09 next also is triosocabonates for radicals, CO3, 2-minus, the next C and O3-minus, OH-minus,

02:18 M and O4-minus, NH4-plus, ACO3-minus and so on. The following are names of some of some compound

02:30 containing radicals. For example, calcium triosonitroid 5 contains two radicals of NO3.

02:39 We have NON3 which is named sodium triosonitroid 5. It contains one radical and then we have ion3

02:47 hydrozyme. It contains three radicals of OH. The next is our DIY rights chemical formula.

02:55 How do I write them? The following steps are followed, are to be followed. The first you write the

03:01 symbols for the elements, after which you write the oxidation number of valency to the right

03:06 and above the symbol. We write the symbols in touching in oxidation numbers and write the numbers

03:13 below and to the right of the symbols, omits the charges. You don't need the charges.

03:19 O's addition number and valency. Valency is the combined power of any element. Why O's addition

03:25 number is the charge it carries. By this definition, you get to understand that valency has no charge

03:31 and it's often considered a formula of compounds. Why O's addition number carries what? The charge.

03:37 O's addition number carries the charge and for metals, O's addition number is positive.

03:43 Why for non-metas, it is negative. Valency is usually obtained from the number of electrons

03:48 present in the outer motion of an atom. How do we determine that? For metals, which

03:55 most times belong to group 1, group 2 and group 3D, they actually have their valency to be the

04:01 elements are the atoms shell, the valence electrons, which is positive, 1, 2, 3, usually.

04:08 Why for non-metas? You just operate group 8 from whatever they have at their valence electron.

04:17 The O's addition number of valency is usually plus 1. These are the exceptions. O's addition

04:21 being plus 1 accepts in metal hydride whereby it is what? Minus 1. As we see in sodium hydride,

04:27 and in calcium hydride, sodium hydride, and in calcium hydride, sorry. Also, the O's addition

04:33 number of oxygen is given as minus 2, except in peruzide. For example, hydrogen peruzide,

04:39 the O's addition number of oxygen there is minus 1. And in O's too, potassium peruzide, sodium peruzide,

04:46 whereby we said the O's minus 1, examples of metals and non-metas and their radicals.

04:52 Giving the O's addition number and giving the valency. Potassium plus sodium, potassium plus 1

05:00 by the valency is 1. You can see there in this table that we have the valency not to have any

05:07 charge before it, why the O's ask whether it's positive or negative. I hope you can see the

05:14 board very well. Example, write the chemical formulae for the following compounds. The first is

05:21 ammonium triosunatrid 5. Follow me as we show you, as I show you how to go about this. Ammonium

05:28 is ammonium is NH4 plus. And triosunatrid 5 is taken from triosunatrid 5 ion and O3 minus.

05:42 When you combine these two, ammonium be taken the charge on triosunatrid 5 ion, Y triosunatrid 5 ion,

05:52 be taken the charge on ammonium, but without considering the sign. Actually this is plus 1,

06:01 why this is minus 1? Just take the number. So you have NH4, as also the right one, but there's no

06:08 point in doing that. Since it's just 1, if it's 2, I'll have to bracket it. And then you write

06:13 N O3, carrying this plus 1. This is the formula for ammonium triosunatrid 5. The next is potassium,

06:21 tetra-ososophage cis. Potassium K, K plus. Tetra-osophage cis is SO4 2 minus.

06:33 Join them. Potassium, you first write potassium. And then the number are both triosunat tetra-osophage

06:42 cis, which is 2. Then you write tetra-osophage cis. And the number before on top of potassium,

06:50 which is 1. Because it's 1, I don't need to put it there.

06:57 The third one, potassium is 2 plus, potassium 2 plus. Hydrozyde is OH minus,

07:06 potassium, combined then, potassium, we carry the minus 1 here. I was supposed to write 1,

07:11 but there's no point in doing that since it's 1. If it's 2, I'll need to write it. Then you write the OH,

07:23 potassium OH, then the 2, on top of potassium, you put it there. Because I need to, because I'm dealing

07:31 with a radical, I put brackets. So the formula is C-A-O-H2 for potassium. Hydrozyde. I believe you

07:40 understand that example. The next is, how do I name? How do I name compounds? How do I name

07:49 formulas? When they stand that way of naming is IUP, which is the International Union of Pure

07:56 and Applied Chemistry. The system is also shown by a naming compounds. The sum of the

08:01 assumption number for a compound is zero. Without a radical, it is zero. But if it is a radical,

08:07 the sum would be equal to the value of the radicals. We are still going to show examples on that,

08:12 so that you understand very well examples.

08:19 Capulate, the oxidation number of sofor in N-A2-SO4, which is sodium t-troubles of its 6.

08:32 Sodium t-troubles of its 6, the way that I pronounce it, you will discover that I've given you

08:36 an int to the answer. What is the value of sodium? Sodium is plus 1. Sodium is plus 1.

08:48 Sofor is what I'm looking for. Oxygen is minus 2. Let's just go with this. 2 into bracket

08:56 the one of sodium plus 1 plus x. Sofor plus 4 into bracket oxygen minus 2 is zero. Like we said,

09:08 for ordinary compounds, the summation is zero. 2 times 1, 2 plus 4. 4 times minus 2 is minus 8,

09:18 equals to zero. Sofor take our collect-like terms, take the numbers to the other side minus 8 to the

09:24 other side of the composition. Minus R plus 2 here, we come negative. I don't know if you have

09:30 8 minus 2 to give us plus 6. Therefore, we can see the formula is, the name is

09:36 sodium t-troubles of its 6. The next is calculate the oxygen number of chlorine in this radical,

09:45 in this radical chlorine. I'm looking for it plus 3 into bracket oxygen minus 2. We give me the value,

09:55 equals to the value of the radical is actually minus 1. Compared to this ordinary compound,

10:02 I don't know if we sometimes get it equal to zero. We are equating it to the value of the

10:09 radicals. So we have C L, 3 times minus 2 is minus 6, equals to minus 1. Take minus 6 to the other side

10:18 of the composition, and then missing with minus 1, we have 6 minus 1 to give us plus 5. So we can

10:26 gladly see that our formula is tri-ozo-chlorate-5. The next thing we look at is loss of chemical

10:38 combination. The first law is law of conservation of mass, or matter we say that during chemical reaction,

10:44 mass canada be created, no destroyed. If you want to see mass, mass canada be created, no destroyed.

10:50 And the next law we talk about, states the law of definite proportion, or constant composition,

10:54 we say that all pure samples of the particular chemical components contain similar elements

10:59 combined in the same proportion by mass. And the next is law of multiple proportions. We say that

11:06 if you eliminate it and be combined to form more than one chemical component, then the various

11:10 mass of it, which combined separated fish mass of B, are in simple oh number ratio, chemical

11:17 equation. Chemical equations are representation of chemical reactions. In terms of symbols and

11:24 formally of the elements and compounds involved. By the time we see chemical equations, it's different

11:31 from mathematical equation. Mathematical equation can simply be represented with

11:37 conservation by equals to that for mathematical equation. Yeah, in chemistry that's why it is

11:42 stated that chemical equation, different for mathematical equation that you are conversant with,

11:47 yeah, we used arrow pointing to its side, except for reversible reaction, whereby you also have

11:54 an arrow pointing backwards, forward and backward for reversible reactions, why for ordinary

12:00 reactions, just have one single arrow pointing forward. And in chemical equation, we have,

12:05 on our left side, we have reactant on the right side, you have the product as we see above

12:12 A plus B represented by reactant to equal to C plus D, which represents the product.

12:18 For chemical equation to actually represent a chemical reaction, it must be balanced.

12:24 It must be balanced. That is, the number of atoms at the left hand side must be equal to the

12:29 number of atoms at the right hand side. What are the things to consider in balancing equation?

12:34 What are the things you need to consider when you are balancing equation? You don't balance

12:37 the subscripts, the elements or the formula remains the way it is. And then common gases like

12:43 hydrogen, oxygen, nitrogen, and chlorine, which are atomic, in the short, you must represent them

12:48 the way they are. Not that you write H, or O, or N, it must be H2, it must be O2, it must be N2.

12:56 Elements are the sodium, potassium, copper, and ion. In their free states,

13:01 are also represented by their chemical symbols. They don't change. You don't say K2,

13:06 you don't say N2, it should be ordinary, it will be ordinary key, it will be ordinary sodium,

13:12 which is N8. And then in simple chemical reactions, radicals would be main words.

13:18 On change, radicals, it's main, on change. If it's OH minus, it will see the OH minus.

13:23 If it's S of O2 minus, it will still be S of O42 minus. For example, less balances.

13:31 Less balance. The combustion of ammonia in A. What is combustion? Combination means that

13:36 it has to do with reacting with oxygen. Ammonia N is 3. Ammonia N is 3 plus oxygen representing A.

13:46 To actually give us N O plus H2O. How do we balance this? The first step, you balance the hydrogen.

13:57 And now you balance hydrogen. Check the atom count. You have 3 hydrogen A, you have 2 hydrogen A.

14:04 The best I can balance this is, I put 2 A. Like I told you, you don't balance down. You don't

14:10 balance by the soft grit. You balance only from the top. And then to balance hydrogen, H3A,

14:17 let me put 2 A. So that we have 2 times 3. And A, I put 3. So that I have 3 times 2.

14:23 Making sure that hydrogen is balanced 2 times 3, 2 times 3 on the right hand side and 3 times 2 on the

14:29 front side. Hydrogen is claimed. The next I need to balance is nitrogen. How do I balance nitrogen?

14:36 2 nitrogen A and now I'm having one nitrogen A. I actually add, I should put 2 before N O. So

14:44 that nitrogen with balance, nitrogen with balance A. My hydrogen is balanced, my nitrogen is balanced.

14:49 The next I need to balance is oxygen. How many oxygen do I have now on the product side?

14:56 I have 3 A, 2 A, making 5 oxygen. And normally I have an O2 A. How am I going to balance this?

15:04 5 over 2. 5 over 2 implies that this is 5 over 2 times 2. Which also implies that we have 5 oxygen

15:15 corresponding with what we have here. But we can't leave our answers like this. Then you multiply

15:20 to, but the denominator which is 2. By so, do you have 2 times this to give us 4 ammonia plus 5

15:28 2 times this will remove the denominator. So you have 5 oxygen. And then 2 times this will give us

15:36 4 N O, nitrogen 2 Z. Then you have 2 times this to give us 6 water. With this, you can check whether

15:51 your equation is balanced or not by doing atom count. On the return side, on the return side,

16:03 my nitrogen, my hydrogen, and my oxygen. On the return side, how many nitrogen do I have?

16:11 I have 4 nitrogen. And on the product side, how many nitrogen do I have? I have 4 nitrogen.

16:17 With hydrogen on the return side, I have actually have 4 times 3. 4 times 3, which is 12.

16:27 And on the product side, I actually have 4. I have 6 times 2, 6 times 2, hydrogen. And that's

16:35 what we give me 12. You can see it's balanced. The last but not the least, which is oxygen 502.

16:42 5O2 means 5 times 2. 5 times 2, which is 10 oxygen on the return side. And on the product side,

16:50 I actually have 4 oxygen like this plus 6 oxygen like this. So 10. You can see very clearly that

17:01 our equation is fully balanced. Assignment. Balance the following chemical equations, H2SO4,

17:09 plus UDOMI RUZI to give us N2SO4 plus H2O. Then the next ion plus chlorine, gas to give us

17:18 ion 3 chloride. The next KOH plus CO2 to give us K2 CO3 plus H2O. And then the next is C6 H2FO6 plus

17:29 O2 to give us CO2 plus H2O. And the last is KCLO3 to give us KCL plus O2. All the equations are

17:39 no balance. You need to balance them. Thank you for watching. My name is Adi Kuli, Senior Sine.