I went to Wikipedia,

and I decided to pick up the definition

for an equivalent there. And I actually didn’t

find it too useful, but there are some things

that I wanted to point out. So it says, “The

equivalent is formally defined as the amount of a

substance which will either react or supply with one

mole of hydrogen ions in an acid base reaction;

or do the same with one mole of electrons in

a redox reaction.” So all I’ve really

figured out so far– I was a little confused

when I read this– but I figured out

what they are saying is that an equivalent

is basically some amount, some number, right? So let’s start there. So when someone says, hey, how

many equivalents do you have? I know that they’re

talking about some number. So equivalent is equal to– and

this is for some ion, right? So for some ion of my

choosing an equivalent equals some number. And usually that number

is in terms of moles. So some number of

moles that I need, so needed to balance something. I’m actually

balancing some charge. So balance the charge of

an oppositely charged– so an opposite charge–

opposite monovalent. Actually, I should even add,

balance the charge of– I guess I can add without

erasing– charge of one mole– that’s

actually really important– of an oppositely

charged monovalent. OK, so let’s jump

into an example, because I think that will

clear up any confusion that you may have to this point. So let’s say we’re talking

about, for some ion, let’s say we pick potassium, OK? Here’s our potassium. And I’ve got to balance out

one mole of an oppositely charged monovalent. So this is my little line

demarcating the other side. So on the other side let’s

say we have chloride. And chloride is

oppositely charged. It’s negative, right? And it’s a monovalent. It’s not negative

2, or negative 3. It’s just negative 1, right? So we’ve got, let’s

say a mole of these, because the definition

I wrote up just said that I needed a mole

of an oppositely charged– and as I’m writing

this up, I’m realizing, and I hope you are,

too, that there’s no way in the world I can

write up a mole of this stuff. There’s no way, right? So let me just get

the point across that, just imagine that there are a

total of this many– 6.02 times 10 to the 23rd chlorides. Because that’s

really the question. How many potassiums do you

need to balance out the charge from all of those chlorides. And that’s too big a

number, too big a number to write out in any easy

way, other than to say, well, maybe you need some

number of moles of potassium. And that’s why I wrote that

right into the definition. So let’s figure this out. So we know that potassium

binds one to one with chloride, right? We know that’s what happens. So when potassium’s

floating around, and it’s gonna

bump into chloride, it’s going to go one to one. So we know that

for one chloride, we’re going to

get one potassium. And so that means that

for one mole of chlorides, we’re going to get

one mole of potassiums bound to them, right? And that’s going to balance

out the charge perfectly. So if someone says, well,

how many equivalents do you have for potassium? That seems like a

very simple answer. Well you say, OK,

well, one equivalent would then be one

mole of potassium. Or you could even rephrase it. You could say, well, in

one mole of potassium– and this is how people

usually use the phrase. They say, well, 1 mole of

potassium equals 1 equivalent. So I know that’s the same

thing flipped around, but that’s how people

usually state it. So now let’s do a slightly

more challenging example, and you’ll see where this

becomes a little different. So instead of potassium, let

me jump into another one. Let’s do calcium. Calcium– so there’s a plus 2. And same thing as before. I’m going to have to choose some

oppositely charged monovalent. And I’m going to pick the

same one, because this still is oppositely charged. I just needed some negatively

charged monovalent, and chloride suits our purposes. And we know, just as before,

we need a whole mole of them. And so if that’s the

case, how many calciums will bind to a chloride,

and vice versa. How many chlorides

will bind to a calcium? So let’s imagine we have a

little chloride and calcium party, and they can

meet each other. Well, what’s going to

happen is, that you’re going to have a calcium

there, and a chloride there, and a chloride there, right? Because this will come here. This will come here. And they’re going to

basically bind and make this. They’re going to make CaCl2,

because the chlorides are only one negative charge–

actually, and this is two positive charges. I’m flipping around my

negatives and positives. Sorry about that. There we go. Negative, negative, and plus 2. So you know that for

every one calcium, you’re going to

get two chlorides. So let me write that

out very clearly. So for every one

calcium– or actually I can write for

every two chlorides you get one calcium, right? And that means that for every–

if I divide both sides by 2– for every 1

chloride, I basically needed a 1/2 a calcium. And that’s not how

we think about it, usually, because it’s hard

to imagine 1/2 a calcium. But at least the

math works out there. And so if I’m talking

about one mole of chloride, then I’m left saying, well, then

I have a 1/2 a mole of calcium. So far so good. And so, then, 1 equivalent,

going back to our definition, equals 1/2 mole of calcium. And I said that we could

flip around the equation, and we can. We could say, well,

then 1 mole– now all I did is multiplied both sides

by 2– 1 mole of calcium– I’m not writing clearly right

now, sorry– 1 mole of calcium equals 2 equivalents. So there is how people

usually phrase it. They’ll say, OK, well,

how many equivalents do you get for 1

mole of something? And so here you would

say the answer is 2. And so I just want to

point out something to you, which is that we

kind of did this a long way, but here is a quick

and dirty way. You could say, well, I know

that calcium is divalent, and we know that

potassium is monovalent, and here is kind of an

interesting pattern that’s emerging, right? As this Ca plus 2 emerged, we

got 2 equivalents out of it. Let’s test this

with a third one. Let’s just see what we get if

we use, let’s say, nitrogen. So let’s do nitrogen. Nitrogen is negative 3. And I have to

create my boundary, and on the other side, I

need some oppositely charged monovalent. So there’s a monovalent and it’s

opposite– here’s monovalent, check, and it’s

oppositely charged, check. Opposite. Opposite of the negative, right? So check, check. It meets our requirements. And I need a mole of them. So I have to draw

out a mole, and you know there’s no way I can

do that, as I said before. And so just imagine

1 mole of these guys. And the question,

again, is how much nitrogen do I need to

balance all this out? And I’m gonna just

underline in red the clue. So here’s the clue. And let’s now actually

go through the steps of figuring it out

kind of the longer way. So let’s imagine you have a

nitrogen here, negative 3, and it’s going to be at this,

let’s say, cocktail party, and it meets some protons. And in this case,

3 of them come by. So it’s going to

form NH3, right? If we say 3 protons

then come together with 1 nitrogen, which

is what we just said, then I can divide

both sides by 3, and I can see that 1 proton then

comes with 1/3 of a nitrogen. So far so good. And I can then even go on to

say 1 mole of protons, which is going back to our definition,

would be balanced out by 1/3 of a mole of nitrogen. And if that’s the

case, then I can say, well, 1 equivalent equals 1/3

third of a mole of nitrogen. And I’m going to flip this

around, just as we did before. I could say, then 1– let me

change that– I could say, then 1 mole of nitrogen

equals 3 equivalents. And remember, we underlined

that little 3 in the beginning, and I’m going to

underline it again. And now you can very clearly

see the pattern that’s emerging. So you can see that any time

you look at the cation or anion that you’re talking

about, if you look at the number–

like if it’s, let’s say, magnesium, that’s 2 plus,

or calcium is 2 plus– then you can know immediately

that that probably means, if you did the work

the long way like we just did, that the equivalents are going

to work out to the same number. So nitrogen has 3 equivalents. Magnesium or calcium

have 2 equivalents. And potassium and chloride,

they all have 1 equivalent. So that’s what equivalents mean

in terms of the moles needed to balance out a charge

on the opposite side.

You might create a video to explain how this would apply to dosage information that is given in milli equivalents.

Thank You. This clarified why the equation is Equivalents = moles * valence.

Hopefully I will one day understand why we use Equivalents.

Are you a lefty?

thats the best !!!! thanku sooooooo much !!!! oh really ! this means. A LOT. to me !!!

Thank you so much for the help, you're super easy to follow and understand. My book goes into little detail and I was pretty confused, but it's actually pretty elementary. Thanks!!!!!!

great explanation! you are right … the Wikipedia explanation was useless

wow i didnt get nothing!!!

Thanks. Very clear explanation

Is an equivalent the same as normality?

Thanks a lot!!

thanks dawg,

What if you are given the concentration of say CaCl2 and u are to find the concentration of Calcium, CaCl2 has no charge but Ca has a charge of plus 2

welp…..wikipedia is pretty useless

what if on the other side we don't have a monovalant, the equivalent of a substance will be a variable r8? the equivalent of calcuim will not always be 2. it wud only be 2 if v hav a monovalent on the other side…

very bad explanation. not clear at all.

I was much less confused before I watched this video.

hidemya

it's calcium (Ca2+) stop calling it potassium

why dont you show of NH3CO2H ? idont know how to calculate the equivalent of this

you dont deserve my subscribe! slow!

What is equivalent weight ?

than what about equivalent mass??

Glad I wasn't the only one getting way more confused when watching this lol.

thank god …I didn't study here

Nice yrr, clearly understood

perfect thanks

THANK YOU!!Thanks for clearing very basic concept

This is the best explanation I've ever come across…..thanks a lot

Thanks a lot. I feel lot more comfortable now.

we calculated number of moles of K+ ion (for example) to neutralize an oppositely charged monovalent. But how do we calculate if we were to K atoms (neutral) in place of K+ ions? Then we will need infinite moles, right?

Very basic explanation

great explanation

I understand how it works but THE BIG BIG PROBLEM is that I really don't know why they invented this term in the first place?? what is the purpose of it?? we have Moles and other units so what info does this Unit provide that is too important to deal with it in daily bases? need to clarify

I wanna know about gypsum equivalent

Superb explaination

Please help me with this sir. Why is 1mol of h+ = 1eq?? Why not 1mol of n3- = 1eq and 1 mol of h+= 1eq??

best of all thank you cleared my concept #equivalent is just number @ requirement 1 mole oppositely charged monovalent ion or just hit the valency….

Em…so basically the ionization = the Eq?

Thankew U r better than wiki

best explanation

what is the equivalent weight of triethylamine

Don't know why its important to learn this but at least I understand it

THIS WAS SO CLEAR!!! Thank you!!!!!!!!!!!! 🙂

So it's literally just a mol to mol ratio? Why did they give it a stupid and confusing name?

This is so easy to understand!!! Thank you so much!

Thanks this really helped 👍

Thanks a lot ❤

is it constant for an element

super useful!

Thank you. Great explanation

Thancc boomer.

Thank you thank you I was struggling to understand what equivalent means but now I have a better idea

Nice explanation. Thank u

Simply put … an equivalent = a mole of charge .