The Mole Bozeman Science English English (auto-generated)

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Hi. It's Mr. Andersen and this is chemistry essentials video 3. It's on the

hi it's mr. Andersen and this is chemistry essentials video 3 it's on the

mole. The mole is an incredibly important term. But remember it's just a number. It's

mole the mole is an incredibly important term but remember it's just a number

Avogadro's number. Why is it important? Well it allows us to deal with the massive number

it's Avogadro's number why is it important well it allows us to deal with

of atoms that are found in matter. This is one of my favorite demonstrations. You take

the massive number of atoms that are found in matter this is one of my

a five gallon jug. Put a little bit of alcohol in it, like ethanol. And when you light it

favorite demonstrations you take a 5 gallon jug put a little bit of alcohol in it like ethanol and and when you

you get this huge Whoosh, and this huge combustion of the ethanol. If we were to write out the

light it you get this huge wolf and this huge combustion of the ethanol if we

formula, it looks like this. Why am I talking about this when I'm talking with moles? Well

were to write out the formula it looks like this why am I talking about this

remember those coefficients that you write in front of the compounds in an equation like

when I'm talking with moles well remember those coefficients that you write in front of the compounds in an

this represent the number of moles. In other words how many massive number of atoms are

equation like this represent the number of moles in other words how many massive

interacting. So it's really important when we deal with chemistry to understand what

number of atoms are interacting and so it's really important when we deal with

the mole is. And the mole is simply Avogadro's number. It's a number. It's 6.02 times 10

chemistry to understand what the mole is and the mole is simply Avogadro's number it's a number it's 6.02 times 10 to the

to the 23rd. Where does that number come from? It's derived from the number of atoms in 12

23rd where does that number come from it's derived from the number of atoms in

grams of carbon 12. But it just gives us a usable amount of material that we can work

12 grams of carbon-12 but it just gives us a usable amount of material that we

with in the lab. So if we're ever looking at a reaction like this the coefficients remember

can work with in the lab so forever looking at a reaction like this the

are going to represent the moles. But it also serves as a bridge most importantly. A bridge

coefficients remember are going to represent the moles but it also serves as a bridge most importantly a bridge

between the mass of an object and the number of particles that are found within that object.

between the mass of an object and the number of particles that are found within that object and so where does the

And so where does the name come from? Avogadro was a Italian chemist. Worked many years ago

name come from abogado was a Italian chemist worked

in the early 1800s. And so he came up with Avogadro's law. Basically as we increase the

many years ago in the early 1800s and so he came up with Avogadro's law basically

volume of a gas, he proposed that we were increasing directly the number of particles

as we increase the volume of a gas he proposed that we were increasing directly the number of particles that

that are found within that. It didn't matter what the gas was. Now he died before they

are found within that didn't matter what the gas was now he died before they

actually came up and quantified this idea of the mole. But we still give him credit

actually came up and quantified this idea of the mole but we still give him

for that early work. And so 1 mole is 6.02 x 10^23. But it's just a quantity. It's like

credit for that early work and so one mole is 6.02 times 10 to the 23rd but

if I have one egg we call that an egg. But if I have 12 eggs we call that a dozen. And

it's just a quantity it's like if I have one egg we call that an egg but if I have 12 eggs we call that a dozen and so

so a mole is just a number. We could have a mole of anything. But it's most important

a mole is just a number we could have a mole of anything but it's most important

when we're dealing with chemicals. To give you an idea of how massive this number is,

when we're dealing with chemicals to give you an idea of how massive this

imagine if I had a mole of marbles. So just regular marbles like this. And I were to start

number is imagine if I had a mole of marble so just regular marbles like this and I

covering the earth. Well I could cover the earth in marbles and that covering of the

would start covering the earth well I could cover the earth and marbles and that

earth would be 3 miles thick. And so there's a huge amount of numbers in Avogadro's number.

covering of the earth would be three miles thick and so there's a huge amount of numbers in Avogadro's number and so

And so when you're dealing with even small amounts of a compound, small amounts of an

when you're dealing with even small amounts of a compound small amounts of

element, you have to understand that you have that many atoms that are found within there.

an element you have to understand that you have that many atoms that are found

Massive amounts. Again it forms a bridge. It forms a bridge between the mass of an object

within they're massive amounts again it forms a bridge it forms a bridge between

and the number of particles that are found there. And so it's really important at that

the mass of an object and the number of particles that are found there and so it's really important at that kind of a

kind of a bridge point. And so let's talk briefly about what an atomic mass unit is.

bridge point and so let's talk briefly about what an atomic mass you and it is

And so let's say we take carbon dioxide for example. It's going to be found in the air.

and so let's say we take carbon dioxide for example it's going to be found in

You breathe it out. It's atomic mass unit is going to be the mass of each of the individual

the air you breathe it out its atomic mass unit is going to be the mass of

atoms. And so we have 1 carbon. So we could look on the periodic table. And the atomic

each of the individual atoms and so we have one carbon so we can look on the periodic table and the atomic mass of

mass of that is 12.01. And then we're going to add 2 oxygens. Each of those are 16 on

that is 12.01 and then we're going to add two oxygens each of those are 16 and

the periodic table. We could find it here. And so its atomic mass unit of carbon dioxide

on the periodic table we could find it here and so it's atomic mass unit of

is going to be 44.01. And so what is an atomic mass unit? It's the mass of one nucleon. So that

carbon dioxide is going to be forty four point zero one and so what is an atomic mass unit it's the the mass of one

could be the mass of a proton or a neutron. Now why is that important? 1 mole of carbon

nucleon so that could be the mass of a proton or a neutron now why is that important one mole of carbon dioxide

dioxide then is going to way 44.01 grams. Let's say we're looking at nitrous oxide. Could

then is going to weigh forty four point zero one grams let's say we're looking

you figure out the atomic mass unit of that? You could pause the video and try to figure

at nitrous oxide could you figure out the atomic mass unit of that you could

this out. Well you'd have to find the nitrogen. You'd have to find the oxygen. And we'd simply

pause the video and try to figure this out well you'd have to find the nitrogen you'd have to find the oxygen and we'd

add that up. So it would be 30.01. But if we had a mole of nitrous oxide that would

simply add that up to be thirty point zero one but if we had a mole of carbon dioxide that'd be 30 point zero one

be 30.01 grams. And so it forms this bridge between the mass of an object and then the

grams and so it forms this bridge between the mass of an object and then

number of particles that are found within that. And this is where sometimes people get

the number of particles that are found within that and this is where sometimes

confused about the mole when they're trying to make these mole conversions. And so let's

people get confused about the mole when they're trying to make these mole conversions and so let's say I had nine

say I had 9.01grams of water. It's almost 10 milliliters of water. And so that would

point zero one grams of water it's about almost 10 milliliters of water and so

be about 2 teaspoonfuls of water. And let's say I wanted to figure out how many molecules

that'd be about two teaspoonfuls of water and let's say I want to figure out

of water are found inside there. Let me show you how the mole can act as a bridge. So we

how many molecules of water are found inside there let me show you how the mole connect as a bridge so we have nine

have 9.01 grams of water. The mole is going to act to convert that into the number of

point zero one grams of water the mole is going to act to convert that into the

particles. So first we use this mole conversion. Remember 1 mole of anything is going to be

number of particles so first we use this mole conversion remember one mole of anything is going to be the

the atomic mass of that in grams of water. So where am I getting the 18.02. I'm adding

atomic mass of that in grams of water so where am I getting the 18 point zero two

the 1 oxygen, 16 plus the 2 hydrogens. And so one mole of water is going to be 18.02

I'm adding the one oxygen 16 plus the two hydrogen's and so one mole of water is going to be 18 point zero two grams

grams. And so what I could do is I can cancel those grams. So now I've converted it to moles

and so what I could do is I could cancel those grams so now I've converted it to

of water. Now we use Avogadro's number. And so I'm going to take 1 mole of water is equal

moles of water now we use Avogadro's number and so I'm going to take one mol

to a number of molecules of water. So 1 mole is equal to Avogadro's number of that. I can

of water is equal to a number of molecules of water so one mole is equal to Avogadro's number of that I can now

now cross off my moles. And now I can solve for the number of molecules of water. And

cross off my moles and now I can solve for the number of molecules of water and

what I get, the math is easy here since I'm taking this, dividing by 18.02, we get 3.01x10^23.

what I get the math is easy here since I'm taking this dividing by eighteen point O two we get three point zero one times ten to the 23rd and so I mean wrap

And so I mean wrap your head around that for just a second. 2 teaspoonfuls of water,

your head around that for just a second two teaspoonfuls of water the number of

the number of water molecules that are found in there would cover the earth in marbles,

water molecules are that are found in there would cover the earth and marbles

if we converted those molecules to marbles 1.5 miles thick. And so now let me give you

if we converted those molecules to marbles one and a half miles thick

one for you. Let's say we have 5.72 grams of glucose, C6H12O6, could you convert that

and so now let me give you one for you let's say we had five point two seven two grams of glucose c6h12o6 could you

to molecules of glucose? And so here are the atomic masses here. I'll put the answer in

convert that to molecules of glucose and so here are the atomic masses here I'll

the video description down below so you can check and make sure you're doing it right.

put the answer in the video description down below so you can check and make sure you're doing it right

Remember that mole serves that bridge. It's also incredibly important in chemical reactions.

remember that mol serves that bridge it's also incredibly important in

This is one of my favorite reactions. This is a thermite reaction. We're getting a combination

chemical reactions is one of my favorite reactions this is a thermite reaction we're getting a combination of iron

of iron oxide with aluminum. And so since it has the oxygen source inside it, this would

oxide with aluminum and so since it has the oxygen source inside it you could

burn under water if you want it to. Okay. So what did we learn in summary? Could you

this would burn under water if you wanted to okay so what did we learn in summary could you pause the video and

pause the video and fill out what's in the blanks? Let me do that for you. So a mole

fill out what's in the blanks let me do that for you

is Avogadro's number. Do you remember what that is? It's going to be 6.02 times 10 to

so a mole is Avogadro's number do you remember what that is it's going to be

the 23rd. It's going to form a bridge between mass and the number of particles. And then

6.02 times 10 to the 23rd it's going to form a bridge between mass and the number of particles and then we use it

we use it to quantify chemical reactions. And so when we're looking at those coefficients

to quantify chemical reactions and so when we're looking at those coefficients

in the front of any kind of chemical reaction, it's going to tell us the number of moles.

in the front of any kind of a chemical reaction it's going to tell us the number of moles and so what should you

And so what should you have learned? Did you learn this? That the mole allows us to connect

have learned did you learn this that the mole allows us to connect particles

particles, moles, mass, volumes all together. Both qualitatively in the form of for example

moles mass volumes all together both qualitatively

a chemical reaction where we're writing that out. And quantitatively. Actually calculating

in the form of for example a chemical reaction we're writing that out and quantitatively actually calculating the

the number of particles in material. So that's the mole. It's just a number. And I hope that

number of particles in material so that's the mole it's just a number and I

was helpful.

hope that was helpful