Concept of Mole - Part 1 | Atoms and Molecules | Don't Memorise

When we go to a supermarket, we always buy things

using standard values.

In other words,

we always take one kilogram of rice

or 200 millilitres of fruit juice.

Fruits are sometimes counted using the unit dozen.

One dozen means 12 of something.

These are terms used in everyday life.

But what if I want to measure something in terms

of the number of tiny particles present in it?

Let me explain this in detail.

Looking at this pure gold,

can you tell me

how many gold atoms are present in this?

Or wait... looking at this glass of water,

can you tell me how many

water molecules are present in it?

You will probably say that it's practically impossible to

calculate the number of atoms

or molecules in these examples.

But astonishingly,

chemistry has an answer to this as well.

That brings us to the concept of mole.

What does it mean? It's very easy.

One mole of anything has six point zero two two times

10 raised to 23 atoms or molecules

or particles present inside it.

Isn't this number huge?

If I have to write down the zeros,

this is how big the number will look.

One mole of anything has these many particles.

Now let's say we take a substance

which has three times a number of particles here.

Then we say that this is 3 moles of this substance.

And what if we have a substance which has

8 times the number of particles here?

That's correct. It will be 8 moles of that substance.

That's the basic concept of a mole of any substance.

Let's see if you've understood the concept well.

Now here's one mole of this pure gold.

How many atoms does it have?

Yes as it's one mole,

it will have 6.02 times 10 raised to 23 atoms in it.

Similarly, one mole of pure water will have 6.022 times

10 raised to 23 water molecules inside it.

So is this how we define one mole?

6.022 times 10 raised to 23

atoms or molecules or particles?

Well, that's the simplest way to understand it.

That means if we take for example

a bag containing 6.022 times 10 raised to 23 hydrogen atoms,

then can we say it's one mole of hydrogen?

Yes, that's right.

Similarly, 6.022 times 10 raised to

23 molecules of any compound

like copper sulfate is one mole of copper sulfate.

Simple, isn't it?


We have just understood the concept of mole

in simple words.

But we are yet to take a look

at the scientific definition of one mole.

And what's this number we refer to?

Does it have a special name?

Watch our next video to know more.