# the mole (1 Viewer)

#### Nichola

##### New Member
Would someone please explain the mole concept to me. This is coming from an extremely floundering fish in the sea of preliminary chemistry!

#### Dario

##### Member
I sorta remember the name from a year 10 science course but can't tell you what it exactly is. I'll have a look in my year 10 Science exercise book and post an explanation soon, as I am at school now. By the way, most people find Chemistry hard and a lot of people I know have dropped it in year 12. If you are thinking of Extension 2 Maths, you would have 14 units, so if you want 12, drop something that you don't like or you aren't doing well in (like Chemistry).

Good luck Nichola!
Knowing you, you'll do extremely well as usual !
Keep up the good work !
persistence .... persistence .... persistence .... persistence

#### Dario

##### Member
Well, this probably won't help much, but this is what I found :

The mole is 6.02E23 units

1 mole of ^12C has a mass of 12 g exactly
Therefore, 1 mole of oxygen atom is 16g and one mole of the Oxygen molecule O 2 is 32 g

"M" is the letter for molar mass Units of molar mass are g/mol

i.e. MO2 = 32 g/mol

+++

The number of moles is given by n = mass/molar mass

i.e. For 64g of O2
n = mass/molar mass
n = 64g/32gmol^-1
n = 2 mol

#### Nichola

##### New Member
Thank you, Dario, you're a sweetie as always, encouraging me!

Your explanation helped me, but I think its more the calculations I have trouble with. Next time I have a problem, I'll post it for you to work out hehe. Be thankful you're not doing chemistry!!
Luv, Nic

#### bertyboi

##### New Member
The mole, is the amount of a substance in g relative to the C atom
Eg. N is 14.00 grams i think, therefore 14 grams of nitrogen would be relative to a C atom.
1 mole of a substance contains 6.023 X 10e-23 atoms/molecules for ALL substances eg. One mole of H20 and one mole of NO2 would have the same amount of molecules present
A mole is an easy measure of relating each Element to each other - thats the easiest i can explain..

#### Mac.D

##### New Member
mole = mass of the element divided by the molecular mass (mass of the element, get that from the periodic table)

the mole is just quantity, like kilograms and litres.

#### Lord Ac

##### Trust me *wink*
My teacher explains the mole as like saying "a loaf of bread'; its short for saying the whole thing, ie: "12 pieces of bread". A mole = heaps x heaps x heaps of particles ... ie. the amount of C-12 in something or other ...

Ac

#### Mac.D

##### New Member
yeah what nichola said, its like when you measure sand, you dont measure it by each grain, you measure it by the kilo.

to give you some perspective, i think it is oxygen, one mole of oxygen at normal pressure and temperature, is a 30cm cube.

#### Weisy

##### the evenstar
A mole is a measure of number of particles of anything. This number is 6.02x10^23, I think. So regardless of relative atomic mass, a mole of carbon atoms has exactly the same number of particles in it than a mole of uranium atoms, despite the obvious differences in their weight.

Hence, there must exist a 'mole ratio' by which the number of particles of any substance can be compared to the number of particles for another substance, regardless of particle mass.

This mole ratio is given by the mass/molar mass (mass in g, molar mass in g/mol, as the more massive a particle is, the less number of particles present in a given mass.

Sometimes people like to define the mole as "the number of carbon-12 atoms in 12g of that substance". This is because in this situation, mol=12/12 = 1.