Moles - LeFonch

Moles Are a Basic Quantity

Moles are a unit of basic quantity, used to represent the amount of substance.
One mole represents a very large number of particles, and is often used in conjunction with other terms, for example molar mass, which is the amount of grams one mole of an atom is.
Moles are written as mol, and they are represented by a lowercase n.
A mole is a very large quantity, and is used for measuring large quantities of very small entities such as atoms, molecules or other particles.

A pair is 2 units.
A dozen is 12 units.
A baker's dozen is 13 units.
The amount of chess pieces in a set is 32.
The current amount of Nazis in the current Finnish parliament is 46.
A gross is 144 units.
The Finnish parliament has a total of 200 members.
A ream is 500 units.
The amount of stars in the visible universe is a whopping 70 000 000 000 000 000 000 000.
For comparison, the amount of units in a mole is 602 214 076 000 000 000 000 000.

Moles of different atoms contain the same amount of particles, but can have different volumes and masses.
This is due to the different sizes of atoms.
A mole of any substance contains 6,022 x 10^23 particles.
The unit 6,022 x 10^23particles/mol is called Avogadro's constant, as it was first thought of by Italian scientist Amedeo Avogadro.
Avogadro's constant is designated as N–A.
N is the number of particles in a mole, being 6,022 x 10^23.

Molar mass is represented as M and it is the mass of a quantity of substance that is equivalent to one mole.
For example one mole of Carbon is 12.011 grams.
The unit of molar mass is g/mol (amount of grams of the substance/one mole, or grams per mol).
The molar mass of a substance depends on the mass of atoms and number of ions.
The molar mass can be found on a periodic table under the symbol of an element.
Molar mass and atomic mass are the same, except molar mass is in grams and atomic mass is in atomic mass units, or amu.
For example oxygen has an atomic mass of 16 amu and a molar mass of 16g/mol.
Molar mass includes the average of isotopes (however isotopes are uncommon enough to not have a significant impact on the molar mass).
The molar mass of molecules can be found by adding together the different molar masses of the particles in the elements.
For example the molar mass of oxygen is 16,00g/mol.
The molar mass of hydrogen is 1.008g/mol
The molar mass of H2O is:
(1.008 x 2 + 16.00)g/mol = 18.016g/mol

The amount of moles is the same as grams divided by molar mass.
n=m/M
n is the amount of moles, m stands for mass which is grams in this case and lastly M stands for molar mass.
Thus if we move M from one side to the other we get: m = nM.
This means mass can be calculated by multiplying the amount of moles with molar mass.
For example you need 0.640 moles of iron for your experimental work. How much should it be weighed?
The mass of iron is:
m(Fe) = n(Fe) x M(Fe) = 0.640mol x 55.85g/mol = 35.744g ≈ 35.7g
Answer: 35.7g of iron needs to be weighed.