Before I start explaining what a 'mole' is, first understand the concept of what a mole is. Think about an analogy to 'dozen'.
Whenever we talk about 'dozen', we are talking about the number 12., i.e., 1 dozen pencil/pens etc. = 12 pencils/pens.
Similarly, whenever the term 'mole' is taken, we are talking about the number which should come to our mind, which is 6.022*(10^23) and which is called Avagadro's Number.
Thus, 1 mole of anything (may it be atoms, molecules, ions etc.) means 6.022*(10^23) of that thing is present.
Hence, a mole is nothing but a large number used to represent the quantity of something present in that range.
Now, there are certain formulas to calculate the number of mole of a substance:
1) moles of a substance = number of molecules/atoms/ions etc. of the substance/6.022*(10^23) (Avagadro's Number)
2) moles of a substance = mass of the substance/molar mass of the substance
NOTE: Molar mass of the substance is the mass of one mole of that substance.
A mole is simply put, an amount of a substance. It is kind of confusing because it implies that one mole of oxygen is the same as one mole of hydrogen, which is actually true.
Each mole of a substance is equal to 6.022X 10^ 23 atoms or molecules.
Moles is a unit of measurement which can be calculated by dividing mass in grams by the molar mass
This is used to measure the quantity, numerical value of a chemical substance for an element or a compound.
Moles is a unit which is used to measure quantity of a chemical substance like an element or a compound. 1 mole of element or compound is always equal to the molar mass of that substance. Ex. 1 mol of Sulfur = 32g of Sulfur , 1mol of water = 18g of water . Moles (N) = Mass (g) / Molar Mass (mm)
In the above answer I intended to use 6.02.
The above answer is incorrect. Rather than 6.2 x 1023, it should read 6.2 x 10 to the 23rd power, the number of beer cans it would take to cover the entire earth to a depth of 9 miles (big number).