easy but not understood question of chemistry?

Question

- What are moles????

plz xplain with the help of some example,cz i've read like tonz of definationz about it and still sometimes seem to be confused.

thnx a bajillion!

Answer 1

A mole of substance is a relative measurement of the amount of substance. It is used to simplify chemical reaction calculations, which otherwise would involved very large numbers. The key thing is:

1 mole of any element/molecule = 6.02 x 10^23 atoms/molecules

For example:

Burning of methane:

CH4 + 2O2 --> CO2 + 2H2O

1 mole of CH4 is present, to react with 2 moles of O2 to form 1 mole of CO2 and 2 moles of H2O. (rather than sticking in the huge number from above to calculate reaction masses using n = m/Mr)

To calculate the number of moles (n) take the mass of the element/compound in grams (m) and divide it by it's molecular mass (sum of all the elements in the element/molecule from the periodic table)

Hence the units for a mole are g/mol.

Answer 2

Mole is a counting unit used by the chemist. for example 1 dozon of oranges mean 12 oranges.
So mole is a counting unit which contains 6.023*10^23 entities.
For example----
1 mol of H- atom = 6.0232*10^23 atoms.

1 mol of H molecule= 6.023*10^23 molecules.
This number is used because Carbon(C^12) is taken as a reference.So 1 mol 0f a Carbon weighs = 12 g and contains 6.023*10^23 atoms of carbon.
Moreover it is very difficult to measure the weights of atom and molecules but counting is easy then weighing.

1 mol of a substance is equal to its molecular mass when expressed in grams.
for exzmple:-
1 mole of H2O = 1*2 + 16 = 18 g/mol
HOPES u GOT iT.

Answer 3

They are arbitrary proportional units used to create chemical equivalents.
They could be gram mols (most common)
pound mols
ton mols
or ANY other mass unit

The point is that one mole of Na combines with one half mole of Cl2 even though the mole of Sodium weighs 23 units and the mole of Cl2 weighs 71 units. Also gram mols theoretically correspond to a certain number of particles (Avogadro's number = 6.02 x 10^23).


pound mole (lbmol)
a unit of amount of substance. One pound mole of a chemical compound is the same number of pounds as the molecular weight of a molecule of that compound measured in atomic mass units. Thus the pound mole is equal to exactly 453.592 37 moles.

"However, if in the future the kilogram is redefined in terms of a specific number of carbon-12 atoms (see below), then the value of Avogadro's number will be defined rather than measured, and the mole will cease to be a unit of physical significance."

Answer 4

re the answer above, i've never heard of anything other than gram moles, i think maybe that just confuses the issue. a mole is avogadro's number of particles. they can be any sort of particles, whether it's electrons, atoms or molecules.

the reason that this is useful is that chemical reactions occur between particles in fixed, whole number proportions (this is the concept of stoichiometry). so if you have a reaction with known stoichiometry, and you can figure out how many particles of one type are reacting (or equivalently, what number of moles) you can figure out how many moles of all other particles must be present as either reactants or products.

Answer 5

mole is a quantity as well as it is a number.atomic mass,molecular mass,formula mass expressed in grams is called 1mole e.g,32g of O2 is 1mole , 58.5g of NaCl is 1mole mole=mass in gram/molecular weight mole is also a number.1 mole O2 has 6.022(10)/\23 molecules.1mole of any substance has Avogadro's no. of molecules. mole=no. of molecules/Avogadro's no.