Can someone please explain a "mole" to me?

Question

I mean, I know the definition: a mole is a quantity -- like a dozen -- and it is equal to the number of carbon atoms there are in 12g of pure C-12. I definitely understand that. What I DON'T understand is why that is significant to anything else.... Why must every chemical equation be in terms of "moles" of a substance? I don't get why the mole is so important.

Can someone please explain this to me? Thanks so much!! I'll pick a best answer TODAY!!!!!!!!!!!

Answer 1

Mole is the English version of the German word "Mol" which is short for

Molekulargewicht, the "molecular weight."

Answer 2

Good question.

The mole is a measure of AMOUNT of stuff. It is a kind of common currency for comparing different materials.

Say you want to know what mass of oxygen you would get from burning 6.0 g carbon.  The balanced equation

C + O2 --> CO2

tells you that each mole of carbon will give you just 1 mol CO2.  Divide 6g by 12 g/mol to find the number of moles of C (0.50), and multiply that number of moles by the molar mass of carbon dioxide (44.0) to get your answer (22.0 g).

Also, when you study the behaviour of gases, you will find out that at any temperature and pressure, the volume is directly proportional to the number of moles.

We use the mole because historically chemists used grams to express mass, and moles take you from atomic mass units to grams. There is exactly 1 mol of atomic mass units in 1 g.

Hope this helps.

Answer 3

Moles are used as opposed to grams because it is more accurate, and with the number of moles of reactants you can find the exact number of moles of the product. To simplify, you can know that you have 10 hydrogen atoms and 20 oxygen atoms and that they will make 10 water molecules. Its really just about accuracy.

Answer 4

A mole  the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of carbon-12 (i.e., 6.023 X 1023). In simple English moles are measurements for chemicals the same way we have measurement symbols for length, mass, etc. A mole this time around measures the atomic weight of a molecule of the chemical in grams. Its very simple. dont mind the huge definitions in textbooks. Read on!

Answer 5

Actually is Avogadro's number or ~6.022 x 10^23.

When a chemical reaction occurs, a specific number of atoms of one element reacts with a specific number of atoms of another. 2mol of Hydrogen reacts with 1mol of Oxygen to create 1 mol of H2O.  If lbs or kilograms were used, you would have to convert to the number of moles to determine the atomic proportions. 1 mol of a substance is exactly equal to the molecular weight of the substance in grams.

When you're dealing with ideal gases, regardless of the molecular weight, 1 mol of the gas molecules at standard temperature and pressure occupy 22.4 liters of volume.

The definition you're familiar with as the number of atoms of 12g of pure C-12 is really just a convenient constant to base many others on.  Before 1960 it was based on O-16.  In 1960 the SI measurement system defined it as it is today and all of chemistry and physics had to adjust their constants to be related to the new number.  Now it is standard and everyone in the world can speak the same language with Chemistry and Physics.

Note:  I'm a chemical engineer so you can trust me on this one.  Wikipedia has a good article on it also.

Answer 6

Imagine the reaction between two atoms...we'll pick Hydrogen and Chlorine.

Now, these atoms combine to form HCl, or hydrocloric acid.

Now, let's assume that you want to make some HCl.  We would need one atom of H for every atom of Cl, right?  Well, when we weigh the hydrogen, it's much lighter than the chlorine.  So we need some other way to make sure that the amount of atoms in each sample is equal.

We do this using the molar weight.  If we were to add 1 gram of hydrogen to 1 gram of chlorine, there would be alot more hydrogen than chlorine.  However, if we add one mole of hydrogen to one mole of chlorine, we would have a balanced reaction.   That's what moles do for us...they allow us to mix equal amounts of atoms or compounds so that the reactions will have enough 'ingrediants'.

Answer 7

A mole is 6.022*10^23 or Avogadro's number.  

When you have this number of carbon atoms, then you have 12 grams of carbon.  

Look for the atomic mass of an element on the periodic table.  One mole of atoms of an element will weigh the number of grams equal to the atomic mass.  For example, the atomic mass of iodine is 127.  One mole of iodine atoms will weigh 127 grams.  

A mole is a huge number.  A mole of marshmallows will bury the whole Earth 60 miles (100 km) deep.  

Answer 8

Chemical equations need to be based on moles (or at least some sort of quantity-based measurement), because reactions take place in ratios of amounts of things. 1 O2 molecule reacts with 1 sugar molecule. Those two things weigh completely different things, so weight won't work, we need quantity. A mole is a useful quantity to pick because it makes calculations easy with molecules.

Answer 9

ummm i'm not really sure but for equations its really important b/c grams dont give u the percentage of an element in an equation for example: 16 grams Oxygen and 2 grams of Hydrogen....if u were to look at only the grams, there are 8 times as much Oxygen as there is Hydrogen...but in moles it would be 1 moles Oxygen and 2 moles Hydrogen...therefore u need 2 hydrogens ffor every oxygen.....ummm if i confused u, sorry!

Answer 10

i only know of two diffrent kinds of moles

mole>a brown circular bump on the body

mole>an animal that burrows under ground

i hope this helped and im sure you "mole" is a type too (i think)

Answer 11

A mole is so generic that it works well. You can have a mole of atoms or a mole of molecules...even a mole of doughnuts it doesn't matter.

It's easy to convert between moles and the metric system and it works well with the metric system (e.g. a common unit for concentration is the molarity (moles/liters).