Mole definition

[zbentinel]

After browsing a few pages looking for a definition of the word Mole I cannot find one which is similar to the last definition I found.

 

Could someone tell me what A Mole is.

 

Also here is a sentence in my chemistry book that uses the word and I don't understand what any of it means.

 

 

"The first Ionisation Energy of an element is the energy required to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions."

 

Also, what's a gaseous atom?

[swansont]

A mole is Avogadro's number of a substance (6.02 x 10^23)

 

A gaseous atom is one that is normally a gas under the stated conditions (usually STP), e.g. Helium, Argon for monoatomic examples, or Hydrogen, Oxygen, Nitrogen, Carbon Dioxide for molecules.

 

You ionize an atom by removing a single electron, and repeat until you've done that for 1 mole. The energy it takes to do that is the first ionization potential.

[CaptainPanic]

A mole is a word that's similar to a dozen or a gross. A mole is a number.

 

dozen = 12

gross = a dozen dozen = 12*12 = 144

mole = 6.022*10^23

 

So, if you have 3.5 gross eggs, you have 3.5*144 = 504 eggs.

If you have 3.5 mole nitrogen molecules (N2), then you have 3.5*6.022*10^23 = 2.1077*10^24 nitrogen molecules.

But because that number is so ridiculously large, and we never count individual molecules anyway, we prefer to say "3.5 mole nitrogen molecules".

 

Sadly, all textbooks I've come across make a lot of fuss about why the number "mole" is what it is (namely 6.022*10^23) but don't mention that it's just similar to a dozen. In practice, you don't need to know any more than that it's a number.

[jian]

A mole of particles refers to the cluster of particles with the number of particle number is the Avogadro constant [math]N_{A}[/math].

 

Gaseous atoms means that the substance is in gaseous phase, not in other phases like solid,liqiud or aqueous. In the definition of first ionization energy, the restriction of gaseous atoms is necessary becuase the energy to ionize 1 mole of subtance is different in different pahses.

[zbentinel]

Ok then I think im starting to understand this, but is a mole a number of atoms, or a number of particles (protons, neutrons and electrons) within an atom?

 

and does Na(g) mean gaseous sodium? if so, how does one turn Sodium into a gas?

[hermanntrude]

A mole can be of anything. It could be a number of atoms or it could be a number of any other particle or even a number of hippopotamuses (although the earth would probably be coated miles deep in hippos if there were a mole of them).

 

Anything can be made into a gas if you get them hot enough or put them in the right pressure environment. Many street lights contain gaseous sodium. You can tell because of the orange colour.

[zbentinel]

Great, thanks for that, so now I just have to look at what follows the word mole, if its of gaseous atoms I know that it mean exactly that, excellent. Thank you all for your help!

[CaptainPanic]

A mole can be of anything. It could be a number of atoms or it could be a number of any other particle or even a number of hippopotamuses (although the earth would probably be coated miles deep in hippos if there were a mole of them).

 

An average hippo is 1500 kg. Hippo's sort of float, therefore their density is similar to water. Therefore a hippo is 1.5 m3 on average.

 

1 mole of hippo's is therefore 1.5 * 6.022*10^23 = 9.033*10^23 m3 in volume.

The volume of the earth is 4/3*pi*r^3 = 4/3*pi*(6.378*10^6)^3 = 1.086*10^21 m3 (the volume of the hippos far exceeds our tiny earth).

 

We then must add these two volumes, calculate the total radius, and subtract the earth's radius:

 

total volume = 9.044*10^23

total radius = 60*10^6 m

radius earth = 6.378*10^6

 

So the layer of hippos is about 54*10^6 m, or 54000 km thick.

 

So, not miles deep... more like the Earth becomes the size of Jupiter

 

Sorry for adding a completely pointless post - I just enjoy silly calculations such as these. Time to get serious again.

[hermanntrude]

An average hippo is 1500 kg. Hippo's sort of float, therefore their density is similar to water. Therefore a hippo is 1.5 m3 on average.

 

1 mole of hippo's is therefore 1.5 * 6.022*10^23 = 9.033*10^23 m3 in volume.

The volume of the earth is 4/3*pi*r^3 = 4/3*pi*(6.378*10^6)^3 = 1.086*10^21 m3 (the volume of the hippos far exceeds our tiny earth).

 

We then must add these two volumes, calculate the total radius, and subtract the earth's radius:

 

total volume = 9.044*10^23

total radius = 60*10^6 m

radius earth = 6.378*10^6

 

So the layer of hippos is about 54*10^6 m, or 54000 km thick.

 

So, not miles deep... more like the Earth becomes the size of Jupiter

 

Sorry for adding a completely pointless post - I just enjoy silly calculations such as these. Time to get serious again.

 

nice one. I was going to do the calculation too but decided against it. miles deep is still techinically correct... and i imagine the layer would be less thick as the hippos at the bottom (and the earth itself) would be crushed smaller by the weight of the hippos on top.

[John Cuthber]

There are, according to wiki only about 15000 hippos left.

Would chemists be more likely to get involved in their conservation if it were widely explained that the whole earth only holds about an attomole of hippos?

What about the yoctomole levels of Pere David's deer etc?

[J.C.MacSwell]

An average hippo is 1500 kg. Hippo's sort of float, therefore their density is similar to water. Therefore a hippo is 1.5 m3 on average.

 

1 mole of hippo's is therefore 1.5 * 6.022*10^23 = 9.033*10^23 m3 in volume.

The volume of the earth is 4/3*pi*r^3 = 4/3*pi*(6.378*10^6)^3 = 1.086*10^21 m3 (the volume of the hippos far exceeds our tiny earth).

 

We then must add these two volumes, calculate the total radius, and subtract the earth's radius:

 

total volume = 9.044*10^23

total radius = 60*10^6 m

radius earth = 6.378*10^6

 

So the layer of hippos is about 54*10^6 m, or 54000 km thick.

 

So, not miles deep... more like the Earth becomes the size of Jupiter

 

Sorry for adding a completely pointless post - I just enjoy silly calculations such as these. Time to get serious again.

 

How about a mole of moles?The furry kind that can't see very well. That must be closer to the moon's size.

[Kyrisch]

An average hippo is 1500 kg. Hippo's sort of float, therefore their density is similar to water. Therefore a hippo is 1.5 m3 on average.

 

1 mole of hippo's is therefore 1.5 * 6.022*10^23 = 9.033*10^23 m3 in volume.

The volume of the earth is 4/3*pi*r^3 = 4/3*pi*(6.378*10^6)^3 = 1.086*10^21 m3 (the volume of the hippos far exceeds our tiny earth).

 

We then must add these two volumes, calculate the total radius, and subtract the earth's radius:

 

total volume = 9.044*10^23

total radius = 60*10^6 m

radius earth = 6.378*10^6

 

So the layer of hippos is about 54*10^6 m, or 54000 km thick.

 

So, not miles deep... more like the Earth becomes the size of Jupiter

 

Sorry for adding a completely pointless post - I just enjoy silly calculations such as these. Time to get serious again.

 

It would appear that you are assuming 100% packing efficiency. That would make for some very uncomfortable hippos...

[J.C.MacSwell]

It would appear that you are assuming 100% packing efficiency. That would make for some very uncomfortable hippos...

 

101%!

 

I think we are assuming the majority are liquid hippos.

[BlondeEngineer]

Since molecules are sooo damn small, a quantifiable number was created ->

6.022*0^23...

 

This was not arbitrary -> it seems most gases behave exactly the same at STP

(Standard Temperature and Pressure) by being contained in 22.4Liters of space...

 

The space itself is not arbitrary, gas was filled in a container that's volume, temperature and pressure was controllable and could be varied... Hence how you can get the special

PV=nRT equation. R being a constant specific to the gas at certain temperature and pressure (there are tables in the back of your chem book for STP BUT you need a Thermodynamics book to get other temp/press values.)

 

This mole number came about because of the above special gas behavior, but as always scientists decided to keep everything the same so they made mole number useful for ALL elements hence the mole mass number on the bottom of each element in the periodic table...

 

now: IONS -> Believe it or not, you are an energy field... What we think of as solid is actually the magnetic field created by the electrons travelling around the nucleus... We are in actuality 99.99999999...% free space!!! Now most atoms are in a normal happy situation where each positive proton within the nucleus has a happy negative friend called the electron wizzing around the outside... When the pair is broken either by radiation where a proton is released, or by having an electron escape OR having another electron hitchhike, the atom has imabalance in electrical polarity... If there are more protons than electrons, you get that much more positive energy sending out a want ad looking for negative partnership. If there are more electrons than protons, you get the opposite effect, the atom is looking for positive partnership.... Either way, these atoms looking for partners are called IONS... The positive ones are CATIONS and the negative ones are called ANIONS. Voltage in a battery is determined by how many Cations and Anions are wanting each other within the battery. When you rub your wool socks against your polyester carpet, the wool steals electrons from the carpet creating a "charge". Zapping a friend gives the electrons a chance to run back down to the ground whence they came. Very basic and a bit simplistic but I hope you get the picture...

 

Here's an ionic chemistry equation:

 

H+ + OH- = H2O

 

Ionization has a lot to do with acidic and basic reactions...

 

H+ acidic

 

OH- basic

 

Does that mean water is a SALT??? ROFLMAO

[Sisyphus]

Since molecules are sooo damn small, a quantifiable number was created ->

6.022*0^23...

 

This was not arbitrary -> it seems most gases behave exactly the same at STP

(Standard Temperature and Pressure) by being contained in 22.4Liters of space...

 

The space itself is not arbitrary, gas was filled in a container that's volume, temperature and pressure was controllable and could be varied... Hence how you can get the special

PV=nRT equation. R being a constant specific to the gas at certain temperature and pressure (there are tables in the back of your chem book for STP BUT you need a Thermodynamics book to get other temp/press values.)

 

This mole number came about because of the above special gas behavior, but as always scientists decided to keep everything the same so they made mole number useful for ALL elements hence the mole mass number on the bottom of each element in the periodic table...

 

No, no, no! I can't believe nobody has mentioned this yet, but where moles come from is that a mole of atoms or molecules of total atomic weight N will weigh N grams. That's it. A mole of carbon 12 weighs exactly 12 grams, everything else is approximate. Note, that's where the number comes from, but others are correct in saying that it is "just a number."