h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: The Mole (Chemistry) - A2998876
Author: radioactiveBIGAL1 - on a different planet. Keeper of Mnemonics and of the Renowned Glowing Pickle - U723247

P>This is a collaborative effort between myself and Hell. What do people think?

Well I'm not a chemist and I understood it - thought I have had a refresher helping a teenager daughter with her A level chemistry recently.

So I've always wondered ' "This number was given the name, 'mole'." WHY ?

Obsessed with Su Townsend characters ?

well done BigAl and Hell keep the torch burning for Chemistry even if the UK Universities don't.

As for why Mole...... substitute the word MOLEcule for atom in the definition. Well that's always been my interpretation, I'm ready to be corrected.

interesting trivia...

Mole Day is an unofficial holiday celebrated among chemists on October 23, between 6:02 AM and 6:02 PM, making the date 6:02 10/23 in the American way of writing out dates. The time and date are derived from Avogadro's number.

There's also....

Pi Day, Square root day, Newtonmas, Darwin_Day

details on: http://en.wikipedia.org/wiki/Mole_Day

Brilliant: I couldn't have explained this concept better myself. I can see why you're a chemistry teacher.

You might want to add an explanation about why 12g of C12 *doesn't* have the same number of atoms as 1g of H1. e equal em see squared and binding energy and all that. Also, put the answer to the grains of sand problem into a footnote. Don't tease!

Will do.

I like it! I'll try to remember this when the appropriate day comes up in the teaching calender.

Hmmm... Hi. I have a heretic suggestion: It takes a long while until you explain what a mole actually is, you first introduce the atomic mass unit and then devcelop the idea to reach the mole. All done very nicely, indeed.

Maybe, however, you could introduce a small summary in the beginning for those that only want a quick answer

Second minor nit (as you know...): The recation H2 + O -> H2O would be better 2H + O -> H2O, starting from the atoms, perhaps.

Good job!

HELL

Good article - very well written. I have just taken a brief look through it and I have just one slightly critical comment: would it be possible to provide the English names of the elements in your tables? Ie. as well as U, say "Uranium" etc?



Woodpigeon

I've incorporated your suggestion Hell. I will incorporate yours too, FM but I'll leave it until I'm feeling in the mood (it's a bit late at present).

I'm not sure about your suggestion, WP - about writing iun the full names of the elements, as I've hyperlinked to the Periodic Table Entry. However, if others reinforce your suggestion, I'll certainly do it.

at the beginning you say:

"it is a quantity (of anything!) that is equivalent to the number of atoms present in carbon-12"

that doesn't really make sense, say the number of atoms present in 12g(or 0.012kg) of carbon-12.

"This figure is called the Avogadro Constant, NA (sometimes, the Loschmidt Number,L) after the Austrian chemist who first estimated its value."

According to The Short History of Nearly Everything by Bill Bryson, Avogadro was Italian, or are you referring to the Loschmidt guy? If so, use of brackets is confusing.

If you need any mathmatical symbol codes or anything check out this page
http://www.bbc.co.uk/dna/h2g2/A1098876

Got a bit clumsy towards the end, maybe a few grammatical and punctuation errors, nothing major, just give it a check over.

"10^-23" is that right? should the minus be there?

Otherwise, good work, particulary liked the start.

SuperSam

P.S. Incidentally, I read today that scientists want a new standard for the kilogram because they say the template is to inaccurate for modern physics, because it changes weight(or mass, whatever) when its taken out to be cleaned. How pedantic do they need to be?!(intterrobang)

<"it is a quantity (of anything!) that is equivalent to the number of atoms present in carbon-12"

that doesn't really make sense, say the number of atoms present in 12g(or 0.012kg) of carbon-12>.

Well, what I was trying to say isd that a mole of carbon-12 contains 6.022 x 10-23 atoms, and one can have this quantity of anything at all, atoms, molecules, electrons...


closing bracket it wrong place.

<"it is a quantity (of anything!) that is equivalent to the number of atoms present in carbon-12">

I see what you mean - I forgot to include the quantity of carbon-12. Fixed now.

6.022 10E+23 (!!! + !!! not !!! - !!!)

HELL

Hell. I did notice this, and I think it's correct in the Entry. I'll check.(For some reason '10 to the minus... trips off the tongue somewhat too readily!)

s to check.

Yep, checked that. Can't see the same error reproduced anywhere in the text.

OK, I meant your post anyways...

HELL

Well, there was a rogue '10 to the minus...' in the Entry at one stage

When I was in first year of college some of the class had great difficulty understanding the mole. So the lecturer would ask how many moles of wheels there were in one mole of bicycles! That way, with a visulaizable example (I'm a neologist), they could grasp it more readily.

The other thing is to compare the mole to the dozen. It works exactly the same way, it's just bigger.

By the way, 6.022*10^23 is Avogadro's number.
Avogadro's constant, NA, is 6.022*10^23 mol-1.
(This same lecturer is a pedant about units. It's catching!)

TRiG.