Mole (unit)
The mole is the unit of measurement in the International System of Units (SI) for amount of substance. It is defined as the amount of a chemical substance that contains as many elementary entities, e.g., atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of pure carbon-12 (12C), the isotope of carbon with relative atomic mass 12 by definition. This number is expressed by the Avogadro constant, which has a value of 6.02214129(27)×1023 mol-1. The mole is one of the base units of the SI, and has the unit symbol mol.
The mole is widely used in chemistry as a convenient way to express amounts of reactants and products of chemical reactions. For example, the chemical equation 2 H2 + O2 → 2 H2O implies that 2 mol of dihydrogen (H2) and 1 mol of dioxygen (O2) react to form 2 mol of water (H2O). The mole may also be used to express the number of atoms, ions, or other elementary entities in a given sample of any substance. The concentration of a solution is commonly expressed by its molarity, defined as the number of moles of the dissolved substance per litre of solution.
Podcasts:
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by Irving Berlin
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by MELEE
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by Tata Young
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by Marlene Kuntz
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by Bebe
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by Maleh
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by Mylah
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by Bhupen Hazarika
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by Rafaqat Ali Khan
Molly O! Oh, Molly!
by: Irving Berlin[1st verse:]
Mike O'Toole, on a stool
Sat one Sunday morning fair
Molly O, pure as snow
Happened to be passing there
She smiled and said, 'I see you're all alone'
Listen to some blarney Michael brought from home
'Maiden sweet, half my seat
You can have, sweet Molly O
Faith I'm glad that your dad
Wed your mother years ago
They never thought their girl and Mike O'Toole
Would sit and talk upon the same old stool
[Refrain:]
Molly O, oh, Molly, I adore you
And I've got the spot, a regular house and lot
There's a great big future, dear, before you
I hate to be talking about myself
But when it comes to being father
I'm as gentle as could be
You don't say no, so now is me time to go
Consider yourself engaged to me
Good morning, Molly
[2nd verse:]
Molly sighed, then she cried
'Don't you think you'd rather stay?'
Michael winked, said, 'I think
This will be a lovely day'
They sat for hours on the same old stool
Spooning like the teacher never taught at school
Michael read from his head
Seven chapters of a book
Ev'ry line meant a fine
Irish kiss that Michael took
At three A.M. beneath the smiling moon
The milkman heard him sing the same old tune