Tuesday, October 23, 2012

Happy Mole Day!

As I post this, the time is 06:02 on October 23rd. For some of you, that may mean something. For the rest of you, I'll explain.

The importance of the day begins with the scientist Amedeo Avagadro, born on August 9th, 1776. If you've taken high school chemistry you'll remember (hopefully) the term "Avagadro's number". It is equal to 602,000,000,000,000,000,000,000 or, using scientific notation, 6.02x1023. It's a unit of measurement more commonly known as The Mole. Nerdy chemists like myself like to make a big deal out of "Mole Day"  - 06:02 10/23. This week is even National Chemistry week in the US.

But what exactly is a mole?

The most common comparison is that a mole is like a dozen. You know that there are 12 eggs in one dozen eggs. You know that there are 12 cars in one dozen cars. In fact, it's silly for me to continue the example - there are 12 of anything in one dozen of that thing. The term "mole" is the same, except instead of 12 in a dozen there are 602,000,000,000,000,000,000,000 in one mole. Remember that chemists study atoms and molecules, which are very small. While one mole may seem like a huge number (and it is) there are a huge number of molecules surrounding us - 18 mL of water contains roughly one mole of water molecules.

But maybe that doesn't shock you. You have no real concept of the size of an atom, so let's look at some examples of bigger things:

  • If I were to stack one mole of quarters on top of each other it would reach to the moon and back 1,370,000,000,000 times. 
  • Speaking of money, the US deficit is a hot button issue. However, if I had a mole of dollars I would have enough to pay for it myself 37 billion times. 
  • One mole of Oreos has enough calories to fill the recommended daily intake for the entire world population - for 10 billion years.
  • If you were to eat all those Oreos at once, you'd have to run around the earth 99,000,000,000,000,000 times to burn off the calories of your midnight snack.1 
I hope you can see by now that a mole is a really, really big number. Now let's go back to the water example. Like I said, there are a mole of water molecules in just 18 mL of water. That may begin to show you how incredibly small molecules are. If you're like me though, it still seems like something I can't really wrap my head around. Either way, have a very happy mole day!
Notes
[1] Perhaps I could be accused of writing this late while contemplating a plate of cookies. I can neither confirm nor deny...

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