**** Avogadro's Number

[OverVolt]

If you want to make your teachers laugh, ask them why a banana doesn't explode in your mouth when you eat it, because of the potassium.

 

[bigrash]

I love the taste of avocado.

 

[manimal]

Holy mole

 

[Printer Bandit]

 

[Rubycon]

Seize this!

http://www.youtube.com/watch?v=I3f9Eh9qRYU

Imagine skeet shooting with these ampules in the middle of the ocean...

Pull!----boom-----BOOM!

:wub:

One has to wonder if a 300g ampule was dropped into the sea (gently enough to ensure it was not fractured on impact at the surface) and allowed to sink reaching sufficient depth to folding. Would the resulting explosion be sufficient to be realized at the surface?

 

[Rubycon]

https://www.youtube.com/watch?v=xEt5dEOcW0I

 

[PsiStar]

What if you had a mole of moles?
http://whatif.xkcd.com/4/

would that be a molol-plex? Sort of a googolplex

 

[ManBearPig]

That's the whole point. It is like that by construction, i.e., the mole was chosen to be what it is so this works out.

Yeah, I figured, but the sources I was looking at were so horribly written. Of course they can't just state it plainly.

 

[uclaLabrat]

Seize this!

http://www.youtube.com/watch?v=I3f9Eh9qRYU

Imagine skeet shooting with these ampules in the middle of the ocean...

Pull!----boom-----BOOM!

:wub:

One has to wonder if a 300g ampule was dropped into the sea (gently enough to ensure it was not fractured on impact at the surface) and allowed to sink reaching sufficient depth to folding. Would the resulting explosion be sufficient to be realized at the surface?

There wouldn't be any explosion if it was exposed to water at depth, as there isn't enough oxygen in the water to explode the hydrogen. It only explodes at the surface where the redox reaction provides enough heat to spark the hydrogen/oxygen combustion.

Any hydrogen released at depth as well as residual heat would be dissipated by the water.

 

[Rubycon]

There wouldn't be any explosion if it was exposed to water at depth, as there isn't enough oxygen in the water to explode the hydrogen. It only explodes at the surface where the redox reaction provides enough heat to spark the hydrogen/oxygen combustion.

Any hydrogen released at depth as well as residual heat would be dissipated by the water.

I suppose it really depends on depth that fracture occurs. If partially filled there isn't that much strength in the glass walls. At higher depth and corresponding pressure I can see the probability of H ignition reduced. Cs is violently reactive compared to the "lesser" alkali metals. If sufficient hotspots are created at the very least a phosphorescent type glow would be observed? Sounds like it would be an interesting experiment.

For now, I suppose launching the ampules from the stern, with a clay pigeon thrower, and shooting them with a light gauge shotgun so raw Cs contacts the water at the surface will have to do!

 

[The Boston Dangler]

 

[uclaLabrat]

I suppose it really depends on depth that fracture occurs. If partially filled there isn't that much strength in the glass walls. At higher depth and corresponding pressure I can see the probability of H ignition reduced. Cs is violently reactive compared to the "lesser" alkali metals. If sufficient hotspots are created at the very least a phosphorescent type glow would be observed? Sounds like it would be an interesting experiment.

For now, I suppose launching the ampules from the stern, with a clay pigeon thrower, and shooting them with a light gauge shotgun so raw Cs contacts the water at the surface will have to do!

It would definitely glow, I can only give an anecdotal story provided from my undergrad professor when he was in grad school at MIT and threw a chunk of sodium (somewhere between 1 and 5 pounds) in the charles river with his friends...it glowed bright orange at the bottom, and when it floated to the surface, set off a deafening explosion he claims broke a window a mile away.

 

[Rubycon]

It would definitely glow, I can only give an anecdotal story provided from my undergrad professor when he was in grad school at MIT and threw a chunk of sodium (somewhere between 1 and 5 pounds) in the charles river with his friends...it glowed bright orange at the bottom, and when it floated to the surface, set off a deafening explosion he claims broke a window a mile away.

Imagine how loud this was!

https://www.youtube.com/watch?v=HY7mTCMvpEM

 

[Farmer]

It would definitely glow, I can only give an anecdotal story provided from my undergrad professor when he was in grad school at MIT and threw a chunk of sodium (somewhere between 1 and 5 pounds) in the charles river with his friends...it glowed bright orange at the bottom, and when it floated to the surface, set off a deafening explosion he claims broke a window a mile away.

That's actually something they did every year at MIT (the college students, not the grad students), during freshman orientation, up until I think 2008, due to some legal issues (got into people's boats, the structural integrity of the Longfellow Bridge). It's called "sodium drop."

It is loud but it can't break any windows.

 

[BladeVenom]

I remember doing that. At the end of your lab session you had to give the lab teacher any left over sodium for "safe" disposal. The lab teacher was the only one who forgotten to wear his safety glasses, and the sodium blew up in his face.

 

[Lemon law]

Each carbon atom has 12 amu (6 amu from protons + 6 amu from neutrons).

1 g = 6.022 x 10^23 amu

1 mol = 6.022 x 10^23 atoms

Using those conversion factors, 12 amu/atom = 12 g/mol of Carbon

------------------------------------------------------------------------------------------
Which turns out to be exactly bullshit for for Carbon and many other elements on the periodic table. As James3shin is correct that a normal carbon atom has a mass of 6 protons, 6 neutrons, and six electrons. but still some carbon atoms have a extra two neutrons and hence is called carbon 14. But because Carbon 14 is radioactive and decays at a known rate to carbon 12, the remaining Carbon 14 becomes a fairly reliable clock. Which in turn is based on the fact, that carbon 12 in living vegetation will transform itself to a small fraction carbon 14 from mere exposure to sunlight. As that process will cease once the living vegetation dies. Which is why the carbon 14 carbon 12 ratio is a reliable clock for 6000 years or so. Other radioactive elements prove to be more reliable clocks dating back to billions of years ago.

Then if we want to go Einstein ballistic, we can point out that two Deuterium atoms combined together weights slightly more than one Helium atom. As the missing binding energy is converted to energy by the equation energy equals mass times MC squared. Oddly an fusion equation that only applies to all elements up to iron, after which fission is the other source of energy as it takes energy to fuse heavier elements.

Just my two cents that is probably only worth a cent. For my next lesson maybe we should talk about allotropic crystalline states of matter

 

[uclaLabrat]

------------------------------------------------------------------------------------------
Which turns out to be exactly bullshit for for Carbon and many other elements on the periodic table. As James3shin is correct that a normal carbon atom has a mass of 6 protons, 6 neutrons, and six electrons. but still some carbon atoms have a extra two neutrons and hence is called carbon 14. But because Carbon 14 is radioactive and decays at a known rate to carbon 12, the remaining Carbon 14 becomes a fairly reliable clock. Which in turn is based on the fact, that carbon 12 in living vegetation will transform itself to a small fraction carbon 14 from mere exposure to sunlight. As that process will cease once the living vegetation dies. Which is why the carbon 14 carbon 12 ratio is a reliable clock for 6000 years or so. Other radioactive elements prove to be more reliable clocks dating back to billions of years ago.

Then if we want to go Einstein ballistic, we can point out that two Deuterium atoms combined together weights slightly more than one Helium atom. As the missing binding energy is converted to energy by the equation energy equals mass times MC squared. Oddly an fusion equation that only applies to all elements up to iron, after which fission is the other source of energy as it takes energy to fuse heavier elements.

Just my two cents that is probably only worth a cent. For my next lesson maybe we should talk about allotropic crystalline states of matter

Say wha?

 

[OverVolt]

Say wha?

Just wait until he hits equilibrium again.

 

[Paperdoc]

I understand that all it is is a certain amount of "things." What I do not understand is how to go from carbon is 12 amu/atom to 12g/mol. I feel like a fucking retard! I understand all you have to do is just tack a "grams" on the end (basically), but I want to know how exactly I get from one unit to the other.

Thanks a lot for your help everyone!

There are two small steps to making this conversion.
1. "amu/atom" is the same a "grams per (Avogadro's Number of) atoms". So, for Carbon with an Atomic Mass of 12.011, one Avogaro's number of atoms of Carbon will weigh 12.011 grams.

2. Converting from atoms to moles requires knowing the composition of the molecule of this substance - the "chemical formula". For virtually all solid elements, we treat a molecule of it as just one atom. This is because a solid lump of only one pure element has all its atoms linked to each other in a huge matrix of shared electron bonds, and usually there is no special sub-structure of a fixed small number of atoms. So a Carbon molecule is just one Carbon atom, similar for Iron, similar for Sodium, similar for Plutonium, etc. But gaseous elements are normally very different, since they are NOT just atoms all linked together. Normally a gaseous element is composed of two atoms bound together into one molecule by sharing some electrons in a bond. So a molecule of Hydrogen is two such atoms, and hence its Molecular Weight is twice the Atomic Weight of one hydrogen atom. Thus the weight of one mole of Hydrogen gas is 2.016 g. A Chlorine molecule contains two chlorine atoms, and hence a mole (one Avogadro's Number of Chlorine molecules) weighs 70.906 grams. For molecules of several different atoms, you just need the molecular formula. Sodium Hydroxide is NaOH, so your Molecular Weight (the mass of an Avogadro's Number of NaOH molecules) in grams is just the sum of the Atomic Weights of the three atoms involved: (22.9898 + 15.9994 + 1.0080) = 39.9972. For Calcium Carbonate the formula is one Calcium plus one Carbon plus three Oxygen, and the Molecular Weight is 40.08 + 12.011 + 3x15.9994 = 100.0892. Well, make that 100.09, because the precision of the least-precise number (Calcium's Atomic Weight) limits us to two figures after the decimal point.

By the way, the Atomic Weights I used are funny numbers compared to most of this discussion - they are the actual Atomic Weights published in current tables. They are NOT simple integer numbers for two reasons. The small factor is that neutrons are not exactly the same mass a protons, and electrons are not completely without mass. The real factor, though, is relative abundance of different isotopes of each element. The accurate Atomic Masses are AVERAGES measured on real samples containing the "normal" mixtures of isotopes of these elements.

Oh, and the proper name for the quantity is "mole". We all shorten it to "mol" when writing units, just as we shorten "gram" to "g", and "millilitre" to "ml".