Tag Archives: practical

Let’s add oxygen, fluorine and neon gases

Oxygen from Theodore Gray's amazing book, The Elements
Oxygen from Theodore Gray’s amazing book, The Elements

This post concludes the Periodic Table Smoothie experiment.

Recall that we’ve just finished adding one mole of nitrogen gas and created a bizarre boron polymer at the bottom of our vessel. The temperature was 350 °C and the pressure in our vessel was 891 kPa.

Today, we’re going to add 1.00 mole of oxygen gas, stand back and observe.

Nothing happens.

This is disappointing news.

Many of the substances in our vessel react (more accurately, explode) in the presence of oxygen but the ignition temperature for all of those explosions to take place is at least 500 °C. The temperature of our vessel is set at just 350 °C. At this temperature, nothing would actually happen.

There’s not enough activation energy to break bonds in the reactant particles in order to get the reaction started. We call this activation energy (EA) in chemistry. If we were to add a source of excessive heat (e.g. a matchstick), the vessel would explode.

Should we heat up the vessel to 500 °C and blow up the experiment right here?

If we did, the following reactions would happen:

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Enough of these reactions – particularly the first three – are sufficiently exothermic to trigger a chain reaction – at least up to the reaction of oxygen with beryllium carbide. The vessel would bang, explode, and shatter. The helium would float away, dangerous lithium amide would fly out sideways, and polyborazine powder, whatever that is, would land on the floor.

Let’s not ignite our experiment – not yet.

Conclusion after adding 1.00 mole of oxygen gas

Substance Amount in mol
He(g) 1.000
Be(s) 0.514
LiH(s) 0.000
Li2C2(s) 0.272
B2H6(g) 0.000
Be2C(s) 0.175
H2(g) 0.007
BeC2(s) 0.136
CH4(g) 0.009
N2(g) 0.552
NH3(g) 0.154
LiNH2(s) 0.277
polyborazine 12.194 grams

Pressure: 891 kPa (higher than before due to the addition of nitrogen gas)
Temperature: 350 °C (vessel is still being maintained at constant temperature)

Oxygen was relatively uneventful. Let’s add fluorine and see what happens.

Let’s add fluorine gas

elements110009
Elements by Theodore Gray

The following three reactions would all occur as 1.00 mole of fluorine gas is added:

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These two products are quite interesting:

  • HF, hydrogen fluoride, an aqueous solution of which was used by Breaking Bad’s Walter White to dissolve evidence (his victims)
  • NF3, nitrogen trifluoride, is used as an etching agent when making printed circuit boards (PCBs)

Let’s add neon gas

elements110010
Elements by Theodore Gray

When 1.00 mole of neon gas is added, the total pressure inside the vessel increases but no reaction occurs. The concentrations of all the other gases present are unaffected.

The End

That concludes our Periodic Table Smoothie experiment. The most interesting conclusion was the discovery of polyborazine, the bizarre solid that collected at the bottom of the vessel.

Also of interest was how easily we created ammonia, one of the simplest of biological compounds, just by mixing elements together. Could the compounds necessary for life be so easy to create that their existence is an inevitable consequence of the Big Bang? Is life inevitable? If the Big Bang were to happen all over again, would life occur? And would it look any different?

Possibly not.

Periodic Table Smoothie

periodic table by randall monroe what if.png
Image from Randall Monroe’s excellent book, What If?: Serious scientific answers to absurd hypothetical questions

Yesterday, I was wondering what would happen if we mixed the entire periodic table of elements together in a blender. Unsurprisingly, it would explode, scattering radioactive dust and debris for miles around in a red-hot fireball formed from the simultaneous fission of the entire seventh row. The periodic table would only need to be the size of a matchbox in order for this explosion to happen.

Calculating exactly what would happen would be incredibly difficult. There are so many simultaneous reactions – including nuclear reactions – taking place that it’s almost impossible to predict the outcome in any more detail than “KABOOM”.

Making a real Periodic Table Smoothie  would be prohibitively expensive. You’d need 118 particle accelerators (costing $1 billion each) all pointing at the same target just to get single atoms of each element to collide at the same time. This is even more difficult than it sounds: those elements near the bottom of the periodic table (numbers 105 and above) are so unstable that they’d break down before they even reach the target. There are massive financial and physical challenges to mixing an entire periodic table up in a blender.

Instead of adding all the elements at the same time, I’ll be adding one element each week to an imaginary 10-litre vessel and documenting – as a theoretical exercise – what happens. Ultimately, we all know it’s going to explode at some point. But when will it do that? How many elements are we able to add before it finally explodes? Will we create anything interesting along the way?

This very idea was floated on Reddit’s AskScience forum in 2013 but nobody actually figured out (seriously) what would happen.

Join me next week to start the experiment.

periodic table smoothie on reddit.jpg