Friday 29 November 2013

Isotopes

In discussions and blogs, I have concluded that people do not understand Isotopes.   So they think Carbon 12, Carbon 13, Carbon14 are somehow different chemically.

Rule: Isotopes are identical chemically.

In the nucleus there are two near identical types of big particles, protons with a positive charge and neutrons which are neutral. (the modern count of subparticles is in the hundreds.)   In forming all the atoms on the planet you can have endless mixes of protons and neutrons from Hydrogen with a single proton to Uranium
with 92 protons and 146 neutrons (for U238).

Rule: the nucleus plays no part in chemistry and chemistry cannot touch the nucleus
The number of protons determines the chemistry as it exactly matches the number of electrons, 6 for carbon, 92 for Uranium.   The nucleus has nothing to do with chemistry otherwise.  It is simply not involved in any chemical reaction but provides 99.9% of the weight of an atom.

Rule: the only measurable difference between isotopes is weight
Isotopes cannot be separated chemically.   The only measurable difference is in the slight weight.   For example, to separate fissile Uranium 235 from the 99.5% of Uranium 238, Iran needs hundreds of very high speed centrifuges.   That does not mean you cannot in special circumstances find a difference, especially with light weight atoms like Carbon, but it is very slight and weight based, not chemical reaction based.

Note all isotopes of a given element have the same name, say Carbon or Uranium or Iodine.   Isotopes are variants of an element with different weight.

Rule: Atomic weight is made up of isotopes
If Carbon had 6 protons, 6 neutrons, a 'mole' of carbon atoms should weigh 12.000000 amu (Atomic mass units)  However it weighs 12.01 amu.  That is because it is 99% weight 12 and 1% weight 13.

Rule: Stable or unstable
Isotopes can be stable or unstable.   C14 is created by cosmic rays and it is unstable.   In 5740 years, half of the atoms will have reverted to N14, when a neutron changes to a proton, emitting an electron.  In another 5740 years, half of the balance will have exploded, leaving only 1/4 and so on.

Rule: Carbon 14 is incredibly rare
Carbon 12 is stable and 99% of all carbon.   C13 is stable and 1%.   C14 is 1 x 10-12%, so one millionth of a millionth of 1%.  If total CO2 is a massive 100,000 billion tons, C14O2 is only one ton.

Rule: Mixed as shown by the bomb graph, what happens to C14 happens to all CO2.

Notes:
1. C12/C13 ratios.  There are people trying to draw conclusions from the variability of the ratio of the 1% C13 atoms from the 99% C12 atoms.   The variation in this ratio is about 0.15%  or about one part in 600 from dead constant.   Clearly there are subtle differences in behavior of the heavier C13O2 (45) against the lighter C12O2(44) and conclusions can be drawn which are useful.   However they are not as conclusive as doubling C14 and watching it disappear.  For some reason, authors tend to dismiss C14 as good only for radiocarbon dating.  In this they are quite right.   We can radio carbon date the air itself.

2. Those people who try to argue that CO2 made from Carbon 14 is treated dramatically differently in the environment need to appreciate that chemically, this is not possible.   What happens in the bomb graph to C14 in the form of CO2 is that it vanishes somewhere, never to appear again.   This means the air with which it was associated also disappears, which gives a half life of 14 years for the total absorption of all CO2 into the huge oceans.   There is no debate on this.   IPCC predictions of 250 years, predictions which allow fossil fuel to hang around, are completely at odds with the observed fact.   The world's biggest nuclear experiment has proved them wrong.    Those who argue that the C14 laden CO2 is simply exchanged have to explain why this would happen, why the law which covers the exchange does not maintain the old CO2 ratio between air and sea.

3. You cannot increase CO2 in the air if temperature and pressure do not change.
No, man made CO2 disappears into the oceans because it is excess to the equilibrium value, so it just goes.
This was deduced by the early C14 radiocarbon dating people to explain the Suess effect, where C14 was very slightly diminished before the bombs, not the 30% people would have you believe but less than 1%.
The disappearance of the C14 shows the operation of a very fast equilibrium system.   This means it is maintaining a level of equilibrium.   The level of CO2 in the air is set by Henry's law across the planet and maintained by it.  The concept that man can fool Henry's law is absurd.



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