1 How does energy move through the environment and life?Data Lecture for A World from Dust Chapters 4-6

2 The Second Law says both of these slopes are positive:Any system that has not been maximized in entropy allows us to do work Note that you can only do work by increasing the entropy of the universe! Fig 16.3 BCtL p. 492

3 The bulk of the earth generates entropy by heat radiationLight from the sun (few large quanta)  heat (lots of small quanta, DISPERSED!) This is such a huge effect that local order is relatively minor, and entropy increases (and work is done) despite organization. The tendency of the universe to increase entropy is fulfilled when an organized structure releases heat. NSoCE p.112.

4 A multi-layered device can take advantage of the spreading out of energy

5 Infrared antennae could capture this heat

6 A heat engine intercepts movement from hold to cold to do work (e. gA heat engine intercepts movement from hold to cold to do work (e.g., by turning a dynamo); An infrared rectenna uses it to move electrons

7 Hot stuff gives off light: Star colors come directly from their temps

8 Whether hydrogen or iron, hot stuff glows the same colorYou can tell the temperature of an iron pan from its color:

9 Two things heat the earth: its own core and the sunThe sun = 50-60K added to surface temp Radioactive decay = 40K added to surface temp The rest comes from the core’s own heat The fact that the earth is tilted causes uneven heating between north and south, which results in west-east winds like the Jet Stream

10 Note the temperature column: nearly constant!2010 ref: even in this period oceans may have been <40°C! Also note that these are ALL accessible temps anywhere on the crust (including deep sea vents or, in the last case, in laboratories) Vol 464| 15 April 2010| doi: /nature08952

11 The early earth’s conditions moved directly toward what special point?Water is “constrained” to be liquid at STP

12 Most other simple/abundant molecules are not liquid in the earth’s temperature rangeWater is special (and it has H-bonds too) Formamide

13 How will ions behave in the oceans. Ion pairs form lattices with ΔHf 1How will ions behave in the oceans? Ion pairs form lattices with ΔHf 1.5 times the ΔHf of pairing up (in gas) This lattice cooperativity is why things will precipitate out of solution Notice how it only depends on the radii of the charges It only matters how BIG the ions in the lattice are (and what their charges are)

14 Want to know solubility? Measure a KspK for this reaction: precipitate  ions

15 Different metals dissolve differently in oxygen-rich vsDifferent metals dissolve differently in oxygen-rich vs. sulfur-rich oceans Compare the KSP of the sulfide to the oxide In ocean after acid was titrated out and H2S dissolved, Co, Cu, and Zn precipitated out. Mn, Mg, and Ca were present at the time but would precipitate more when oxygen increased. Fe and Ni are very similar and “in the middle”: should be around sparingly both in S-rich and O-rich times

16 ΔHf of sulfides vs. oxides gives a similar conclusion

17 Other metals hogged all the O, and Fe was left as FeS or other alloys

18 Why does burning anything always release energy. (Or, why is fire hot

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20 TYPO!!!

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22 Combustion of a general C, H, O-containing moleculeLosing bonds to carbon Gaining bonds to oxygen, which is proportional to amount of O2 in rxn

23 Don’t forget heat of condensation of H2O

24 All combustions give more enthalpy if they involve more oxygen

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26 Bring 2 questions on Wednesday (written)Preferably one for discussion (no answer necessary), and one for homework (with answer) Involving the topics from Chapters 4-6 of AWfD Possibly using data or concepts from today? We will discuss what you wrote in the first half-hour of class (And if I like a HW question I may write it into the test!)

27 The other elements were left out of the metallomeNotice that metals on the right side of the periodic table have greater hydration enthalpies Because of these enthalpies, these elements are more stable in water and more useful for life The other elements were left out of the metallome Ca must be special somehow …

28 Geochemists looked at Fe and Ni in banded iron rocks in AustraliaThey found that the Ni/Fe ratio dropped off a cliff 2.7 billion years ago, just as the lava temperature cooled past 1500ºC

29 A modest proposal: The lava got too cool to carry NiSo the methanogens ran out of Ni and had to retreat to Ni-rich areas starting 2.7 billion years ago. They had no choice: Ni kinetics are slow and its loss can’t be fixed with greater uptake Then, 2.4 billion years ago, the Great Oxidation Event happened. Guess the (lack of) Ni was the chicken and the O2 was the egg! Black line: [Ni] in ocean vs. age