1 / 23

Extraction of Pure Elements from Nature

Extraction of Pure Elements from Nature. Which elements are easy?. Easy elements are gases that exist in the elemental form. N 2 , O 2 , noble gases Obtained by distillation of cooled, liquified air. Preview. Extraction of Metals.

jed
Download Presentation

Extraction of Pure Elements from Nature

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Extraction of Pure Elements from Nature Which elements are easy?

  2. Easy elements are gases that exist in the elemental form N2, O2, noble gases Obtained by distillation of cooled, liquified air.

  3. Preview

  4. Extraction of Metals All metals exist as cations in chemical compounds in the crust. Key: reducing the cations to the neutral metal. Example: Fe2O3 has Fe3+ ions. To obtain Fe metal, need to add 3 electrons to each Fe3+ ion.

  5. What we’ll find.

  6. Review of Thermodynamic Control of Reactions Enthalpy: H depends on bond strength reactions favored by negative H (which is forming stronger bonds) Entropy: S depends on randomness (disorder) reactions favored by positive S (increasing disorder, particularly formation of gases)

  7. Consider the decomposition of Fe2O3 Decomposition Reaction: 2 Fe2O3(s)  4 Fe(s) + 3 O2(g) Ho = So = Go = Temperature where Go is negative?

  8. Consider the reaction of Fe2O3 with C C(s) 0 5.6 CO2(g) -393.5 213 -394.4 Reaction with C: 2 Fe2O3(s) + 3 C(s)  4 Fe(s) + 3 CO2(g) Ho = So = Go = Temperature where Go is negative?

  9. Consider the decomposition of HgO 2 HgO(s)  2 Hg(l) + O2(g)

  10. Aluminum Production 2 Al2O3(dissolved) + C(s)  4 Al(l) + 3 CO2(g)

  11. Aluminum Production 2 Al2O3(dissolved) + C(s)  4 Al(l) + 3 CO2(g) Why use carbon instead of just a metal electrode? Go2 Al2O3(s)  4 Al(s) + 3 O2(g) = + 3164 kJ/mol Eo = Go2 Al2O3(s) + 3 C(s)  4 Al(s) + 3 CO2(g) = + 1981 kJ/mol Eo =

  12. Gold! 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l)  4 NaAu(CN)2(aq) + 4 NaOH(aq)

  13. Photography Chemistry Exposure: AgX  Ag(s) + X(s)

  14. Photography Chemistry Developing: AgX(s) + e-  Ag(s) + X-(s) HQ  Q + 2 H+ + 2e-

  15. Photography Chemistry Fixing: AgX(s) + 2 Na2S2O3(aq)  Na3[Ag(S2O3)2](aq) + X-(aq)

  16. Photography Chemistry

More Related