Extraction of Pure Elements from Nature

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

9. Consider the decomposition of Fe2O3 C(s) 0 5.6 CO2(g) -393.5 213 -394.4 Reaction with C:

11. Consider the decomposition of HgO

16. Aluminum Production

20. Gold