Introduction to Water

1. Introduction to Water

2. Soil and Water evaporation Created by Dr. Michael Pidwirny, Department of Geography, Okanagan University College, BC, CA

3. What is Soil? The interface between the atmosphere, hydrosphere, biosphere and lithosphere naturally occurring layers of mineral and organic constituents that differ from the underlying parent material in their physical, chemical, and mineralogical properties Rock

4. What is Water? A binary compound that occurs at room temperature as a clear colorless, odorless, tasteless liquid Freezes into ice below 0 C and boils above 100 C Necessary for life on earth (human, animals and plants) Constitutes 60-70 % of the humanbody www.atpm.com

5. Electro positive Hydrogen Hydrogen H-O : 0.97 A H-H : 1.54 A 1050 Oxygen Polarity angstroms Negative Symmetrical (e.g., CO2)

6. Hydrogen bond H+ O-- - H2O = + H+ Gives structural strength Bond depends on temperature: Bonds are weaker at higher temperature Positive end attraction with neg. end of other water molecules

7. Dipolar nature of water due to unevenly distributed charges http://www.chem1.com/acad/sci/aboutwater.html

8. Polymer type of grouping H+ H+ O= Cations: Na+, K+, Ca2+ become hydrated through their attraction to the negative end of water (Oxygen side) Anions or negatively charged clay surfaces attract water through positive hydrogen side

9. J. L. Fulton, Y. Chen, S. M. Heald, and M. Balasubramanian, Rev. Sci. Instruments., 75(12), 5228-5231 (2004). http://www.pnl.gov/cmsd/highlights/images/20050727water.jpg

10. http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-1/water-structure.jpghttp://courses.cm.utexas.edu/jrobertus/ch339k/overheads-1/water-structure.jpg

11. Does water swell and shrink with Temperature? 1 0.998 40C 0.996 0.994 0.992 Density (g cm-3) 0.990 Temperature (0C) -10 0 20 10 30 40 50

12. http://www.columbia.edu/cu/biology/courses/c2005/ purves6/figure02-15a.jpg www-ssrl.slac.stanford.edu/.../structure_ice.jpg

13. Representation of Ice Melting www.cscs.ch/.../representations/index.html

14. groups periods Dimitri Mendeleev

15. Temperature range in liquid phase for H2x compounds 100 Boiling point Freezing point H2O (2+16=18) 50 Hydrogen telluride Temperature (0C) 0 H2Te (130) Hydrogen sulfide H2Se -50 (80) H2S Hydrogen selenide (2+32=34) -100 0 50 100 Molecular Weight The sum of the atomic weights of all atoms in a molecule

16. If water were an ordinary compound whose molecules are subject to weak forces, its boiling and freezing points would fall below hydrogen sulfide Strong hydrogen bonding between water molecules prevents this so that liquid water acts more like a gel, cluster, or polymer Water occurs in all three states (solid, liquid, and gaseous) at prevailing temperatures on the earth’s surface Example: Ice cubes in a glass at room temperature

18. Soil Solution aqueous liquid phase of the soil and its solutes

19. Hydrogen Bonding

20. Water is a powerful solvent How salt dissolves in water nutrition.jbpub.com/.../chemistryreview6.cfm

22. How do plants obtain the nutrients in the soil? http://www2.mcdaniel.edu/Biology/botf99/nutrition/catex.jpg

23. www2.mcdaniel.edu/.../botf99/nutrition/soils.htm

24. Clay minerals as sources of ions http://www.ca.uky.edu/agc/pubs/agr/agr11/fff00003.gif

25. Typical ion concentrations (can be much higher in arid regions due to high evapotranspiration (ET) and concentrating effects) K+ 1-10 (mg/L) Na+ 1-5 Ca+2 20-200 Mg+2 2-50 Si+4 10-50 SO4-2 60-300 Cl- 50-500

26. Solutes exist in solution as: • Free hydrated ions • Complexes with ligands organic or inorganic (H2O, NH3+, F-, OH-, Cl-, CN- or EDTA, citric acid, DTPA, NTA,…)

27. “Free” hydrated ions

28. Metal-ligand complexes http://www.freepatentsonline.com/7115549-0-large.jpg http://journals.iucr.org/e/issues/2006/11/00/ng2089/ng2089scheme1.gif

29. Ligand Exchange Mechanisms[ ML6 + Y- ML5Y + L- ] www.meta-synthesis.com/.../mechanism.html