Intro Flashcards
Thermodynamics
predicts whether a particular chemical reaction can occur
Kinetics
information about the speed of reaction
Gibbs Free Energy
Energy (enthalpy) and/ or Entropy driven
delta G = deltaH = TdeltaS
Delta G is negative
Soil Processes: Intraphase
changes in element speciation within a phase
Soil Processes: interphase
transfer of matter between phases; ex- CO2 to plant biomass to SOM
Soil chemical POV: Multiphase
porous materials whose voids contain air and solution
Soil chemical POV: Multicomponent
soil matrix, soil air, and soil solution are each a mixture of reactive chemical compounds
Soil Chemical POV: open
exchange both matter and energy with the surrounding atmosphere, biosphere and hydrosphere
Soil Chemical POV: biogeochemical
biological and chemical transformations link soils with the atmosphere and hydrosphere producing fluxes that are of global significance
Electronegativity
increases bottom-up and left to right
Atomic radii
increases top to bottom and right to left
covalent bonding
sharing of electron pairs; occur between atoms of similar electronegativity; strongest 50-100 kcal/mol; short ranges; increases bond order proportional to increased strength of covalent bond
ionic bonding
occur between ions of opposite charge; opposite end of the periodic table; relatively strong bonds; long-range bonds; COMMON FOR SOIL MINERALS
If the ionic character % is 51 what does that mean
is means that the bonds are more covalent
ion-dipole bonding
shorter range; related to r^2; weaker than ionic and covalent
Dipole
a separation of charge within a molecule; ex water molecule
examples of ion-dipole forces
cation and anion hydration in water- Al3+ will hydrate more strongly than K+ because it has a more dense charge radius
dipole-dipole bonding
occurs by orienting oppositely charged ends towards one another
H-bonding
weak electrostatic bond between H and highly electronegative atoms (N, O, Cl, F)
Van Der Waals forces
weak attraction between nonpolar/apolar molecules; imbalances in electron distribution produce instantaneous dipoles; extremely short range
The hydrophobic effect
The exclusion of nonpolar substances from an aqueous solution
aggregation of hydrophobic molecules does what
frees up water molecules to increase the configural entropy of the system
amphiphilic
assembly (molecules with both hydrophobic and hydrophilic portions): micelles, lipid bilayers, vesicles, proteins.
bonding is rarely exclusively one of a kind
in soil minerals most bonds are composite of both covalent and ionic character
