Chapter 2: Aqueous Chemistry Flashcards
H2O ; central oxygen forms what type of bond?
Oxygen forms covalent bonds with two hydrogen atoms. It leaves an unpaired pair of electrons.
Is water molecule polar or non-polar
Because water is in a tetrahedral arrangement it is POLAR
Hydrogen Bond
A weak electrostatic attraction between oppositely charged particles that have some covalent characters.
How many hydrogen bonds can a water molecule have.
Water can potentially participate in four hydrogen bonds. Because it has two hydrogen atoms to donate to a hydrogen bond and the two pairs of unshared electrons.
Ionic Interactions
Intermediate in strength to covalent bonds and hydrogen bonds
Van der waals interactions
weaker than hydrogen bonds. It is an interaction between two strongly polar groups is known as dipole-dipole.
Weak vander waals interactions ar also known as
London dispersion forces that occur between nonpolar molecules.
Dielectric Constant
measure of solvent’s ability to diminish the electrostatic attractions between dissolved ions. The higher the constant of the solvent the less the ions associate with each other
Polar water molecules surround water by aligning what?
They align their partial charges with the oppositely charged ions.
Solute
A dissolved particle
Why can water dissolve polar compunds
This is because multiple h bonds can be formed.
Glucose and other readily hydrated substances are said to be what?
Hydrophilic (water loving)
Compounds that lack polar groups are said to be what in wate
hydrophobic and insoluble
Polar substance is added to water
There is a loss in entropy because the highly mobile water has lost some of its freedom to rapidly form, break and re-form hydrogen bonds with other molecules.
The exclusion of nonpolar substances from an aqueous solution is known as the?
Hydrophobic effect
Adding more nonpolar molecules do what
They aggregate and the entropy of the system increases.
Most lipids are what type of -philic
Most lipids are amphiphilic or amphipatic. They experience both hydrophilic interactions and the hydrophobic effect.
Micelle
A sphere that has a hydrophobic core.
Bilayers
Amphiphilic lipids that provide a structural basis for biological membranes will from a two-layered sheet known as the lipid bilayer.
Lipid vesible
It forms to eliminate the solvent exposed edges.
Bilayer prevents diffusion of polar substances
Solutes that are within the vesicle will not be able to easily leave because of the lipid bilayer
Ionization of water formula
Ionization constant of water.
KW=K[H2O]=[H+][OH-], Kw=10-14
pH log formula
pH=-log[H+]
The Henderson-Hasselbalch Equation
The equation relates to the pH of a solution to the pK of an acid and the concentration of the HA and A-.
Buffer
Prevents dramatic changes in pH that would otherwise occur.
How buffers resist changes in pH
HCL→ H++Cl- large increase in [H+]
HCL + A-→ HA +Cl- Small increase in [H+]
The same can be applied to the strong base of NaOH. Buffer solutions resist pH changes because in this case some of the added protons combine with the conjugated base to reform the acid; no longer forms H. For NaOH the added hydroxide ions form more water and don’t contribute to the decrease of H.
Titration Curve
Before the acid or base is added. The midpoint is where the solution hits equilibrium (pH=pK). Afterwards the pH will change to either basic or acidic depending on the solution.
The bicarbonate buffer system
Elimination or retention of CO2 can shift the equilibrium in order to promote or prevent the loss of H+ from the body.
Bicarbonate reabsorption H+
Bicarbonate Production
