topic 1 Flashcards
what is Brownian motion?
the constant random movement of water due to thermal energy which powers molecular interactions
what are the noncovalent interactions? why are they important?
ionic, HB and van der waals
-all of the noncovalent bonds are critical in the formation of tertiary structures.
-HB is the foundation of forming secondary structures as they allow for transient interaction between polypeptides
how does water influence the formation of non covalnet bonds?
due to its high dielectric constant, it is able to disassociate salts
they participate in the formation and breakage of HB
power van der waals interactions via the formation of asymmetrical transient eletrectic distribution within non polar molecules
what is columbs law?
E=Kq1xq2/Dr
q are the relative charges (abs) of the salt
K is a constant
D is dielectric
r is the distance between moles
a larger Dr value means a weaker bond strength, tf a higher dissolution rate in the given solvent
what is the energy and distance between covalent bonds
418kJ (strong)
0.9A
what is the energy and distance between ionic bonds
6-30 kJ
3A
what is the energy and distance between HB bonds
8-20kJ
3A
what is the energy and distance between Van der walls bonds
2-4kJ
3-4A
note that Van interactions become effective in numbers
what is the hydrophobic effect?
the tendency for nonpolar hydrophobic molecules to accumulate while in a polar aqueous solvent. this obeys the 2nd law of thermodynamics, where the entropy of the water increases when the non-polar molecules are ‘removed’ from the solvents environment
how to calculate the pH of water
14=pH+pOH
10^-14=[H+][OH-]
henderson hassbalck eq
ph=pka+log([A-]/[HA])
ph= log(1/[H+])
pka=log(1/ka)
how to calc the ka value
ka= ([H+][A-])/[HA]
what is a buffer
a mixture of a weak acid and a conjugate base which works to resist the change of a ph in solution
how is HB formed
by which a, e- deficent H is adjacent to an X neg atom, such as N,O or F.
