BCH 441 FINAL REVIEW EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED
strength of weak interactions
van der waals: 0.4-4.0 kJ/mole
Hydrogen bonds: 12-30 kJ/mole
Ionic bonds: 20kJ/mole
Hydrophobic Interactions: <40kJ/mole
Structure of water
2 slightly positive hydrogen atoms, 1 slightly negative oxygen atom
Dipole Moment in a Water Molecule
corresponds to the O-H bonds having 33% ionic character
the dipole moment of water points
negative to positive
What are the properties of water?
-high boiling point
-high meltng point
-high heat of vaporization
-high surface tension
-bent strucuture makes it polar
-non-tetrahedral bond angles
-H-bond donor and acceptor
-potential to form four H-bonds per water
, Henderson-Hasselbalch equation
pH = pKa + log [A-]/[HA]
buffer action
the ability of an acid-base mixture to resist sudden changes in pH
Laws of Thermodynamics
1.) energy of a closed system is conserved
2.) systems tend to proceed from ordered to disordered
3.) at 0K the entropy (S) of a perfectly ordered crystalline substance is zero
what is free energy
hypothetical quantity used by scientists to assess whether a reaction will occur
spontaneously or not
Gibbs free energy
The energy in a system that can be used to drive chemical reactions.
Gibbs free energy equation
ΔG = ΔH - TΔS
for any process at constant P and T
ΔG = ΔH - TΔS
If delta G = 0, the reaction is
at equilibrium
If delta G < 0 then the reaction
proceeds as written
why are amino acids uniquely suited to their role as the building blocks of
proteins?
WITH COMPLETE SOLUTIONS VERIFIED
strength of weak interactions
van der waals: 0.4-4.0 kJ/mole
Hydrogen bonds: 12-30 kJ/mole
Ionic bonds: 20kJ/mole
Hydrophobic Interactions: <40kJ/mole
Structure of water
2 slightly positive hydrogen atoms, 1 slightly negative oxygen atom
Dipole Moment in a Water Molecule
corresponds to the O-H bonds having 33% ionic character
the dipole moment of water points
negative to positive
What are the properties of water?
-high boiling point
-high meltng point
-high heat of vaporization
-high surface tension
-bent strucuture makes it polar
-non-tetrahedral bond angles
-H-bond donor and acceptor
-potential to form four H-bonds per water
, Henderson-Hasselbalch equation
pH = pKa + log [A-]/[HA]
buffer action
the ability of an acid-base mixture to resist sudden changes in pH
Laws of Thermodynamics
1.) energy of a closed system is conserved
2.) systems tend to proceed from ordered to disordered
3.) at 0K the entropy (S) of a perfectly ordered crystalline substance is zero
what is free energy
hypothetical quantity used by scientists to assess whether a reaction will occur
spontaneously or not
Gibbs free energy
The energy in a system that can be used to drive chemical reactions.
Gibbs free energy equation
ΔG = ΔH - TΔS
for any process at constant P and T
ΔG = ΔH - TΔS
If delta G = 0, the reaction is
at equilibrium
If delta G < 0 then the reaction
proceeds as written
why are amino acids uniquely suited to their role as the building blocks of
proteins?
