Practice Problems 9
Hydrogen-deuterium (H-D) exchange studies on proteins provide information about the
exposure of amide protons to the solvent. The protein content of rod outer segment membranes
(ROS) contains 85% of the protein rhodopsin.
Anandamide block the
runners high in mice
even after prolonged
Mice can display symptoms of runners
highless anxiety and a diminished
ability to feel painstudy suggests.
After a nice long bout of aerobic exercise,
Kinetics and Inhibition
Studies of enzyme inhibition are very
valuable because they give
information on the active site of an
enzyme, its mechanism of action and
possible mechanisms of regulation.
This is of p
Practice Problems 5
From the figure shown below, explain how Planck concluded that the classical theory for
blackbody radiation works only at low frequencies and not high frequencies?
Answer: In this figure, energy radiated by the bl
PRACTICE PROBLEMS 1 SOLUTIONS
1. Circle TRUE or FALSE:
If the exponential decay of the reactant in a first-order reaction is as shown, we conclude
that the larger the rate constant the more rapid the decay.
For a reaction A B, that has an
equilibrium constant of 10, what can be
said about the reaction rates ?
Ans: Nothing can be said about the magnitudes of
the individual rates. The only thing you can conclude
is that the rate constant for the forward reacti
Chemistry 122 1/27/2014
Energetics of Solution Formation
The solution process is accompanied by changes in enthalpy. Example: when NaCl
dissolves in H2O, the process is slightly endothermic Hsol = 3.9 kJ/mol.
Three processes affect the energetics of solut
Chemistry 121 2/28/2014
Changing the reaction conditions: Le Chteliers Principle
Obtaining the maximum amount of product from a reaction depends on the proper
selection of reaction conditions.
By changing these conditions, you can either increase or decre
Chemistry 121 2/17/2014
14.6 Reaction Mechanisms
The sequence of events that describes the actual process by which reactants become products is
called the reaction mechanism.
Reactions may occur all at once or through several discrete steps.
Chemistry 2 3/5/2014
These are the pH values of several common substances
An aqueous solution has a pOH of 10.24. Calculate [H+].
We need to calculate [H+] from pOH.
pH + pOH = 14.00, to calculate pH from pOH.
pH = 14.00 pOH
pH = 14.00 10.24 = 3.76
pH = l
Chemistry 2 3/12/2014
16.8 Relationship between Ka and Kb
Lets consider the NH4+ and NH3conjugate acid-base pair:
NH4+ (aq) NH3 (aq) + H+ (aq)
NH3 (aq) + H2O (l) NH4+ (aq) + OHH2O H+ (aq) + OH- (aq)
Therefore, if you know one of them, you can calculate th
Chemistry 121 3/7/2014
Exam Review sessions
Adc Plus LC 1 4:15-5:45pm
LC 23 6-7pm
Ka= [H+][A-]/ [HA]
HA H+ + A-
Weak Acids: Dissociation Constants
Most acidic substances are weak acids, they are partially ionized.
For a generalized acid dissociation,
Chemistry 2 3/3/2014
Chapter 16: Acid-Base Equilibria
We tend to think of acids as scary liquids found in laboratories and industrial
processes. Although this picture is partially true, it is far from complete.
We interact with acids on a daily basis.
Chemistry 121 2/26/2014
15.6 Applications of equilibrium constants: Predicting the direction of Reaction
Consider the formation of NH3 from N2 and H2, 1 mol of N2 and 2 mol of NH3 in a 1-L container.
How will the mixture react to reach equilibrium?
Chemistry 121 2/24/2014
The Equilibrium Constant Kp
Since pressure is proportional to concentration for gases in a closed system, the equilibrium
expression can also be written
Kp = (PC)c (PD)d / (PA)a (PB)b
aA+ bB cC + dD
Relationship between Kc and Kp
Chemistry 122 1/31/2014
Osmosis is the movement of solvent molecules through a semipermeable membrane
to equalize solution concentrations on both sides of the membrane.
In osmosis, there is net movement of solvent from the area of higher solvent
Chemistry 122 1/24/2014
A solution is made by dissolving 4.35 g glucose (C6H12O6) in 25.0 mL of water at 25 C.
Calculate the molality of glucose in the solution. Water has a density of 1.00 g/mL.
*look at class notes for solution process*
Step 1: Write do
Chemistry 122 1/29/2014
Liquids boil when the vapor pressure (VP) equals to the air pressure of the surroundings, so a
lower VP means a higher boiling point
Due to solute- solvent intermolecular attraction, higher concentrations of nonvolatile solutes
Chemistry 122 2/7/2014
14.4 Integrated Rate Laws: Concentration changed over time
The rate laws discussed so far tells us the rate or concentration at a given instant.
These law can be transformed into integrated rate laws which include time as a variab
Chemistry 122 2/10/2014
Exam chapter 13 and 14
Everything up to chapter 14.5 is in the exam
Molecules must collide with the orrect orientation and with enough energy to cause bond
breakage and formation.
The collision Model
Reaction rates are affecte
Heterogeneous catalyst: This involves the use of a catalyst in a different phase from the
One way a catalyst can sped up a reaction is by holding the reactants together and helping bonds
H2O= CH2 (g) + H2 (g) Pd/Pt
Chemistry 122 2/3/2014
For the following reaction: A B
Suppose the concentration of A changes from 1.2 mol/L (conc A1) to 0.75 mol/L ( conc A2)
over a 125-s period. The average rate is:
A. 5.0 x 10-5 mol/ L*s
B. 3.6 x 10-3 mol/L*s
C. 2.5 x 103 mol/ L*s
17.1 The Common-Ion Effect
Consider a solution of acetic acid:
CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO(aq)
To this solution we add CH3COONa sodium acetate. If acetate ion is added to the
solution, Le Chtelier says the equilibrium will shift to the left.
Chemistry 121 3/14/2014
Factors Affecting Acid Strength
1. The more polar the HX bond, the more acidic the compound. A molecule containing H
will behave as an acid only if the bond is polarized this way:
Hydrides such as NaH, do not react as acids, becaus
Chemistry 2 5/2/2014
Organic chemistry is the chemistry of carbon compounds.
Carbon has the ability to form
Without this property, large biomolecules such as proteins, lipids, carbohydrates, and
nucleic acids could not form.
Chemistry 2 4/25/2014
3. Magnetic Quantum Number (ml)
The magnetic quantum number describes the three-dimensional orientation of the orbital.
Allowed values of ml are integers ranging from l to l:
l ml l
4. Spin Quantum Number (ms)
This quantum number ref
Problem solving Chemistry 4/25/2014
Cu2+ + 2e- Cu(s)
2H2O O2 + 4H+ 4eReduced constant current for five hours
What is the current?
Current= Charge/ time
Time= 5 hours
.404g x (1 mol Cu)/(63.6g) x (2 mol e-/ 1 mol Cu) x (9.6485x 104 C/ 1 mo
Chemistry 2 4/30/2014
Writing Lewis Structures
The best Lewis structure
Is the one with the fewest charges.
Puts a negative charge on the most electronegative atom.
Some molecules are not well described by just one Lewis structures.