MCAT Audio Osmosis with Jordan and Jon Known Erratta
By Jordan Z. from Exam Krackers. Formatting by LifetimeDoc. Updated January 8, 2006
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CD #3 Track #17 Physics Lecture 5: Fluids ?Surface Tension
The terms 'cohesive' and 'adhesive' are reversed when Jordan says:
The cohesive forces of water to glass are greater than the adhesive forces of water to water. The cohesive forces can cause a water column to climb the glass of a thin test tube. This is called capillary action. If the adhesive forces are stronger than the cohesive forces, like mercury in a glass test tube, the miniscus is convexed and will be pulled downward in a thin test tube.
He should have said:
The adhesive forces of water to glass are greater than the cohesive forces of water to water. The adhesive forces can cause a water column to climb the glass of a thin test tube. This is called capillary action. If the cohesive forces are stronger than the adhesive forces, like mercury in a glass test tube, the miniscus is convexed and will be pulled downward in a thin test tube.
All other references to cohesive and adhesive are correct.
Cohesive forces are the forces between molecules within the fluid, such as water-to-water forces. Adhesive forces are the forces between the molecules of the fluid and the container, such as water-to-glass.
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CD #4 Track #2 Physics Lecture 7: Electricity and Magnetism ?Electrostatic Force
Coulomb's law constant is 8.9x109 not 8.9x10-9.
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CD #4 Track #18 Physics Lecture 8: Light and Optics ?Geometric Optics
When discussing the critical angle Jordan says
If the light is moving from a lower index of refraction to a higher index of refraction...
He should have said:
If the light is moving from a higher index of refraction to a lower index of refraction...
Total internal reflection occurs when light tries to move from a medium with a HIGH index of refraction to a medium with a LOW index of refraction and the angle of incidence is so great that all the light is reflected back into the high indexed medium.
In the same discussion, Jon says when solving for the critical angle with Snell's law
The larger index of refraction must be on the top of the ratio.
He should have said:
The larger index of refraction must be on the bottom of the ratio.
The opposite is true. The larger index of refraction must be on the bottom of the ratio, so that the ratio is a fraction less than one.
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CD #5 Track #7 Verbal Reasoning ?Verbal Strategy Part 4: Timing
Stand alone timers are no longer allowed on the MCAT. You are limited to a watch.
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CD #6 Track #5 Chemistry Lecture 2 continued
?Chemical Equilibrium
Jon says
The equilibrium expression changes with temperature, but is not affected by a catalyst or by concentrations.
He should have said
The equilibrium constant changes with temperature, but the equilibrium expression does not. Neither the equilibrium expression nor the equilibrium constant is affected by a catalyst or by concentrations.
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CD #6 Track #15 Chemistry Lecture 3: Thermodynamics ?Radiation
Jordan says that the net heat transfer rate is proportional to...
the temperature difference between the body and the environment raised to the fourth power. Net heat transfer = sigma*epsilon*A*(T4 - Te4).
The net heat transfer is actually proportional to T4 - Te4 not (T-Te)4
At low temperature differences, Newton's law of cooling says that the rate of cooling of a body is approximately proportional to the temperature difference between the body and the environment.
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CD #7 Track 2 Chemistry Lecture 5 continued
?Thermodynamics of Phase Change
While discussing melting Jon says
It is interesting to relate thermodynamics to the heat curve... ...But the enthalpy change is negative
Jon should have said
It is interesting to relate thermodynamics to the heat curve... ...But the enthalpy change is positive
Both enthalpy change and entropy change are positive during melting. Everything else in the track still applies. If both entropy and enthalpy change are positive, delta G depends upon temperature.
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CD #7 Track #8 Chemistry Lecture 6: Acids and Bases ?Definitions
Jordan says
Lewis acids: donate; bases: accept.
This is backwards.
Lewis acids: accept; bases: donate.
Lewis acids accept a pair of electrons and Lewis bases donate a pair of electrons.
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CD #7 Track #10 Chemistry Lecture 6: Acids and Bases ?Acid Strength and pH
Jordan says that the pH of a solution with a hydrogen ion concentration of 3.6x10-4 is pH = 4.5. It is pH = 3.5.
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CD #7 Track #11 Chemistry Lecture 6: Acid and Bases ?The Log Function
Jordan says
The log of A times B equals the log A times the log of B.
He should say
The log of A times B equals the log of A plus the log of B.
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CD #7 Track #26 Chemistry Lecture 7: Electrochemistry ?Redox Titrations
Jon says
..the arteriole red blood cells contain fewer chloride ions than venous red blood cells.
If Jon had been thinking correctly he would have said
..the arteriole red blood cells contain MORE chloride ions than venous red blood cells.
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CD #7 Track #30 Chemistry Lecture 7: Electrochemistry ?Gibbs Free Energy and EMF
Jordan says
If delta G zero is positive, K is greater than one. If delta G zero is negative, then K is less than one.
?
Jordan should have said
If delta G zero is positive, K is less than one. If delta G zero is negative, then K is greater than one.
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CD #8 Track #23 Biology Lecture 2: Genes ?Translation
Jon says
...dragging the second tRNA to the P site, and exposing the P site for yet another tRNA.
?
Jon should have said
...dragging the second tRNA to the P site, and exposing the A site for yet another tRNA.
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CD #8 Track #23 Biology Lecture 2: Genes ?Translation
DNA and RNA are read 5 to 3. Anticodons are an exception and they are read 3-5. This track says that the anticodon is read 5 to 3. This is incorrect. This knowledge is very unlikely to be tested by the MCAT.
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CD #9 Track #50 Biology Lecture 5: The Endocrine System ?Embryology
They say that the oocyte undergoes meiosis 1 and 2 after penetration by the sperm.
This is incorrect for humans. The correct process is as follows:
Oogenesis begins in the ovaries of the fetus. All the eggs of the female are arrested as primary oocytes at birth... ...Shortly before the primary oocyte is released from the follicle during ovulation, the nucleus divides by meiosis to become the secondary oocyte... ...The entry of the sperm causes the cortical reaction, which prevents other sperms from fertilizing the same egg. Now the oocyte goes through the second meiotic division releasing a second polar body. Fertilization occurs when the nuclei of the egg and sperm fuse to form the zygote.
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CD #10 Track #8 Biology Lecture 6: The Digestive System ?Absorption
Jon says
nutrients are absorbed into the enterocytes of the small intestines mainly in the DUODENUM
?
Jon should have said
nutrients are absorbed into the enterocytes of the small intestines mainly in the JENUNUM and ILEUM whereas digestion is performed mainly in the DUODENUM.
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CD #12 Track #3 Organic Chemistry Lecture 2 continued
?Electrophilic Addition
Halogenation
Jordan says
Isn't there a way to add the halogen to the MOST substituted carbon? and Jon says, with peroxides... HYDROGEN adds the most substituted carbon.
?
Jordan should have said
Isn't there a way to add the halogen to the LEAST substituted carbon? and Jon says, with peroxides... HYDROGEN adds the most substituted carbon.
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CD #12 Track #6 -- Organic Chemistry Lecture 2 continued
?Hydroboration
Jordan says
Now is there a way to hydrate an ALCOHOL with anti-markovnikov addition.
?
Jordan should have said
Now is there a way to hydrate an ALKENE with anti-markovnikov addition.
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