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For those of you who have used examkrackers simulated exam 1d, what did you think of it? does it resemble the real thing? is the scale and scoring indicative of the real mcat?
Originally posted by danwsu
Are the questions as hard as the ones in the lesson books?
Originally posted by twesting2173
i wondered if either of you (or anyone else who might be able to) woudl be willing ot send me their old EK tests. I honestly cant afford the 20 buck per exam, but hoped you might be willing ot send me your left overs when you're done. i can pay you 5 or 10 buck.....please? thanks so much, i appreciate it.
Originally posted by Mr. Z:
You are right about their vapor pressures being different, that arises from the colligative properties of the solute in beaker B. But, there is no way that 100% of the solvent in beaker A could end up in beaker B. For the system to come to equilibrium the vapors from beaker A would first have to saturate the entire apparatus, once there is saturation then an equilibrium process could begin and solvent A would then start fill beaker B. But, there would always be that fraction of solvent A that was has to fill the apparatus and that fraction doesn't make it into beaker B. So based on that i thought the best answer would be C... beaker B contains 90% of all solvent.
My explanation maybe a little confusing, hopefully it makes sense. what do you think?
Originally posted by JOrsay
The system moves toward equilibrium. Solvent molecules escape from a pure solvent faster than from a the same solvent with nonvolatile solute. The atmosphere in the enclosed container struggles to reach equilibrium with both cups. There is a net movement of solvent into the solution with nonvolatile solute.
Vapor pressure is a colligative property. The vapor pressure is independent of the amount of solvent, so the vapor pressure of the pure solvent doesn't change. The solution will always have a lower vapor pressure because it will always contain some concentration of solute. So if any of the solvent transfers to the solution, all of it must over time. Whether solvent transfers to the solution doesn't depend upon the amount of pure solvent.
The pure solvent will completely evaporate over time.
The explanation to this question posted just above this post would indicate that a puddle of water could never evaporate unless humidity were zero because there would always be some vapor pressure over the water. Although I have never taught chemistry for Berkeley Review, I would have to disagree with this supposition.
Originally posted by JOrsay:
The system moves toward equilibrium. Solvent molecules escape from a pure solvent faster than from a the same solvent with nonvolatile solute. The atmosphere in the enclosed container struggles to reach equilibrium with both cups. There is a net movement of solvent into the solution with nonvolatile solute.
Vapor pressure is a colligative property. The vapor pressure is independent of the amount of solvent, so the vapor pressure of the pure solvent doesn't change. The solution will always have a lower vapor pressure because it will always contain some concentration of solute. So if any of the solvent transfers to the solution, all of it must over time. Whether solvent transfers to the solution doesn't depend upon the amount of pure solvent.
The pure solvent will completely evaporate over time.
The explanation to this question posted just above this post would indicate that a puddle of water could never evaporate unless humidity were zero because there would always be some vapor pressure over the water. Although I have never taught chemistry for Berkeley Review, I would have to disagree with this supposition.
Originally posted by JOrsay:
Your suggestion that a solvent CANNOT evaporate when there is solvent vapor above is incorrect.
Originally posted by JOrsay:
I suppose that you feel mentioning Clausius-Clapeyron lends credence to your argument. This would only be true if you were using the equation correctly. The equation is simply irrelevant to the discussion.
Originally posted by JOrsay:
I have noticed that this is not the first time that you have freely offered advice where you are not qualified to do so. For instance, you suggested Feynman as "a bible for common physics" when studying for the MCAT. Obviously you have never opened a book by Feynman. It is physics based upon differential calculus. Hardly a bible for common physics. One who can read Feynman and understand him is already knowledgable in both math and physics and doesn't need help to understand MCAT physics.
Originally posted by JOrsay:
Your past posts suggest that you believe that you are an expert at economics, MCAT, chemistry, and Examkrackers MCAT books. I am more than a little skeptical.
Originally posted by JOrsay:
I My concern is not for your misguided enthusiasm to assist others despite being unqualified to do so. My concern is for your adhominem attacks against Examkrackers while blatantly promoting Berkeley Review materials.
Originally posted by JOrsay:
However, if you insist on misinforming students about our material, I intend to correct your errors.
Originally posted by JOrsay:
Mudd, Feynman is not a 'common sense' physics book, the CC equation is still not useful in explaining this problem, I still believe that you are an undercover salesman for Berkeley, and your economic theory was silly. However, I did misread your post and my 'attack', in that regard, was unwarranted.