AAMC CBT6 and 6R OFFICIAL Q&A

[Vihsadas]

This is the official Q&A thread for AAMC CBT6 and 6R.

Please post ONLY questions pertaining to AAMC CBT6 and 6R.
Out of respect for people who may not have completed the other exams, do not post questions or material from any other AAMC exam.

Please see this thread for the rules of order before you post.

Good luck on your MCAT!

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[ksmi117]

I am wondering if my CBT is messed up for this one

For passage II of BS, there is only one question showing. It is numbered 99 and then it jumps to 100 on the next passage

I had to pause my test, if anyone could give me a fast reply I would appreciate it

Not a mistake... just very odd...

 

[LaCasta]

Thanks ksmi,

That really threw me off.

Back to testing

 

[JaggerPlate]

Did anyone else think this test was terrible??? My verbal dropped from a 10/11 to a 7 ??????? WTF I've NEVER gotten that low of a score on a verbal, I don't even understand it. Also, why did the bio section have 1/2 the discretes about O-chem and then 3 full ochem passages??? God this test made no sense to me. I thought I bombed PS and it was my highest, and I don't know what happened on verbal because it felt fine and it was my lowest.

edit: realized I tried to switch my my verbal method, clearly didn't work ... going over it now. Still thought it was a bad test.

edit 2 (I'm sure no one cares): Verbal was normal except for the 'poem passage.' I missed every question!!! WOW. That's never happened to me.

 

[makingmd]

Hi All.

So I scoured the entire thread. Found a few mentions of this question as it was the sinculary question for one passage...weird. Anyway, why is the correct answer D when the graph clearly shows some (granted less) binding to both FN and Fg. Help me pls.

Item 99
In the presence of Drug C:
A)
IIb3 binds to Fg, and
51
binds to FN.
B)
IIb3 binds to Fg, and
51
does not bind to FN.
C)
IIb3 does not bind to Fg,
and
51 binds to FN.
D)
IIb3 does not bind to Fg,
and
51 does not bind to FN.

 

[SBR249]

This, I think, is a case where you can't judge by absolute numbers. You need to look at the relative proportions and data sets.

The passage merely mentions that they tried 3 different drugs to dissolve clots but didn't specify the concentration of the drug used or the mechanism of action of the drug. Thus, you can't be sure that they have added enough to completely inhibit binding. The only conclusion you can draw is that drug C has the effect of lowering the affinity of A5 cells for both FN and Fg during the experiment. In the context of the question, this logically leads to the conclusion that, at the molecular level, Drug C prevents binding for both types of integrins.

From a practical standpoint, I think, this also makes sense since you would want to merely minimize clotting of the blood to prevent heart attacks and strokes. You probably don't want there to be absolutely no clotting as that could be life-threatening.

 

[not so calm now]

One of the discretes got to me. It was a question about phenylhydrazine, and it required that you know the structure of this molecule and phenylhydrazone. Are these important molecules we're supposed to know? If so, are there any other obscure molecules you'd recommend memorizing the structure/functional groups of?

 

[SBR249]

You should know some of the commonly encountered organic reagents. In this case, hydrazine is a very common reagent in organic reactions (like the Wolff-Kishner) and this question is just testing whether you know it's basic structure and how to correlate nomenclature with structures of derivatives.

 

[Jhoa001]

I'm having a hard time understanding these two questions from Passage 7 BS. Can someone please explain? Thanks!

130) The passage suggests that the expression of disease genes probably is important in regulating normal celular physiology because:
A) Altered expression of disease genes leads to disease. (Correct)
B) The expression of disease genes leads to disease. (I chose this one.)

First off, the question seems a bit off to me. Why would expression of disease genes regulate cellular physiology? I understand how the altered expression of disease genes may lead to disease, but wouldn't the expression of disease genes also lead to disease?

132) The most likely shared feature of the clinical manifestations of NF1 is that they all:
C) Arise for one genetic defect ( I chose this one)
D) Arise from defects in gene expression. (Correct)

It states in the passage that "defects in a single gene cause the various clinical feasture that characterize this disease..." Therefore wouldn't C be correct?

 

[VanBrown]

I'm having a hard time understanding these two questions from Passage 7 BS. Can someone please explain? Thanks!

130) The passage suggests that the expression of disease genes probably is important in regulating normal celular physiology because:
A) Altered expression of disease genes leads to disease. (Correct)
B) The expression of disease genes leads to disease. (I chose this one.)

First off, the question seems a bit off to me. Why would expression of disease genes regulate cellular physiology? I understand how the altered expression of disease genes may lead to disease, but wouldn't the expression of disease genes also lead to disease?

132) The most likely shared feature of the clinical manifestations of NF1 is that they all:
C) Arise for one genetic defect ( I chose this one)
D) Arise from defects in gene expression. (Correct)

It states in the passage that "defects in a single gene cause the various clinical feasture that characterize this disease..." Therefore wouldn't C be correct?

The first one. There are no disease genes... no genes encode for a disease. Altered expression of normal genes lead to disease states. You can deduce that the altered expression of genes that are involved in normal physiology will cause disease states because if they were genes that were not expressed then there wouldn't' be much of a problem since the mutation in the gene isn't expressed in the first place.

The second one. Choice C says that all of the NF1 disease states are caused by a singular gene defect which isn't true. The passages says that the disease is caused b a defect in a single gene but that doesn't mean that that defect is the same in all patients.

 

[Jhoa001]

The first one. There are no disease genes... no genes encode for a disease. Altered expression of normal genes lead to disease states. You can deduce that the altered expression of genes that are involved in normal physiology will cause disease states because if they were genes that were not expressed then there wouldn't' be much of a problem since the mutation in the gene isn't expressed in the first place.

The second one. Choice C says that all of the NF1 disease states are caused by a singular gene defect which isn't true. The passages says that the disease is caused b a defect in a single gene but that doesn't mean that that defect is the same in all patients.

Thanks!

 

[Zona Pellucida]

Ugh this test sucked for me. Didn't finish PS. I usually average 10-13 on verbal and got a 10 here thanks to my dogs going on a barking rampage and the glacier passage. BS orgo killed me, I really hope there isn't much on my real MCAT.

Anyways..

#99. In the presence of Drug C:

A) aIIbB3 binds to Fg and a5B1 binds to FN
D) aIIbB3 does not bind to Fg and a5B1 does not bind to FN

The answer was D. I chose A.

At first I did have D because of the low percentage of cells bound as seen when Drug C is introduced. I then changed my answer to A because although the # of cells bound is severely reduced, THEY STILL BIND! (~10-15%). It is not zero percent. I switched my answer because I have gotten questions like this in the past wrong for not being precise with the answers, so I tried to here and got it wrong. : |

 

[MBigD011]

BS # 143

How much of the Glycolysis rxn and the rest of the respiration reactions do we need to know for the mcat?

I took Kaplan and went thru all the material. I know Glycolysis generally as:

GLu + 2 NAD+ -> 2 Pyrv + 2 NADH + 2 ATP

but should we know all the details? including ADP + Pi and for each part of respiration ETC/Krebs etc? or should we know the general for Aerobic and all of glycolysis.


BS #146

Bone components?? Bone is composed of Hydroxyapatite which has PO4 Ca & OH. damn what else do we need to know about bones. Seems like my kaplan review is lacking some details.

 

[fluff]

Could someone please explain #27 on PS?

What is the effective spring constant of the system of two springs shown in figure 1?

A) K
B) 2K
C) K/2
D) 0

how do you know to add the two spring constants?? isn't the stiffness of the springs the same whether you have one or two?

 

[orrghead16]

BS # 143

How much of the Glycolysis rxn and the rest of the respiration reactions do we need to know for the mcat?

I took Kaplan and went thru all the material. I know Glycolysis generally as:

GLu + 2 NAD+ -> 2 Pyrv + 2 NADH + 2 ATP

but should we know all the details? including ADP + Pi and for each part of respiration ETC/Krebs etc? or should we know the general for Aerobic and all of glycolysis.

You don't need to know much more than this, I don't think. But, you do need to understand the fundamentals of how glycolysis works. I.e. you need to know that 2 ATP are required in the preparation phase of glycolysis. You should also probably know that 4 ATP are actually produced, but only 2 NET. As for knowing that it requires ADP and Pi, this is basically common sense. You can't just pull ATP from glucose, you are just using glucose's electrons to reduce electron carriers and substrate level phosphorylation.

 

[orrghead16]

Could someone please explain #27 on PS?

What is the effective spring constant of the system of two springs shown in figure 1?

A) K
B) 2K
C) K/2
D) 0

how do you know to add the two spring constants?? isn't the stiffness of the springs the same whether you have one or two?

We need Keff

Intuitively, both springs are the same. Both springs are causing the mass to be at rest at equilibrium. BOTH springs will resist motion if we try and move the mass, hence both are imparting a force in the same direction (resisting motion) on the mass. The stiffness is the exact same in both springs (BUT THE OVERALL FORCE IS NOT!), but the key to this problem is to think how each spring imparts a force on the mass, and then use that to solve for Keff. Thinking: if you tried to stretch a spring, (I.e. moving the mass to the L with just the R spring attached), that spring would want to pull you back (Force to the R). On the other hand, just have the L spring attached, and try to push the mass to the L, the L spring is going to push you back (2nd force to the R) --> The forces are additive & in the same direction.

Ftot = (Right spring K)*x + (Left spring K)*(x)
Ftot= Kx+Kx = 2Kx = (Keff)*x.

Keff = 2K

Alternatively, the forces would still be additive if the K's were different and the springs had different stiffness. In this case, Keff would be (K1 + k2).

 

[Aggro]

Passage II, Question 4.

"The example of the 'superb engineering of a gull' is most relevant to the author's assertation that a perfect matching organism to its environment:

C. Is an illusion because species are constantly evolving. <-- my answer
D. Can be used to support creationism as well as the evolutionary position. <-- wrong answer

Paragraph 4: "But you cannot demonstrate evolution with perfection because perfection need not have a history."

Ergo, according to the author, the super engineering CANNOT be used to demonstrate evolution. Right? What the hell? This is one of two questions I missed and I don't get it.

 

[dray5150]

Hey Im having trouble with question 22 on BS
Which of the following will NOT influence the oxygenation of blood in the pulmonary circulation?
a.rate and depth of breathing
b.Hemoglobin concentration of the blood
c. Blood pressure in the pulmonary artery
d. Surface area of the aveoli

I limited out d and b immediately and choose A. My reasoning is why wouldn't Blood pressure not affect the oxygenation of blood? Would'nt it allow for less gas exchange if blood pressure was high moving through the pulmonary artery? In retrospect I see why rate and depth of breathing would be an obvious influence... still confused though.

 

[Aggro]

My reasoning for why blood pressure in the pulmonary artery doesn't matter is that blood pressure doesn't affect the concentration of oxygen and carbon dioxide.

 

[ronaldo23]

question 50 on the PS... it says

An electrochemical cell is designed to produce pure copper from CuSO4. An increase in which of the following cell conditions will most effectively increase the rate at which pure copper is produced?

The answer was you increase the current of electricity. The answer explanation then goes on about how increasing the current is how an electrolytic cell is driven. But aren't electrochemical cells different from electrolytic cells; is this a typo?

 

[ronaldo23]

bump

 

[boaz]

Regarding item 35 (CBT):

The perturbing force resulting from sublimation in the dirty-snowball model is accounted for directly by which of Newton’s laws?


A) The law of inertia (Newton’s 1st law)


B) The law relating force, mass, and acceleration (Newton’s 2nd law)

C) The law relating action and reaction (Newton’s 3rd law)

EXPLANATION: "The perturbing force of gas sublimation pushes against the comet’s solids as the gases evaporate. This is an example of Newton’s third law, action (gas released) and reaction (push against the frozen solid) forces. Answer C is the best choice to explain for the perturbing force."

D) The law of gravitation (Newton’s inverse-square law)

​

How is this a case of action-reaction? Newton's 3rd Law states that if A exerts a force F on B, then B will exert force -F on A. In this case, there is definitely a reaction force, but what does that have to do with the perturbing force? I'm assuming this "perturbing force" causes acceleration which results in the orbit deviations described in the passage. The newly created gas (as a result of an input of force by Sun's radiation) simply exerts a pressure (F/A) on the solid cometary nucleus. This force accelerates the mass of the nucleus.

Anyone? Any physicists?

 

[boaz]

Come on, you guys are making this sound like such a brilliant question. Are y'all stumped or just have your noses buried in the books?

 

[starbaduk]

Regarding item 35 (CBT):

The perturbing force resulting from sublimation in the dirty-snowball model is accounted for directly by which of Newton’s laws?


A) The law of inertia (Newton’s 1st law)


B) The law relating force, mass, and acceleration (Newton’s 2nd law)

C) The law relating action and reaction (Newton’s 3rd law)

EXPLANATION: "The perturbing force of gas sublimation pushes against the comet’s solids as the gases evaporate. This is an example of Newton’s third law, action (gas released) and reaction (push against the frozen solid) forces. Answer C is the best choice to explain for the perturbing force."

D) The law of gravitation (Newton’s inverse-square law)

​

How is this a case of action-reaction? Newton's 3rd Law states that if A exerts a force F on B, then B will exert force -F on A. In this case, there is definitely a reaction force, but what does that have to do with the perturbing force? I'm assuming this "perturbing force" causes acceleration which results in the orbit deviations described in the passage. The newly created gas (as a result of an input of force by Sun's radiation) simply exerts a pressure (F/A) on the solid cometary nucleus. This force accelerates the mass of the nucleus.

Anyone? Any physicists?

Comet applies force on the environment by way of sublimation. Environment, in turn, applies force on the comet.

That's what I thought anyway. It seems similar to the uncorked air baloon moving through the air, as it deflates.

 

[starbaduk]

question 50 on the PS... it says

An electrochemical cell is designed to produce pure copper from CuSO4. An increase in which of the following cell conditions will most effectively increase the rate at which pure copper is produced?

The answer was you increase the current of electricity. The answer explanation then goes on about how increasing the current is how an electrolytic cell is driven. But aren't electrochemical cells different from electrolytic cells; is this a typo?

I assumed electrochemical cell is electrolytic cell. Are they different?

 

[pandoraaj009]

Dust, being a solid, has a surface. As such, it can reflect. If you think about a beam of light in a dark room you see it illuminating all of the dust particles hovering in the air, but it doesn't illuminate the nitrogen gas or oxygen gas, etc...

Basically, it just comes down to needing a surface to have a reflection.

think of the tyndall effect!

 

[johndoe3344]

I'm referring to the question about proton NMR in passage XI.

From what I understand, -O should be an electron donating group, not an electron withdrawing group. Why is the peak from the 3 protons shifted downfield and not upfield?

 

[letaps]

Hey,

Why isn't the answer B, because according to the equation V = iR, if voltage increase, the current increases.

Electric power for transmission over long distances is “stepped up” to a very high voltage in order:

A) to produce currents of higher density.

B) to produce higher currents in the transmission wires.

C) to make less insulation necessary.

D) to cut down the heat loss in the transmission wires.
Power transmitted to a load at the user’s end of an electrical line is the product of the current I times the voltage V at the user’s end. The power company has the option of using a low voltage or a high voltage for a given amount of power delivered. Using Ohm’s law (I = V/R), the power delivered can also be written as P = V2/R. The power lost in the transmission line is I2R. Since the resistance R is fixed by the material and dimensions of the line, we see that using a high voltage at a lower current maximizes the power to the user and minimizes the heat loss in the transmission line, choice D.

 

[jjoo915]

I also struggled with this question while trying to solve it during the test, but the answer key made sense afterwards. The tricky part to have realized was that power loss in the wire due to resistance varies with I, as P=(I^2)R expresses, while the power delivered is expressed in V as P=(V^2)/R states. The company wants to deliver as much power as possible with minimal loss due to resistance, but the company can vary the combination of voltage and current. From P=IV, using a high V results in a low I for a given P. So the combination of high V and low I will maximize power delivered while minimizing power lost.

I agree this question was tricky to think through "on the spot" unless you just happened to remember from your physics class that power is dissipated across resistors as current physically flows through (like lightbulbs).

 

[Doodl3s]

WOW, yes, I agree this question is actually miserable lol, and i consider physics one of my best subjects. However, after literally a good 5 minutes of re-reading this I finally get why and it all comes down to the wording...

It says Electric power for transmission is stepped up to a high voltage. Meaning they changed the Voltage of the power. This means you should focus more on the fact that P=VI... so a higher voltage at the same power means lower current. That explains THEIR answer...

BUT i have a question of my own. V^2/R and I^2R are both different equations FOR power... so how is one what is lost and one what is delivered when they should both equal the same number?

EDIT: was this a passage question that happens to tell you that v2/R is whats delivered, and I2R is whats lost? that may explain things.

 

[letaps]

it was a stand alone question....i still don't understand why the answer isn't why the answer isn't B, how do you know to use the equation P = iV and not V = iR?

 

[Doodl3s]

If "Power" was stepped up to a "high voltage", and (you have to assume the overall power to the person hasn't changed) then P=VI... V goes up, I goes down

 

[letaps]

yes, but why can't you use V = iR, which would mean when voltage increases, current increases...

 

[jjoo915]

yes, but why can't you use V = iR, which would mean when voltage increases, current increases...

You should think of V=IR in the context of how it applies to circuits. This equation tells you that when you have a fixed R, the amount of current flowing depends on how much voltage is applied. So while it's true that I increases as V increases, you need to have realized that power loss due to resistance in a wire increases as I increases. So the company would want to avoid sending high currents through long distance wires with high resistance, making choice B unlikely.

 

[IncuSpy]

Looking at this problem made me immediately remember what my physics teacher said about this stuff.

"V is increased to prevent heat dissipation (from greater R). Purely conceptual, dont bother with the math"

but to paint the picture. Dont look at the equation as V=iR and that I and R are variable. It is R = V/I. R is CONSTANT because it is a quality of the wire - it does not change. Therefore if R is const. in V=IR, then I increases more than the other variables in order to keep R const.

So in R=V/I if I gets much bigger R will remain low.

Or you can just remember "power lines have a high V to keep R low, less heat dissipated."

 

[capn jazz]

I am really blanking on this. PS Q 26. A ball is thrown up vertically with velocity v from earth, and returns in time t. If g were reduced to g/6, then t would....

It's increase by a factor of 6. I don't get why.

They say the total time t is t = 2v/g. Where does this come from?? Someone want to help? I'm sure it's totally simple but I'm not seeing why t isn't squared.

 

[Dr Gerrard]

I am really blanking on this. PS Q 26. A ball is thrown up vertically with velocity v from earth, and returns in time t. If g were reduced to g/6, then t would....

It's increase by a factor of 6. I don't get why.

They say the total time t is t = 2v/g. Where does this come from?? Someone want to help? I'm sure it's totally simple but I'm not seeing why t isn't squared.

v = vo + at

vo is the same for both. v is 0 for both (velocity at top is 0)

0 = vo + at

acceleration is negative.

at = vo

t = vo/g

This is just the time it takes to get to the top. The overall trip is this times 2.

t = 2vo/g

 

[capn jazz]

Thank you! I swear, I don't know why kinematics equations slip out of my brain so easily.

 

[ksmi117]

Please keep any discussion of questions from the AAMC tests to the designated AAMC test threads. Many people read these posts and if they see a question from an AAMC before they take it, it could skew their practice scores.

Merging with the AAMC 6 thread.

 

[Dr Feelgood]

Hi All.

So I scoured the entire thread. Found a few mentions of this question as it was the sinculary question for one passage...weird. Anyway, why is the correct answer D when the graph clearly shows some (granted less) binding to both FN and Fg. Help me pls.

Item 99
In the presence of Drug C:
A)
IIb3 binds to Fg, and
51
binds to FN.
B)
IIb3 binds to Fg, and
51
does not bind to FN.
C)
IIb3 does not bind to Fg,
and
51 binds to FN.
D)
IIb3 does not bind to Fg,
and
51 does not bind to FN.

it says in the passage drug X binds to this, then drug Y binds to this. Then you have to look at the graphs and deduce answer D.

 

[Dr Feelgood]

What was this test?

I did well - 12/9/12 but my verbal score has never been below a 10 and was averaging around 11.

what was this test?

are they just getting harder?

 

[milindian]

"Which of the following changes would NOT interfere with the repeated transmission of an impulse at the vertebrate nueromuscular junction?"
a) Addition of a cholinesterase blocker
b) Addition of a toxin that blocks the release of acetylcholine
c) An increase in acetylcholine receptor sites on the motor end plate
d) Addition of a substance that binds to acetylcholine receptor sites

So I chose answer choice C (which is the correct one), but I don't quite understand why it cant be answer choice A. The Kaplan/AAMC explanations aren't really sufficient in my opinion. A cholinesterase blocker would mean that less acetylcholine is degraded and so its concentration in the neuromuscular junction would build up. With an increased NTMT concentration I would imagine that the chance of it synapsing on an acetylcholine receptor site would be higher and this would consequently happen at a higher rate. Thus, an impulse is more likely to be transmitted across the synapse and so will "not interfere with repeated transmission". Answer choice C also works because it would also increase the likelihood of a NTMT binding to a receptor site and lead to transmission of the impulse. B and D are certainly wrong because they are the opposite of what is needed. SOOOO can someone please explain why answer choice A MUST be eliminated?

 

[milindian]

got another one (sorry just took this today...)

i understand why the Z conformation is possible given the data, but what excludes the A conformation... doesn't the observed helical twist fall well within its range?

Yeah! I had the same question. Again, the question basically gives a table that has three conformations based on average helical twists (in degrees) between adjacent nucleotide pairs. The question then states that there are 12 nucleotides in in every full 360deg helical turn. 360/12 = 30deg between adjacent nucleotides. Z conformation (29.9 +/- 1) works, BUT A conformation (33.1 +/- 6) should also work! There is no option that has both A and Z as the correct conformations, but its seems that they should. Anybody have a reason why A can be excluded? Or is this a mistake?

 

[G1SG2]

Question 50 from PS:

An electrochemical cell is designed to produce pure copper from CuSO4. An increase in which of the following cell conditions will most effectively increase the rate at which pure copper is produced?

A. The concentration of SO42+
B. The current of electricity
C. The size of the cathode
D. The size of the anode

This question confuses me. It says "an electrochemical cell". Can't that be either a galvanic cell OR an electrolytic cell? Or is an "electochemical cell" strictly an electrolytic cell? From my understanding, it can be either galvanic or electrolytic. How was I supposed to tell just based on the wording of the question? Thanks.

 

[thebillsfan]

Everyone says this is a ridiculous question...I don't think so. I think what people need to understand is that POWER TRANSMITTED (IV) through a power line is not that same thing as POWER LOSS (ie, I^2R). The two powers are NOT equivalent, so just b/c the Power in P=IV remains the same, that doesnt mean the power loss in I^2R has to remain the same.

 

[G1SG2]

Question 50 from PS:

An electrochemical cell is designed to produce pure copper from CuSO4. An increase in which of the following cell conditions will most effectively increase the rate at which pure copper is produced?

A. The concentration of SO42+
B. The current of electricity
C. The size of the cathode
D. The size of the anode

This question confuses me. It says "an electrochemical cell". Can't that be either a galvanic cell OR an electrolytic cell? Or is an "electochemical cell" strictly an electrolytic cell? From my understanding, it can be either galvanic or electrolytic. How was I supposed to tell just based on the wording of the question? Thanks.

bump

 

[thebillsfan]

Pookiez...

When I did this question, I immediately thought electrolytic cell, but I shouldn't have because electrochemica cell can refer to either. Now, think about the ? this way. Obviously A is out because it's a ridiculous choice. I didn't think too much about either C or D because if one was true, the other certainly had to be true, so they're both out. But back to your real question...increasing the current will incresae the rate at which copper is produced whether its a galvanic or electrolytic, and so you dont have to know which one it is. The difference, which is hard to explain, and at the risk of confusing you even more (and making myself look like a fool), is that in an electrolytic cell, actively increasing electricity (amping up the power of the generator or whatever is driving it) will increase the rate of copper formation, since youre pumping more electrons to the cathode (cathode is the site of copper reduction). Alternatively, in a galvanic cell, you aren't actively increasing the electricity, but if the current were somehow to magically increase (the question is not asking you HOW its increased, just that the current is increased), then obviously copper production would increase b/c more ions would be forced to the cathode.

So, to try and sum up, the point isn't what type of cell it is. Whether you have a stronger generator or a larger concentration gradient (electrolytic and concentration cells, respectively), the current will increase and in either situation the copper production will increase.

Was that useful?

 

[G1SG2]

Pookiez...

When I did this question, I immediately thought electrolytic cell, but I shouldn't have because electrochemica cell can refer to either. Now, think about the ? this way. Obviously A is out because it's a ridiculous choice. I didn't think too much about either C or D because if one was true, the other certainly had to be true, so they're both out. But back to your real question...increasing the current will incresae the rate at which copper is produced whether its a galvanic or electrolytic, and so you dont have to know which one it is. The difference, which is hard to explain, and at the risk of confusing you even more (and making myself look like a fool), is that in an electrolytic cell, actively increasing electricity (amping up the power of the generator or whatever is driving it) will increase the rate of copper formation, since youre pumping more electrons to the cathode (cathode is the site of copper reduction). Alternatively, in a galvanic cell, you aren't actively increasing the electricity, but if the current were somehow to magically increase (the question is not asking you HOW its increased, just that the current is increased), then obviously copper production would increase b/c more ions would be forced to the cathode.

So, to try and sum up, the point isn't what type of cell it is. Whether you have a stronger generator or a larger concentration gradient (electrolytic and concentration cells, respectively), the current will increase and in either situation the copper production will increase.

Was that useful?

Useful, indeed! Very nice explanation. Thanks!!

 

[G1SG2]

How did you guys find the "Brand Prop" passage in the paper version of the test (I believe it was passage 5 in 6R)??? I TOTALLY bombed it. First of all, it had like 10 questions...I hope the current MCAT doesn't have verbal passages with ten questions?! The passage was fairly simple, I thought I was going to do alright on it but damn, I completely got slammed. I got a 10 in verbal, in the CBT version so that was quite a shock. My test is two weeks away. This is not cool. Is it just me, or was that passage tricky?

 

[G1SG2]

Edit: nvm

 

[G1SG2]

"The student determines the Ksp of lead (II) bromide to be 4.6 x 10^-6 at 25 degrees celsius."

The question is:

Will lead (II) bromide precipitate if the student mixes 0.001 M solution Pb2+ (aq) with 0.00005 M solution of Br- (aq)?

Answer: No,because the Ksp exceeds the ion product. The ion product is [Pb2+][Br]^2=(0.0001)(0.00005)^2=2.5 x 10^-13. The passage states that the Ksp for lead (II) bromide is 4.6 x 10^-6.

However, my question is, am I to assume that the student added those ions in a solution that was already saturated? And that's why we multiply the concentration of the ions to get the "ion product" since they were on the product side?

PbBr2 (s)--> Pb2+ + 2Br-

Is that how it is?