AAMC #10 PS Questions

[Jay2910]

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Hey everyone!

Couple of questions on PS.

Item 5:
The answer is D? The question is asking why the organic polymer is used. I chose A, because I thought the faster the precipitate forms the easier it is to get out of the solution.

What kind of background knowledge should I have to tackle this question? Why is breaking up a colloid helpful in removing the Cu and Zn from the solution? Isn't a colloid something like Jell-O? I thought having suspended particles makes them easier to remove?

Item 15:

So as an extended thought . . .does this mean that if I were to bring the image up really close to the convex lense . . .that my real and inverted image would turn smaller?

Also, I thought that the focal length convention for convex lens is negative? meaning its behind? why is it in the front here?

Question #47:

How do I even begin to solve this? I knew what each of the particles were ... . do you use intuition or Newton's law for this?
An electron is the lightest particle . .. so I thought that would surely travel 99% of light . .what's wrong with my reasoning?

Help would be awesome!

Thanks in advance!

 

[LoLCareerGoals]

How about you post actual problems if you want help?

 

[Jay2910]

Sure thing . .. .

5) What is the function of the organic polymer?

A)It catalyzes formation of metallic sulfides
B) It absorbs excess hydrochloric acid
C)it neutralizes excess ammonia
D)It breaks up colloidal suspension

#15) The figure below shows an arrow, pointing upward, located a distance p in front of a converging lens of focal length f. If p>f as in the figure, what kind of image of the arrow is formed by the lens?

http://i1072.photobucket.com/albums/w371/Goldeolde/Lens-1.jpg

47) Which particle would produce the largest anode signal when traversing a proportional chamber with an initial speed 99% that of light?

A) electron
B) a proton
C) a neutron
D) An alpha particle

 

[at3142]

#15 also stumped me. Any help would be wonderful.

 

[Narmerguy]

Sure thing . .. .

5) What is the function of the organic polymer?

A)It catalyzes formation of metallic sulfides
B) It absorbs excess hydrochloric acid
C)it neutralizes excess ammonia
D)It breaks up colloidal suspension

#15) The figure below shows an arrow, pointing upward, located a distance p in front of a converging lens of focal length f. If p>f as in the figure, what kind of image of the arrow is formed by the lens?

http://i1072.photobucket.com/albums/w371/Goldeolde/Lens-1.jpg

47) Which particle would produce the largest anode signal when traversing a proportional chamber with an initial speed 99% that of light?

A) electron
B) a proton
C) a neutron
D) An alpha particle

Questions #5 and #47 should have been solved from the passage. The passage from which #5 comes discusses that the particles aggregate together in little clumps and thus form a colloid so an organic polymer is added and the precipitate collected (or something like that, operating from memory)...from that you should infer its purpose is to solve the particle aggregation problem to obtain the precipitate.

For #47, the passage states that anode signals are dependent (proportional) to the kinetic energy of the charged particle. Thus, the question is basically asking which of those is a charged particle and would have the greatest kinetic energy if they all moved at the same speed (99% that of light). An alpha particle has an AMU of 4, a neutron has an AMU of 1 (it's also not charged, a proton has an AMU of 1, and electron has an AMU of 0. KE = (1/2)mv^2. Since they all have the same v, the one with the biggest m (mass) has the biggest kinetic energy.

#15 states that it is a converging lens. Converging lens form real images when the object is beyond the focal length, and virtual images when the object is within the focal length. Real images are always inverted. Thus, if the object arrow is pointing up, the real image formed would be pointing down. The focal length convention for convex mirrors vs convex lenses are different (opposite) and should not be mixed up.

 

[Jay2910]

Yeah I see can see it now . .thanks much!