Fullerenes

[susan.meng]

Although fullerenes - spherical molecules made entirely of carbon - were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Which of the following, if true, most seriously undermine the argument?

a) Confirming that the shungite genuinely contained fullerenes took careful experimentation

b) Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft

c) The mineral shungnite itself contains large amount of carbon, from which fullerenes apparently formed

d) The naturally occurring fullerenes are arranged in a previously unknown crystalline structure

e) Shungite itself is only formed under distinctive conditions

Please explain why D is correct.

[jayachandran.b]

D undermines the argument by attacking the premise by suggesting that naturally occurring fullerene and synthetic fullerene differ in their structure. Since the objects of comparison are not similar, the comparison between the conditions these were formed does not stand.

By elimination method..

A) the effort which took to confirm fullerene presence in shungite is irrelevant to the argument. What matters is whether shungite contains fullerene or not.

B) This one is close. I almost fell for it. It seems to offer an alternate explanation for the formation of fullerene. But what should be considered is, even if fullerene is formed in outer space does that change anything if it is also formed in earth? No, it does not.

C) This one provides more evidence to the argument and thus is strengthening the argument.

E) This is the premise itself.

Hope it helps.

[susan.meng]

thanks, great explanation

[RonPurewal]

yeah, that's an excellent explanation up there.

when you look to WEAKEN AN ARGUMENT, what you normally do is UNDERMINE CONNECTIONS OR ASSUMPTIONS that are made in the argument.

in this problem, the argument just assumes that the conditions under which fullerenes were made in the lab are identical to the conditions under which they grow in nature.

we can't directly undermine that connection, since we don't have any actual direct data about the conditions under which fullerenes grow in nature. HOWEVER, if we can show that the fullerenes that were made in the lab are actually DIFFERENT from the fullerenes that grow in nature, then this connection will be severed. IE if we're actually talking about two completely different kinds of fullerenes, then any information about the conditions precipitating the growth of one kind can't be taken to apply to the growth of the other kind.

that's what happens in choice (d), which tells us that the natural fullerenes aren't the same chemical as the lab-made ones.

[monira.linda]

Ron pls help..

d) The naturally occurring fullerenes are arranged in a previously unknown crystalline structur

I thought it was previously unknown and now known. So somehow is helping.


e) Shungite itself is only formed under distinctive conditions

I thought Since laboratory synthesis of fullerenes requires distinctive conditions and Shungite itself is only formed under distinctive conditions...so these two are two different distinctive condition and thus we cant compare.

Pls help me what am I missing?

[RonPurewal]

Ron pls help..

d) The naturally occurring fullerenes are arranged in a previously unknown crystalline structur

I thought it was previously unknown and now known. So somehow is helping.

in the given context, the only reasonable interpretation of "previously unknown" is that the crystalline structure was unknown up until this particular discovery.
thus, it can be inferred that this crystalline structure is not the same as that of other, previously discovered fullerenes.


[/quote]e) Shungite itself is only formed under distinctive conditions

I thought Since laboratory synthesis of fullerenes requires distinctive conditions and Shungite itself is only formed under distinctive conditions...so these two are two different distinctive condition and thus we cant compare.[/quote]

there is nothing here from which one might infer that the two sets of "distinctive conditions" are necessarily different from each other.

[kkunal86.malhotra]

Hi Ron,

Please help , I have my GMAT around the corner.

I am still confused with option (b)
It says
"Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft"

The statement might as well mean that the distinctive conditions of temperature and pressure will help in evaluating the state in the space (and not the state of the Earth's crust). This will weaken the statement.

[RonPurewal]

Hi Ron,

Please help , I have my GMAT around the corner.

I am still confused with option (b)
It says
"Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft"

The statement might as well mean that the distinctive conditions of temperature and pressure will help in evaluating the state in the space (and not the state of the Earth's crust). This will weaken the statement.

no.
this statement just says that some (other) fullerenes were found in outer space.
so, sure, the conditions of those fullerenes might suggest things about outer space ... but those conditions would have nothing whatsoever to do with the (completely different) fullerenes found "in nature", i.e., on earth.