GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 17 Feb 2019, 18:56

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Algebra Webinar

February 17, 2019

February 17, 2019

07:00 AM PST

09:00 AM PST

Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
• ### Valentine's day SALE is on! 25% off.

February 18, 2019

February 18, 2019

10:00 PM PST

11:00 PM PST

We don’t care what your relationship status this year - we love you just the way you are. AND we want you to crush the GMAT!

# Spectroscopic analysis has revealed the existence of frozen nitrogen

Author Message
TAGS:

### Hide Tags

VP
Joined: 26 Apr 2004
Posts: 1135
Location: Taiwan
Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

Updated on: 09 Oct 2018, 05:49
3
31
00:00

Difficulty:

95% (hard)

Question Stats:

44% (02:29) correct 56% (02:34) wrong based on 1156 sessions

### HideShow timer Statistics

Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Pluto's atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.

The astronomers' argument relies on which one of the following assumptions?

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.

Originally posted by chunjuwu on 14 Mar 2005, 00:39.
Last edited by Bunuel on 09 Oct 2018, 05:49, edited 1 time in total.
Renamed the topic and edited the question.
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 4770
Location: Singapore
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 Mar 2005, 20:52
8
1
Here's a diagramming of the passage I did.

1) Spectroscopic analysis revealed existence of frozen nitrogen, methane and carbon monoxide on surface of pluto
2) Such ice have tendency to vaporize, producing an atmosphere
3) Proportion of gas in atmosphere depends directly on how readily corresponding ice vaporize
4)Astronomers concluded that components of Pluto's atmosphere are nitrogen, Carbon monixide and methane in decreasing abundance.

1, 2 and 3 are premises --> All facts
4 is a conclusion --> A claim (made by the astronomers)

In decreasing abundance means in Pluto's atmosphere, there is more nitrogen, than carbon monxide, and more carbon monxide than methane. It's talking about the gases that make up the atmosphere, and telling us which gas is higher in proportion.

Based on premise 3, if the conclusion is true, nitrogen vaporizes the fastest, followed by carbon monoxide, and methane.

Now we'll look at answer choice (C).

"There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. "

In order for the astronomer's claim that nitrogen is highest in proportion followed by carbon monoxide then methane, we need a statement that tells us that the proportion is indeed in this order.

(C) does that perfectly. It tells us there is no frozen substance (e.g. frozen oxygen) that vaporizes faster than methane but slower tan carbon monoxide
##### General Discussion
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 4770
Location: Singapore
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

14 Mar 2005, 08:55
1
(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.
- Out. Does not tells us there is more frozen nitrogen than frozen carbon monoxide/methane

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.
- Out of scope

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.
- This one explains why there is a decreasing abundance from nitrogen to carbon monxide to methane.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.
- Does not explain the abundance. We're already told the ice vaporize to produce an atmosphere, so this choice does nothign more than to give a redundant premise

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.
- out of scope

I'll go with C
VP
Joined: 26 Apr 2004
Posts: 1135
Location: Taiwan
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 Mar 2005, 23:24
ywilfred wrote:
Here's a diagramming of the passage I did.

1) Spectroscopic analysis revealed existence of frozen nitrogen, methane and carbon monoxide on surface of pluto
2) Such ice have tendency to vaporize, producing an atmosphere
3) Proportion of gas in atmosphere depends directly on how readily corresponding ice vaporize
4)Astronomers concluded that components of Pluto's atmosphere are nitrogen, Carbon monixide and methane in decreasing abundance.

1, 2 and 3 are premises --> All facts
4 is a conclusion --> A claim (made by the astronomers)

In decreasing abundance means in Pluto's atmosphere, there is more nitrogen, than carbon monxide, and more carbon monxide than methane. It's talking about the gases that make up the atmosphere, and telling us which gas is higher in proportion.

Based on premise 3, if the conclusion is true, nitrogen vaporizes the fastest, followed by carbon monoxide, and methane.

Now we'll look at answer choice (C).

"There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. "

Hello, look at red part.
nitrogen vaporizes the fastest, followed by carbon monoxide, and methane

There is no frozen substance on the surface of Pluto that vaporizes more readily than methane Is it not carbon monoxide and nitrogen?

...but less readily than carbon monoxide
Is it not methane ?

Thanks
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 4770
Location: Singapore
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

16 Mar 2005, 02:43
5
1
chunjuwu wrote:
ywilfred wrote:
Here's a diagramming of the passage I did.

1) Spectroscopic analysis revealed existence of frozen nitrogen, methane and carbon monoxide on surface of pluto
2) Such ice have tendency to vaporize, producing an atmosphere
3) Proportion of gas in atmosphere depends directly on how readily corresponding ice vaporize
4)Astronomers concluded that components of Pluto's atmosphere are nitrogen, Carbon monixide and methane in decreasing abundance.

1, 2 and 3 are premises --> All facts
4 is a conclusion --> A claim (made by the astronomers)

In decreasing abundance means in Pluto's atmosphere, there is more nitrogen, than carbon monxide, and more carbon monxide than methane. It's talking about the gases that make up the atmosphere, and telling us which gas is higher in proportion.

Based on premise 3, if the conclusion is true, nitrogen vaporizes the fastest, followed by carbon monoxide, and methane.

Now we'll look at answer choice (C).

"There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. "

Hello, look at red part.
nitrogen vaporizes the fastest, followed by carbon monoxide, and methane

There is no frozen substance on the surface of Pluto that vaporizes more readily than methane Is it not carbon monoxide and nitrogen?

...but less readily than carbon monoxide
Is it not methane ?

Thanks

Hi Chunjuwu, let me give an example illustrating what I meant. We know that the three gases, nitrogen, carbon monoxide and methane must go in this order from most to least: Nitrogen -> Carbon Monoxide -> Methane.

Now if there's another substance, say frozen oxygen that vaporiese faster than methan but slower than Carbon Monoxide, we will get:
Nitrogen -> Carbon Monoxide -> Oxygen -> Methan. This is exactly the situation C helps us to avoid getting into. It says no other substance, vaporizes faster than Methane, and slower than Carbon monoxide. This means we will never end up in this situation:

Nitrogen -> Carbon Monoxide -> Other Subsance -> Methane.

And if we can never get into the situation above, the conclusion will hold.

Hope what I explained is clear for you. Let me know if you need more
SVP
Joined: 03 Jan 2005
Posts: 2097
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

16 Mar 2005, 09:24
1
1
This question puzzles me too. The question stem could lead to many good choices but the choices given are not exactly what you'd expect. Anyways here's what I think.

Fact: There are frozen N2, Methane, and CO on the surface of Pluto.
Fact: Such ice tend to vaporize and produce an atmosphere.
Fact: The proportion of any gas depends on how readily the corresponding ice vaporizes.
Conclusion: The components of Pluto's atmosphere are N2, CO, and methane, with N2>CO>Methane.

The obviouse assumption I can see from the passage is that N2 is more readily vaporized CO follows, and Methane is least readily vaporized.

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.
This almost feels like the only possible correct answer that they want to test you. However it should have been "there is no less frozen nitrogen than carbon monoxide or methane", instead of "no more... than". The way it is formulated now, it doesn't seem to be an assumption that the scientists need to make. Even if there is more frozen N2 than the others, this would make the N2 gas more abundant than the others, and will not overthrow the conclusion.

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.
This is a bit out of scope I think.

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.
This looks like a trap. What one is supposed to think is that "well what if there's some other frozen gas that is not discovered whose readiness to vaporize is between Methane and CO?" However, I think the way the conclusion is spelled out has ruled out this possibility. The conclusion says "The components of Pluto's atmosphere are" this this and that. In other words, it didn't say these three are in the atmosphere. The subtle difference to me is that the second way you can say other things may also be in the atmosphere, but the first way you are sure the only components are these three.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.
As I said before, the problem with this is "only if".

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.
I tried to see if there's something here. But it looked out of scope to me.

Therefore among the five choices C looks like the closest to me.
Retired Moderator
Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL
Joined: 04 Oct 2009
Posts: 1135
Location: Peru
Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)
WE 1: Economic research
WE 2: Banking
WE 3: Government: Foreign Trade and SMEs
Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

10 May 2012, 08:44
2
13
Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Pluto’s atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.

The astronomers’ argument relies on which one of the following assumptions?

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.
(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.
(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.
(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.
(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed

Source : LSAT PrepTest 21

OA is C
I agree with the OA. However, I have a doubt with choice A. If we use the negation technique, and we assume that "there is MORE frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane". The conclusion could be weakened. Let me explain:

The argument says that the the RATE OF EVAPORIZATION of each ice (readiness) determines the proportion of each gas in the atmosphere. However, let's suppose that Nitrongen (the most abundant in atmosphere) has the lowest rate of evaporation but it is the most abundant as ice on the surface ( my negation technique). Nitrogen would be the most abundant in atmosphere not by the rate of evaporization, but by the amount of nitrogen on the surphace. The reasoning of the author would be weakened

Thanks!
_________________

"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can."

My Integrated Reasoning Logbook / Diary: http://gmatclub.com/forum/my-ir-logbook-diary-133264.html

GMAT Club Premium Membership - big benefits and savings

Magoosh GMAT Instructor
Joined: 28 Nov 2011
Posts: 301
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

12 May 2012, 15:47
2
Hi Metallicafan,

It seems as though you are making your own assumption when you defend (A). That for there to be more nitrogen in the atmosphere, there need only be more frozen nitrogen. If that were the case, then the answer could be (A).

Also, I think that when the argument says, "Since the proportion of any gas..." that is a premise upon which the conclusion (the distribution of methane, etc.) is based. When looking for an assumption, we want to find that gap between the premise and the conclusion.

Let me know if that makes sense
_________________

Christopher Lele
Magoosh Test Prep

Magoosh GMAT Instructor
Joined: 28 Nov 2011
Posts: 301
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 May 2012, 13:07
1
The conclusion states that, in decreasing abundance, the elements on Pluto are nitrogen, carbon monoxide, and methane. This conclusion assumes that there are no other elements that would disrupt this ranking. Namely, an element that would vaporize less readily than carbon monoxide or more readily than methane.

Hope that helps!
_________________

Christopher Lele
Magoosh Test Prep

Senior Manager
Status: You have to have the darkness for the dawn to come
Joined: 09 Nov 2012
Posts: 289
Daboo: Sonu
GMAT 1: 590 Q49 V20
GMAT 2: 730 Q50 V38
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

11 Nov 2016, 23:13
[quote="chunjuwu"]Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Plutoâ€™s atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.

The astronomersâ€™ argument relies on which one of the following assumptions?

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.

Let's break down into premises and conclusion

Premsie 1:Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto.
Premise 2:Such ices have a tendency to vaporize, producing an atmosphere.
Premise 3: The proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes.

Conclusion: astronomers have concluded that the components of Plutoâ€™s atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.
As per the conclusion N2> CO> CH4

Think for a moment how astronmers conclude "N2> CO> CH4" based on the above primises
Possible assumption: rate of evaporation of N2 is greater than CO and rate of evoparation of CO is greater than CH4.
In one premise it was wtitten any (hilighted in red).
on the basis of this
No gas comes in between N2 and CO and in between CO and CH4.

Let's POE

(A) IncorrectThere is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane. we cannot assume this because nothing related to this is indicated in the passage. So, A is Irrrevelant.

(B) IncorrectUntil space probes reach Pluto, direct analysis of the atmosphere is impossible. Out of scope. No way this helps us to achieve the conclusion

(C) CorrectThere is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. This mathches with our prethinking.
Don't forget to negate the correct option to checkoption's validity. If negated option invalidate the conclusion the that assumption is valid assumption.
Let's negate
There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. The negated version says there is some frozen substance in between then. Hence shatters our conclusion.

(D) IncorrectNitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet. Nothing such can be assumend.

(E) IncorrectA mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed. This option is of no help

Hence C
_________________

You have to have the darkness for the dawn to come.

Give Kudos if you like my post

Manager
Joined: 30 Sep 2015
Posts: 52
Location: United States (MD)
Concentration: Marketing, Entrepreneurship
GMAT 1: 620 Q49 V25
GMAT 2: 620 Q49 V27
WE: Marketing (Consumer Products)
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 Nov 2016, 10:40
Here is my analysis

Argument structure
Conc: Astronomers have concluded that the components of Pluto's atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.
Basis of concusion (P): Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes,
P1: Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto.
P2: Such ices have a tendency to vaporize, producing an atmosphere.

Pre-thinking
First thing to notice when you start reading the argument is that S analysis revealed the existence of 3 elements in Pluto (so you assume that could be more elements). But when you reach the conclusion, the author says that Astronomers have concluded that the components of Pluto's atmosphere are the same 3 elements (so no more element in Pluto's atmosphere). Now, the basis of the conclusion says that the abundance of each element in the atmosphere depends on how easily the frozen elements evaporate. Because the conclusion establishes an order of the abundance of each gas in Pluto's atmosphere, one can assume that there are only 3 element, that Nitrogen is the most abundant, and that CO is the least abundant.

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane. Incorrect
No clue about the abundance of frozen gases in Pluto's surface.

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible. OFS.

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. Correct!
Aligned with pre-thinking. If negated, the conclusion of scientists is shattered.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet. OFS
Too broad in scope.. we are talking about Pluto in the argument. We can not make that generalization.

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed. OFS
Too broad in scope.. we are talking about Pluto in the argument. Nothing is mention about Solar System
Manager
Joined: 10 Apr 2015
Posts: 180
GPA: 3.31
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

23 Mar 2017, 05:28
1
Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Plutoâ€™s atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.

The astronomers' argument relies on which one of the following assumptions?

(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.
This is part of conclusion which can be inferred, not an assumption to reach the conclusion.

(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.
Irrelevant.

(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.
The abundance sequence: N2 > CO > CH4
The vaporization seq : N2 > CO > CH4

There is no 'x' such that N2 > CO > x > CH4

If there is any 'x' which satisfies the above condition, then conclusion that N2 > CO > CH4 will be wrong.

So, author has assumed it.

Correct.

(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.

It is not only true about N2, but also for all of the gases.

(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.
Irrelevant.
_________________

In case you find my posts helpful, give me Kudos. Thank you.

Intern
Joined: 16 Jul 2018
Posts: 13
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 Oct 2018, 16:03
ywilfred wrote:
Here's a diagramming of the passage I did.

1) Spectroscopic analysis revealed existence of frozen nitrogen, methane and carbon monoxide on surface of pluto
2) Such ice have tendency to vaporize, producing an atmosphere
3) Proportion of gas in atmosphere depends directly on how readily corresponding ice vaporize
4)Astronomers concluded that components of Pluto's atmosphere are nitrogen, Carbon monixide and methane in decreasing abundance.

1, 2 and 3 are premises --> All facts
4 is a conclusion --> A claim (made by the astronomers)

In decreasing abundance means in Pluto's atmosphere, there is more nitrogen, than carbon monxide, and more carbon monxide than methane. It's talking about the gases that make up the atmosphere, and telling us which gas is higher in proportion.

Based on premise 3, if the conclusion is true, nitrogen vaporizes the fastest, followed by carbon monoxide, and methane.

Now we'll look at answer choice (C).

"There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. "

In order for the astronomer's claim that nitrogen is highest in proportion followed by carbon monoxide then methane, we need a statement that tells us that the proportion is indeed in this order.

(C) does that perfectly. It tells us there is no frozen substance (e.g. frozen oxygen) that vaporizes faster than methane but slower tan carbon monoxide
Intern
Joined: 16 Jul 2018
Posts: 13
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen  [#permalink]

### Show Tags

15 Oct 2018, 16:07
ywilfred wrote:
Here's a diagramming of the passage I did.

1) Spectroscopic analysis revealed existence of frozen nitrogen, methane and carbon monoxide on surface of pluto
2) Such ice have tendency to vaporize, producing an atmosphere
3) Proportion of gas in atmosphere depends directly on how readily corresponding ice vaporize
4)Astronomers concluded that components of Pluto's atmosphere are nitrogen, Carbon monixide and methane in decreasing abundance.

1, 2 and 3 are premises --> All facts
4 is a conclusion --> A claim (made by the astronomers)

In decreasing abundance means in Pluto's atmosphere, there is more nitrogen, than carbon monxide, and more carbon monxide than methane. It's talking about the gases that make up the atmosphere, and telling us which gas is higher in proportion.

Based on premise 3, if the conclusion is true, nitrogen vaporizes the fastest, followed by carbon monoxide, and methane.

Now we'll look at answer choice (C).

"There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. "

In order for the astronomer's claim that nitrogen is highest in proportion followed by carbon monoxide then methane, we need a statement that tells us that the proportion is indeed in this order.

(C) does that perfectly. It tells us there is no frozen substance (e.g. frozen oxygen) that vaporizes faster than methane but slower tan carbon monoxide

I agree completely with the way you analyze the structure of the argument. However, I disagree with the conclusion that C is the correct answer.

C is asserting something that is false according to the passage. From the given composition of the gases in the atmosphere, Nitrogen has to vaporize more readily than Carbon Monoxide. So the passage does assert that there is indeed a frozen substance that vaporizes more readily than Carbon Monoxide.

So my choice from what's given will be D but still, that too has problems of its own. If it is possible to have other sources for Nitrogen, then the vaporization phenomena no longer fully explain the composition of the atmosphere. However, since Nitrogen is the most abundant, the given ordering of the proportions will still hold.

Is my understanding correct? If so, is this a good question at all?
Re: Spectroscopic analysis has revealed the existence of frozen nitrogen   [#permalink] 15 Oct 2018, 16:07
Display posts from previous: Sort by