Last visit was: 22 Dec 2024, 13:58 It is currently 22 Dec 2024, 13:58
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

Close

GRE Prep 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
Your Progress

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

Practice
Pays

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC

Eight percent of the Earth's crust is aluminum, and there ar

SORT BY:
Date
Kudos
Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30472
Own Kudos [?]: 36818 [4]
Given Kudos: 26100
Send PM
Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   13 Jan 2020, 03:29
2
Expert Reply
2
Bookmarks
Question 1
00:00

Question Stats:

58% (02:00) correct 42% (02:12) wrong based on 85 sessions

Hide Show timer Statistics

Question 2
00:00

Question Stats:

73% (01:12) correct 27% (01:35) wrong based on 74 sessions

Hide Show timer Statistics

Question 3
00:00

Question Stats:

88% (00:59) correct 12% (01:10) wrong based on 67 sessions

Hide Show timer Statistics

Kudos for the right answer and explanation


Eight percent of the Earth's crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the rocks that contain them. The best aluminum ore. is bauxite, defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides. Bauxite is the richest of all those aluminous rocks that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum. Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum. Most of the many abundant nonbauxite aluminous minerals are silicates, and, like all silicate minerals, they are refractory, resistant to analysis, and extremely difficult to process. The aluminum silicates are therefore generally unsuitable alternatives to bauxite because considerably more energy is required to extract alumina from them.



17. The author implies that a mineral must either be or readily supply which of the following in order to be classified as an aluminum ore?

(A) An aggregate
(B) Bauxite
(C) Alumina
(D) Corundum
(E) An aluminum silicate


18. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:

(A) What percentage of the aluminum in the Earth's crust is in the form of bauxite?
(B) Are aluminum-bearing nonbauxite minerals plentiful?
(C) Do the aluminous minerals found iIi bauxite contain hydrated oxides?
(D) Are aluminous hydrated oxides found in rocks?
(E) Do large quantities of bauxite exist?


19. The author implies that corundum would be used to produce aluminum if

(A) corundum could be found that is not contaminated by silicates
(B) the production of alumina could be eliminated as an intermediate step in manufacturing aluminum
(C) many large deposits of very high-quality corundum were to be discovered
(D) new technologies were to make it possible to convert corundum to a silicate
(E) manufacturers were to realize that the world's supply of bauxite is not unlimited

ShowHide Answer Question #1
Official Answer
C
ShowHide Answer Question #2
Official Answer
A
ShowHide Answer Question #3
Official Answer
C
avatar
B
Ashgre
Retired Moderator
Joined: 18 Oct 2018
Posts: 148
Own Kudos [?]: 182 [2]
Given Kudos: 27
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 04:36
2
1. The author implies that a mineral must either be or readily supply which of the following in order to be classified as an aluminum ore?

The passage says that "and it yields alumina, the intermediate product required for the production of aluminum". Therefore C is the best option.

2. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:

Although it says "Bauxite is the richest of all those aluminous rocks that occur in large quantities", it does not specify a percentage, So option A is the answer.

3. The author implies that corundum would be used to produce aluminum if?

We can reference the answer from the sentence: Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits. Hence option C fits best.
avatar
BelalHossain
Manager
Manager
Joined: 23 Dec 2019
Posts: 50
Own Kudos [?]: 47 [4]
Given Kudos: 0
Concentration: Finance, Economics
GMAT 1: 690 Q47 V38
GRE 1: Q165 V155
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 22:32
4
Eight percent of the Earth's crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the rocks that contain them [Historical Facts]

The best aluminum ore. is bauxite [Main Idea], defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides.

Bauxite is the richest of all those aluminous rocks [Supporting Main Idea] that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum.

Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum [Supporting Main Idea].

Most of the many abundant nonbauxite aluminous minerals are silicates, and, like all silicate minerals, they are refractory, resistant to analysis, and extremely difficult to process. [Supporting next sentence]

The aluminum silicates are therefore generally unsuitable alternatives to bauxite [Supporting Main Idea] because considerably more energy is required to extract alumina from them.
avatar
BelalHossain
Manager
Manager
Joined: 23 Dec 2019
Posts: 50
Own Kudos [?]: 47 [2]
Given Kudos: 0
Concentration: Finance, Economics
GMAT 1: 690 Q47 V38
GRE 1: Q165 V155
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 22:46
2
Main idea:
The best aluminum ore. is bauxite [because it produces alumina]
Corundum [because corundum is not found in large deposits of high purity] and aluminum silicates [because they are extremely difficult to process] [b]are not suitable alternatives to bauxite. [/b]
avatar
BelalHossain
Manager
Manager
Joined: 23 Dec 2019
Posts: 50
Own Kudos [?]: 47 [0]
Given Kudos: 0
Concentration: Finance, Economics
GMAT 1: 690 Q47 V38
GRE 1: Q165 V155
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 22:51
BelalHossain wrote:
Main idea:
The best aluminum ore. is bauxite [because it produces alumina]
Corundum [because corundum is not found in large deposits of high purity] and aluminum silicates [because they are extremely difficult to process] [b]are not suitable alternatives to bauxite. [/b]


Q17:
WHY bauxite is The best aluminum ore?
because it produces alumina.
That means to be an aluminum ore, one has to produce/supply alumina.
avatar
BelalHossain
Manager
Manager
Joined: 23 Dec 2019
Posts: 50
Own Kudos [?]: 47 [0]
Given Kudos: 0
Concentration: Finance, Economics
GMAT 1: 690 Q47 V38
GRE 1: Q165 V155
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 22:54
BelalHossain wrote:
Main idea:
The best aluminum ore. is bauxite [because it produces alumina]
Corundum [because corundum is not found in large deposits of high purity] and aluminum silicates [because they are extremely difficult to process] [b]are not suitable alternatives to bauxite. [/b]


Ques 19: Why Corundum is not good alternative to bauxite? because corundum is not found in large deposits of high purity.
How Corundum can be a good alternative to bauxite>>>> if corundum is found in large deposits of high purity [Just crossing NOT from both side].
avatar
BelalHossain
Manager
Manager
Joined: 23 Dec 2019
Posts: 50
Own Kudos [?]: 47 [0]
Given Kudos: 0
Concentration: Finance, Economics
GMAT 1: 690 Q47 V38
GRE 1: Q165 V155
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   14 Jan 2020, 23:07
BelalHossain wrote:
Eight percent of the Earth's crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the rocks that contain them [Historical Facts]

The best aluminum ore. is bauxite [Main Idea], defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides.

Bauxite is the richest of all those aluminous rocks [Supporting Main Idea] that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum.

Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum [Supporting Main Idea].

Most of the many abundant nonbauxite aluminous minerals are silicates, and, like all silicate minerals, they are refractory, resistant to analysis, and extremely difficult to process. [Supporting next sentence]

The aluminum silicates are therefore generally unsuitable alternatives to bauxite [Supporting Main Idea] because considerably more energy is required to extract alumina from them.


18. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:

(A) What percentage of the aluminum in the Earth's crust is in the form of bauxite? First line does not give info about bauxite

(B) Are aluminum-bearing nonbauxite minerals plentiful?
Most of the many abundant nonbauxite aluminous minerals are silicates

(C) Do the aluminous minerals found iIi bauxite contain hydrated oxides?
The best aluminum ore. is bauxite [Main Idea], defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides.

(D) Are aluminous hydrated oxides found in rocks?
Bauxite which is present as hydrated oxides is the richest of all those aluminous rocks

(E) Do large quantities of bauxite exist?
Bauxite is the richest of all those aluminous rocks [Supporting Main Idea] that occur in large quantities
avatar
cnk1
Retired Moderator
Joined: 19 May 2020
Posts: 74
Own Kudos [?]: 192 [0]
Given Kudos: 0
GRE 1: Q160 V163
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   30 May 2020, 17:27
1
17. The author implies that a mineral must either be or readily supply which of the following in order to be classified as an aluminum ore?
(C) Alumina
correct: Bauxite………yields alumina, the intermediate product required for the production of aluminum.
The aluminum silicates……… more energy is required to extract alumina from them.

18. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:
(A) What percentage of the aluminum in the Earth's crust is in the form of bauxite?
Correct-

19. The author implies that corundum would be used to produce aluminum if
(C) many large deposits of very high-quality corundum were to be discovered
correct-
but corundum is not found in large deposits of high purity, and therefore it is
an impractical source for making aluminum
User avatar
S
Redfinger
Manager
Manager
Joined: 15 May 2021
Posts: 59
Own Kudos [?]: 35 [0]
Given Kudos: 92
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   06 Jun 2021, 01:24
17. The author implies that a mineral must either be or readily supply which of the following in order to be classified as an aluminum ore?

Bauxite is the richest of all those aluminous rocks that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum.

Answer: (C) Alumina

18. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:

(B)Most of the many abundant nonbauxite aluminous minerals are silicates

(C)The best aluminum ore. is bauxite, defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides

(D)(E)Bauxite is the richest of all those aluminous rocks that occur in large quantities

So, the correct answer choice is (A) What percentage of the aluminum in the Earth's crust is in the form of bauxite?

19. The author implies that corundum would be used to produce aluminum if

Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum

(C) many large deposits of very high-quality corundum were to be discovered
avatar
G
taskforce
Manager
Manager
Joined: 19 Feb 2021
Posts: 183
Own Kudos [?]: 179 [0]
Given Kudos: 425
GRE 1: Q170 V170
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   08 Jun 2021, 09:40
Q:The author implies that a mineral must either be or readily supply which of the following in order to be classified as an aluminum ore?
A:and it yields alumina, the intermediate product required for the production of aluminum.
SO AC C is correct.

Q:The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:
A: If we look at the first answer choice then we can see that there is no mention of the percentage of bauxite among aluminum ores SO it is the correct answer.

Q:The author implies that corundum would be used to produce aluminum if
A:Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum. So the conclusion is that if corundum is available in large deposits of high quality then it would be considered for aluminum mining.
User avatar
VerbalBot
SVP
SVP
Joined: 07 Jan 2021
Posts: 1732
Own Kudos [?]: 54 [0]
Given Kudos: 0
Send PM
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink] New post   04 Jul 2022, 12:11
Hello from the GRE Prep Club VerbalBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Prep Club for GRE Bot
gmatclubot
Re: Eight percent of the Earth's crust is aluminum, and there ar [#permalink]
04 Jul 2022, 12:11
Moderators:
bronaugust
GRE Forum Moderator
37 posts
VibhuAnurag
GRE Instructor
234 posts
HarishKumar
GRE Instructor
1066 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact