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# Molten metal vs nonmetal

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Molten metal vs nonmetal [#permalink]  11 Apr 2017, 21:27
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When a molten metal or metallic alloy is cooled to a solid, a crystalline structure is formed that depends on the particular alloy composition. In contrast, molten nonmetallic glass-forming materials, when cooled, do not assume a crystalline structure, but instead retain a structure somewhat like that of the liquid--an amorphous structure. At room temperature, the natural long-term tendency for both types of materials is to assume the crystalline structure. The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other. Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.

It can be inferred from the passage that, theoretically, molten nonmetallic glasses assume a crystalline structure rather than an amorphous structure only if they are cooled
A very evenly, regardless of the rate
B rapidly, followed by gentle heating
C extremely slowly
D to room temperature
E to extremely low temperatures

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Re: Molten metal vs nonmetal [#permalink]  13 Apr 2017, 01:29
Expert's post
sdhar wrote:
When a molten metal or metallic alloy is cooled to a solid, a crystalline structure is formed that depends on the particular alloy composition. In contrast, molten nonmetallic glass-forming materials, when cooled, do not assume a crystalline structure, but instead retain a structure somewhat like that of the liquid--an amorphous structure. At room temperature, the natural long-term tendency for both types of materials is to assume the crystalline structure. The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other. Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.

It can be inferred from the passage that, theoretically, molten nonmetallic glasses assume a crystalline structure rather than an amorphous structure only if they are cooled
A very evenly, regardless of the rate
B rapidly, followed by gentle heating
C extremely slowly
D to room temperature
E to extremely low temperatures

The red parts suggest you that the faster the substance is cooled, the more the structure is influenced.

regards
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Re: Molten metal vs nonmetal [#permalink]  14 Apr 2017, 08:21
Carcass wrote:
sdhar wrote:
When a molten metal or metallic alloy is cooled to a solid, a crystalline structure is formed that depends on the particular alloy composition. In contrast, molten nonmetallic glass-forming materials, when cooled, do not assume a crystalline structure, but instead retain a structure somewhat like that of the liquid--an amorphous structure. At room temperature, the natural long-term tendency for both types of materials is to assume the crystalline structure. The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other. Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.

It can be inferred from the passage that, theoretically, molten nonmetallic glasses assume a crystalline structure rather than an amorphous structure only if they are cooled
A very evenly, regardless of the rate
B rapidly, followed by gentle heating
C extremely slowly
D to room temperature
E to extremely low temperatures

The red parts suggest you that the faster the substance is cooled, the more the structure is influenced.

regards

Y not D option?

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Re: Molten metal vs nonmetal [#permalink]  14 Apr 2017, 11:00
Expert's post
At room temperature is only a factual information AKA the context in which the process unfolds. It is not the answer.

Why there is difference in the atomic structure ?? because the way is more or less fast.
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Re: Molten metal vs nonmetal [#permalink]  15 Apr 2017, 05:01
Okay now I understood the point.thats why said It is mentioned in passage tht in nonmetallic glasses kinetic favours slow formation at any rate, right?

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Re: Molten metal vs nonmetal [#permalink]  15 Apr 2017, 06:41
Expert's post
Vrushali wrote:
Okay now I understood the point.thats why said It is mentioned in passage tht in nonmetallic glasses kinetic favours slow formation at any rate, right?

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yes.Exactly

The strategy is to read super very carefully the statement and then eliminate choice by choice until the right one comes up.

The tip is that in inference questions NEVER if an answer choice repeats the same words in some part of the stimulus is the right one. Simply because otherwise will not be an inference question.

Hope this helps
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Re: Molten metal vs nonmetal [#permalink]  15 Apr 2017, 11:45
Okay got that.
Thank you so much!

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Re: Molten metal vs nonmetal [#permalink]  15 Apr 2017, 21:52
I am still not able to understand how C is the answer. The last sentence - Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.

From this, we know that slow rate favors amorphous structure in nonmetal but which is the clue to infer that slow rate also favors crystalline in the nonmetal
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Re: Molten metal vs nonmetal [#permalink]  17 Apr 2017, 07:13
Expert's post
Because is the process is slow + kinetic and other factors you have X.

If the process is SO slow + kinetic and other factors you have Y.

The common denominator is at a room temperature.
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Re: Molten metal vs nonmetal   [#permalink] 17 Apr 2017, 07:13
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