Questions tagged [materials]

Material is a general term for a chemical substance or a mixture of substances with certain, well defined physical properties.

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90
votes
8answers
50k views

Is toothpaste solid or liquid?

My teacher didn't answer this properly: Is toothpaste solid or liquid? You can't say toothpaste is a solid because solid material have a fixed shape but toothpaste doesn't. However, you can't say ...
39
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4answers
17k views

Why can a diamond be broken using a hammer if it's the hardest natural substance known?

I've heard that diamond is the hardest natural known material but, on Google search, I found that it can easily be broken by a hammer as it's not tough. So, what is difference between hardness ...
32
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3answers
4k views

Why isn't 'chemically-strengthened glass' made with potassium carbonate to begin with?

Instead of making potassium-strengthened glass by creating ordinary soda-lime glass first, then replacing the sodium atoms/ions with potassium by putting the glass in a bath/solution of potassium ...
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2answers
2k views

What makes Gorilla Glass more durable with each generation?

Gorilla Glass (GG) is one of the most recognizable brands of toughened glasses today, thanks to their marketing and widespread usage in various gadgets and automobile industry. According to Wikipedia,...
25
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3answers
13k views

Which is the densest gas known?

Which is the densest gas known to exist under normal "shirt sleeve" conditions: room temperature, one atmosphere, won't explode on contact with air, won't kill everyone in the building in trace ...
24
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1answer
21k views

Why does sunlight cause colors to fade?

If you leave something outside, its colors seem to inevitably fade or bleach due to exposure. Is this due to UV absorption? What sort of mechanism causes this - is it that man-made dyes deform on a ...
22
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2answers
35k views

Why does diamond conduct heat better than graphite?

Our teachers made us accept (without any explanation) that diamond conducts heat better than graphite. What is the reason behind this (alleged) fact?
21
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7answers
6k views

How to solidify sand

I'm doing a research project where we analyzing the structure of sand after a certain process. To get a better idea of the internal structure of the sand, we use different colors to visualize the ...
20
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3answers
3k views

Why is gold so popular in nanotechnology?

Gold is a very popular metal in nanotechnology. It is often used as a substrate in electronic applications, as a core of functionalized nanoparticles, and more. Why is gold so attractive? Why are ...
18
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2answers
3k views

If you put two blocks of an element together, why don't they bond?

Say you have two lumps or blocks of an element, like lithium for example, say in the form of two bars. Why, when you bring the two bars together so that they touch each other, do they not instantly ...
17
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2answers
246 views

Rock that transfers image

This is a question that has been bugging me for over 15 years! In high school while studying elements our teacher showed us a clear white rock or element. It was simply flat on both sides but when ...
17
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2answers
1k views

Safety in handling of concentrated ammonium fluoride

I recently saw a protocol for extracting organic materials that are bound in the silica matrix formed by diatoms. The extraction protocol used 10 molar ammonium fluoride ($\ce{NH4F}$). I briefly ...
16
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2answers
2k views

What does “René” mean in René alloys?

René alloys are nickel-based super alloys (René 41, René 88, René N5 etc. etc.). But how did it get the name René? Is it an acronym or contraction of other terms? It was created by Earl Ross and the ...
16
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1answer
3k views

What material are heat bags made of?

I just bought a heat bag from store and it has special property. It is made up of transparent plastic bag and transparent unknown liquid inside when sold. There is a tiny circular metal piece in ...
15
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3answers
7k views

Is there a point at which Ethanol (E10) fuel becomes harmful to gas tanks or engines if not used?

This is not the typical chemistry question on this website, but I think it's an important practical question. When I got a gas string trimmer, the woman who worked at the gardening shop told me that ...
15
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1answer
565 views

What chemical characteristics give types of steel their properties?

I am a mechanical engineer, and just like everyone else I had classes on the crystal structure of metals, phase diagrams, and the various heat treatments. However, even after diving back into that ...
14
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1answer
2k views

What happens if a polymer's length is equal to its persistence length?

So, I've been looking into polymer chemistry to model breaking polymers for a biological model, and I've been a bit stumped by the concept of persistence length. I know that if a polymer is ...
14
votes
1answer
4k views

How does epoxy stick to stuff?

According to Wikipedia what gives epoxy its holding power is apparently "ionic" interactions between the epoxy and the surface. But I thought that epoxy was overall neutral when cured. How can it ...
12
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1answer
478 views

Jahn-Teller Metal : The new state of matter

Recently it came in the news that scientists have discovered a new state of matter called Jahn-Teller metal. I tried reading up on it but couldn't understand it clearly. Please explain in simple ...
12
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0answers
188 views

Densest hydrogen storage medium [closed]

What compounds or nanostructures contain the most hydrogen atoms per unit of volume in realistic conditions (under 1 GPa). Particularly boron-free compounds because it's to be used in sci-fi nuclear ...
11
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3answers
4k views

Which materials/compounds expand in response to cold temperatures?

Which materials or compounds expand in response to cold temperatures? This material or compound should expand at a slow (but constant rate), from about 0–20 months when in the following temperature ...
11
votes
1answer
375 views

What do these mineral classification symbols mean?

For my birthday I got an awesome mineral specimen case, as pictured below. What piqued my interest was the notations in the lid where the minerals are described with 5 specifications: C (obviously for ...
10
votes
4answers
2k views

How does polydimethylsiloxane stick to glass?

Polydimethylsiloxane (PDMS) is the main ingredient in Rain-X, a treatment that adheres to windshields. How does PDMS adhere to class? It can't form covalent Si-O bonds with glass, according to one ...
10
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1answer
11k views

Structure of carbon fiber

What is the structure of carbon fiber? Wikipedia doesn't give much insight. The atomic structure of carbon fiber is similar to that of graphite, consisting of sheets of carbon atoms (graphene ...
10
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1answer
337 views

Why are isotopically pure diamonds 50% more thermally conductive than other diamonds?

A laboratory grown type-IIa diamond (no nitrogen defects) has a lambda of $\pu{1800-2200 W/mK}$, but an isotopically pure diamond of $\ce{^{12}C}$ can have up to $\pu{3320 W/mK}$. Why are $\ce{^{12}C}...
10
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2answers
750 views

Brass Instrument: Dezincification or just scrubbed off?

I do own a brass instrument (a trombone). The lacquer is damaged. I asked how to deal with it here. Now I learned that the brass contains zinc, and there is a corrosion process called "...
9
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2answers
2k views

Have we ever created artificial metals?

I really don't know anything about chemistry, but I was wondering about the following vague question: has any substance been created that does not contain any metallic elements, but is metallic? In ...
9
votes
2answers
205 views

Technical name for the holes (missing electrons) in a p-type semi-conductor?

When a pure silicon crystal (giant lattice) is doped with boron atoms one of the four covalent bonds made between one boron atom and four surrounding silicon atoms is missing an electron as boron has ...
9
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1answer
131 views

Materials used in metallic glass

I've been looking over the lists of materials used together to make metallic glass. Is it purely coincidental that if you round up/down any decimals from the atomic weight of elements used to ...
9
votes
1answer
3k views

What is the world's finest powder substance?

What is the world's finest powder substance that has the smallest granules but remains solid?
9
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0answers
445 views

How to predict the type of intrinsic defect? [closed]

Intrinsic defects occur when a pure material crystal shows either vacancy or interstitialcy. When an ionic compound has vacancy, the imbalance in charge has to be compensated with another defect. When ...
8
votes
1answer
5k views

What makes teflon such a strong material?

I don't know much about polymers but recently teflon made me get addicted to study their properties and nature. As far as I know, the teflon polymer contains fluorine which is one of the most ...
8
votes
2answers
514 views

Oxidation state of hydrogen in the LaNi5H intermetallic

This question is from an introductory chemistry course: What is the oxidation state of $\ce{H}$ in $\ce{NaH}$, $\ce{HCl}$, and $\ce{LaNi5H}$? I've looked in the textbook to no avail. Google ...
7
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2answers
1k views

Storing large quantities of KOH

I need to handle large quantities of $\ce{KOH}$; close to 1000 liters of 85 % conc $\ce{KOH}$ for about an hour. Any suggestions on how I go about doing it? Also the temperature during the process ...
7
votes
2answers
26k views

Why are so many ionic compounds brittle?

Even when ionic compounds are strong (e.g. rubies and sapphires), they are neither malleable nor ductile in the slightest, and if sufficient stress is put on them, they will shatter, not bend. Why is ...
7
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4answers
1k views

Can flexible plastics have reflective coating (vacuum metalized)?

Is it possible to achieve an optical mirror coating to a flexible plastic part? If vacuum metalization is possible, would the reflective coating layer be durable enough to withstand the bending of a ...
7
votes
2answers
22k views

Which kind of plastic material would be suitable for a clutch cover on a motorcycle transition?

I'm going to have an online machine shop build a part for me using a CAD drawing that I specify. Typically, these parts are made of aluminium, but this manufacturer also mills parts out of these ...
7
votes
1answer
5k views

change in state (sublimation and deposition)

I am slightly confused as to how I should think of changes in state (especially sublimation and deposition). Should I think of sublimation and deposition as skipping the liquid phase (fig 1) or should ...
7
votes
1answer
13k views

What type of organic compounds are used in OLED technology?

I know that there are organic compounds that exhibit electroluminescence, and are those types of materials difficult to synthesize?
7
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2answers
10k views

Easily removable material that sticks to skin

I am looking for some kind of material that can be used to easily latch something to someone's finger. This is for a first year engineering project. The idea is to use this material to latch small ...
7
votes
2answers
1k views

Why do shape and size have the greatest effect on the optical properties of nanoparticles?

The LSPR properties of nanoparticles depend on a number of factors, including shape, size, material, crystal structure, dielectric environment, etc. However, it has been consistently shown that shape ...
7
votes
1answer
921 views

What gas has the highest refractive index? [closed]

Coming from this answer on the Worldbuilding stack, I'm trying to find a gas with a high refractive index in the visible light wavelengths. The highest index on this site, is chlorine at 1.000773. Is ...
7
votes
1answer
147 views

What structural property creates stickiness?

Recently, me and my mom parked her car in a spot reserved for customers of a super expensive shoe store while going to get some also fairly expensive drinks at Starbucks. When we came back, an ...
7
votes
2answers
333 views

What is Nano Zinc Oxide?

First of all, I have zero chemical background, but I seek for an easy explanation about Nano Zinc Oxide. I was told that the name of "Nano Zinc Oxide" couldn't possibly exist. Instead, it should be ...
7
votes
0answers
576 views

What is the fabric in heating mantles made of?

An ordinary lab heating mantle often has a white fabric coating for the flask compartment, which looks like an inorganic fiber: Image source I'm pretty sure that for some time in the past ...
6
votes
2answers
5k views

Are there two compound resins that tolerate over 1000°C for glass/carbon fiber?

I'm a hobby enthusiast that loves to play with electronics so my major is not in chemistry, there for I'm hoping that this forum is the right place to find aid in this question. I've searched day in ...
6
votes
1answer
3k views

How can one test if a ruby is real?

My friend recently bought a ruby gem from a store and asked me how to test whether its an original one or a duplicate. Are there any ways to test it using only domestic materials?
6
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4answers
10k views

Will fire corrode stainless steel?

I am considering building a stove out of stainless steel. I want to us stainless steel because the stove will have a double outer jacket to pass water through and heat it. Will a wood fire sitting ...
6
votes
3answers
5k views

What new material is D3O?

I am a PhD student in materials engineering. What is D3O? It is not a chemical, but rather a "polyurethane energy-absorbing material" (from Wikipedia). I would wish to know and study the chemical ...
6
votes
1answer
3k views

What is the difference between an amorphous solid and glass?

They are both formed when a liquid is supercooled rapidly, no free energy, and they both have irregular structures. What defines a glass other than how it is amorphous, transparent, and has a glass ...

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