[ben1793]

Thanks for the hlpful information.

What is confusing me is that in the past I was told that every material has atoms that consist of a newcleus(protons/neutrons) and electrons orbiting it like this example for the tugsten http://www.chemicale.../bohr/b0074.gif (sorry dont know how I changed the colour of the text, cant change back ) so if this is true there should be images of atoms for the other materials, are you saying there is no images of the atoms for the other materials or do you mean there are many different types of atoms for each material?

All I need is the picture of the atoms, not the strctures yet, just to confirm, you are saying that each material consists of many atoms and just one image of the atom is not possible to obtain?

This post has been edited by ben1793: 8 February 2012 - 04:17 PM

[hypervalent_iodine]

That is what I am saying, yes. H₂O for instance contains 3 atoms; 2 hydrogen atoms and 1 oxygen atoms. The polymeric materials you've listed can contain many hundreds or even thousands of atoms.

[ben1793]

hypervalent_iodine, on 8 February 2012 - 04:43 PM, said:

That is what I am saying, yes. H₂O for instance contains 3 atoms; 2 hydrogen atoms and 1 oxygen atoms. The polymeric materials you've listed can contain many hundreds or even thousands of atoms.

Thank you,I think I am starting to understand now!
Sorry I am very bad at chemistry but it is part of the course, so something like polyethelene or silicon carbide cant be shown as one atom in a image for example cant be something like example silicon carbide - xxneutrons xx protons xx electrons, there are many different atoms so it is not possible to show it as one atom?

The tugsten, is that only one atom? because that atomic structure is shown (http://www.chemicale.../bohr/b0074.gif) meaning there is only one type of atom used in it?

Also if all that is correct, how many atoms do you think there would be in the materials I liseted, like silicon carbide?

Thank you and again, I am sorry I am so bad at chemistry.

This post has been edited by ben1793: 8 February 2012 - 05:10 PM

[hypervalent_iodine]

The molecular formula of tungsten is simply W, so one molecule of tungsten is only one atom. The image you have is a crystal structure and it represents what many molecules look like when they stack together. All of the rest of your materials contain more than one atom within its molecular structure. The empirical formula of silicon carbide contains two atoms, SiC, and these are bound to other molecules of SiC in the crystal structure of the bulk material. It is a similar story with the rest of them.

I couldn't tell you how many atoms are in the polymeric materials. You'll notice the image I included in post 7 contains two CH₂ groups within brackets with a subscript 'n'. That n represents some integer value and tells you how many repeating units of CH₂CH₂ there are. The value of that number is not predefined and is not even consistent within a single sample of a material, so telling you how many atoms there are in those compounds is impossible to do.

Also, as an aside. From our discussion here, it seems to me that it would be very much worth your while to take a general chemistry course. I'm not meaning to be insulting, I just think that having an idea of the fundamental concepts of chemistry would be valuable to you in your degree, which I think this assignment of yours has shown.

[ben1793]

hypervalent_iodine, on 8 February 2012 - 10:38 PM, said:

The molecular formula of tungsten is simply W, so one molecule of tungsten is only one atom. The image you have is a crystal structure and it represents what many molecules look like when they stack together. All of the rest of your materials contain more than one atom within its molecular structure. The empirical formula of silicon carbide contains two atoms, SiC, and these are bound to other molecules of SiC in the crystal structure of the bulk material. It is a similar story with the rest of them.

I couldn't tell you how many atoms are in the polymeric materials. You'll notice the image I included in post 7 contains two CH₂ groups within brackets with a subscript 'n'. That n represents some integer value and tells you how many repeating units of CH₂CH₂ there are. The value of that number is not predefined and is not even consistent within a single sample of a material, so telling you how many atoms there are in those compounds is impossible to do.

Also, as an aside. From our discussion here, it seems to me that it would be very much worth your while to take a general chemistry course. I'm not meaning to be insulting, I just think that having an idea of the fundamental concepts of chemistry would be valuable to you in your degree, which I think this assignment of yours has shown.

thank you! I unerstand it now, you are also right about the fundimental chemistry course, I will look one up because I really need to get better at chemistry, until I get into a course I will probably do my research on the internet, I have 1 weeks holiday next week and I will be on the internet researching about chemistry. I am at college today and will ask my teacher about the atoms and see what he exactly wants, again thank you for your help would have never learnt anything without you

[hypervalent_iodine]

Well, I appreciate the ego boost, but I'm sure you would have managed to learn at least something without me. If you have any more questions following discussion with your professor and/or during your break, feel free to come back and ask them.

[ben1793]

I have done some more research and also talked to my lecturer before the holidays and found that like you said in the past, some of the materials I have listed are without shape (no crystal structure), did some research and found these were called amorphous, he said from the top of his head he could tell me that polyethelene has no shape, I asked him about the others and he said if he remembers right tungsten does (which was BCC) and quartz crystal does, that is all he knew off the top of his head but he said all he wants is the structure like tungsten which was BCC, he says just show the type of structure for example (BCC, FCC, close packed hexagonal, http://www.askiitian...al%20system.JPG), I am a bit confused now, I know tungsten and quartz crystal definatly have crystal structure but I cant find any for either quartz crystal or the others (GFRP, silicon carbide, shape memory polymer) are some of these also without shape(amorphous)? Also the tungsten, I did some research and found different forms of the crystal, I think the BCC which I found is alpha but there are also two others beta and delta I think, I found that these are different structures because of the tempreture effecting the structure, what would the crystals look like for beta and delta?(this is just extra knowledge for me )

Now from what you said tungsten is made from the same atom not a combination of many so it is a element, the other materials are made from a combination of different atoms so this means they are compounds? how would I draw the atoms for the compounds, for example for silicon carbie(SiC) would I get a silicon atom and carbon atom and draw them with a covelant bond? would the bonds for the materials be different because I did some research and found that there are different bonds, covalent, ionic and metalic bonds from what I read the covalant is where the outer shell electrons are shared, the ionic is when one atom gives another its electron making one positivly charged and one negatively and they attratact and the metalic is where the electrons are free and the posotivly charged atoms all atract to the pool of electrons, is this correct or have I been reading wrong?

sorry for asking so many questions, hope it does not bother you, thank you for your help

This post has been edited by ben1793: 13 February 2012 - 05:01 PM

[hypervalent_iodine]

ben1793, on 13 February 2012 - 04:54 PM, said:

I have done some more research and also talked to my lecturer before the holidays and found that like you said in the past, some of the materials I have listed are without shape (no crystal structure), did some research and found these were called amorphous, he said from the top of his head he could tell me that polyethelene has no shape, I asked him about the others and he said if he remembers right tungsten does (which was BCC) and quartz crystal does, that is all he knew off the top of his head but he said all he wants is the structure like tungsten which was BCC, he says just show the type of structure for example (BCC, FCC, close packed hexagonal, http://www.askiitian...al%20system.JPG), I am a bit confused now, I know tungsten and quartz crystal definatly have crystal structure but I cant find any for either quartz crystal or the others (GFRP, silicon carbide, shape memory polymer) are some of these also without shape(amorphous)? Also the tungsten, I did some research and found different forms of the crystal, I think the BCC which I found is alpha but there are also two others beta and delta I think, I found that these are different structures because of the tempreture effecting the structure, what would the crystals look like for beta and delta?(this is just extra knowledge for me )

I think most of this was already mentioned/answered in this thread if you look through it. Did you find out which polymer he wanted for the memory shape and fibre glass? Chances are they are amorphous as well. Whether or not polyethylene is amorpous depends on what type it is, as I said already. LDPE is amorphous, HDPE is not.

Yes, there are different forms of tungsten, but I am not too familiar with the crystal structure. You should be able to look it up by searching beta crystal structure of tungsten, etc.. In any case, I went over all that on a previous post.

The quartz crystal structure you already had. Form memory, the image you had linked was the alpha form.

Quote

Now from what you said tungsten is made from the same atom not a combination of many so it is a element, the other materials are made from a combination of different atoms so this means they are compounds?

Yes.

Quote

how would I draw the atoms for the compounds, for example for silicon carbie(SiC) would I get a silicon atom and carbon atom and draw them with a covelant bond?

Have a look how it is drawn on wikipedia or have a look at how I drew the polyethylene a few posts back. If you were to draw it, you would simply draw a line between the Si and the C. Bear in mind that you can't isolate a single SiC molecule. The crystal structure is a continuous network of SiC units, all bound to one another.

Quote

would the bonds for the materials be different because I did some research and found that there are different bonds, covalent, ionic and metalic bonds from what I read the covalant is where the outer shell electrons are shared, the ionic is when one atom gives another its electron making one positivly charged and one negatively and they attratact and the metalic is where the electrons are free and the posotivly charged atoms all atract to the pool of electrons, is this correct or have I been reading wrong?

sorry for asking so many questions, hope it does not bother you, thank you for your help

Yeah, that's the crux of it. Ionic bonds occur between a metal and a non-metal. Si and C are both non-metals, so do not form ionic bonds but rather covalent bonds.

[ben1793]

Thank you for the help

The quartz crystals:
Alpha: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png
Is the alpha a Face Centered Cubic structure? EDIT: Done some more research, is this a Dimond Cubic Structure?
or a trigonal crystal?
Beta: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2b.png
Is this the correct structure for Beta-Quartz? Also, what type of structure is this (FCC,BCC,SC)? I have been trying to compare with the chart I have but I cant find a resembalance. EDIT: DID SOME MORE SESEARCH AND FOUND THE BETA I HAVE SHOWN IS INCORECT, IT IS SUPPOSED TO BE HEXAGONAL, IS THIS CORRECT?

What I read was that alpha beta and delta are crystal structures at different tempratures, will the tempreure range be the same for all the materials or for something like tungsten would the tempreture be different compared to beta-quartz?



For the Silicon Carbide is it possible to create a covalant bond with the atoms conected as images rather than text? I mean the images I had seen had two atoms conected by there electrons in the outer shell, would this be possible to do rather that the polyethelene example you had give because I need to draw them with the atoms and nucleus, I will give an example of the method you explained also but I am not sure if it is possible or not to do it directly with the atom diagram.

Also, like you said the silicon carbide crystal structure has about 250 different crystal structures, I did some research and found the 2 most common ones, the alpha and the beta structures.
alpha: Hexagonal
Beta: Cubic
Alpha is formed at temperatures above 1700 C and the beta is under 1700 C

Is this correct?

Thank you so much for your help.

This post has been edited by ben1793: 14 February 2012 - 10:58 PM

[ben1793]

This is an example of what I meant about drawing the covalent bonds:

[hypervalent_iodine]

ben1793, on 14 February 2012 - 01:06 PM, said:

Thank you for the help

The quartz crystals:
Alpha: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png
Is the alpha a Face Centered Cubic structure? EDIT: Done some more research, is this a Dimond Cubic Structure?
or a trigonal crystal?
Beta: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2b.png
Is this the correct structure for Beta-Quartz? Also, what type of structure is this (FCC,BCC,SC)? I have been trying to compare with the chart I have but I cant find a resembalance. EDIT: DID SOME MORE SESEARCH AND FOUND THE BETA I HAVE SHOWN IS INCORECT, IT IS SUPPOSED TO BE HEXAGONAL, IS THIS CORRECT?

Alpha is trigonal, beta is hexagonal.

Quote

What I read was that alpha beta and delta are crystal structures at different tempratures, will the tempreure range be the same for all the materials or for something like tungsten would the tempreture be different compared to beta-quartz?

I don't really know, sorry. In truth, I'm an organic chemist, so this is a little out of my depth.

Quote

For the Silicon Carbide is it possible to create a covalant bond with the atoms conected as images rather than text? I mean the images I had seen had two atoms conected by there electrons in the outer shell, would this be possible to do rather that the polyethelene example you had give because I need to draw them with the atoms and nucleus, I will give an example of the method you explained also but I am not sure if it is possible or not to do it directly with the atom diagram.

If you want them the same as in your last post, then yes, but it would be difficult and convoluted.

Quote

Also, like you said the silicon carbide crystal structure has about 250 different crystal structures, I did some research and found the 2 most common ones, the alpha and the beta structures.
alpha: Hexagonal
Beta: Cubic
Alpha is formed at temperatures above 1700 C and the beta is under 1700 C

Is this correct?

Thank you so much for your help.

Alpha is correct. The beta one is cubic; more specifically, it has a crystal crystal structure similar to diamond, called zincblende.

ben1793, on 16 February 2012 - 12:25 PM, said:

This is an example of what I meant about drawing the covalent bonds:

You could draw them like that, but I would only do it if you absolutely had to.

[ben1793]

THANK YOU THANK YOU THANK YOU, YOU ARE A GENIUS!

I was wondering about the covalent bonds, from looking at what you said and doing some more research I found that all atoms want to become NOBEL so does this mean when I am doing silicon carbide I will have to add more than one carbon atom to the silicon to make 8 electrons on the outer shell of the silicon atom or do I only have to add one atom to the silicon for the example?

Also the quartz crystal, I tried the link you gave me to find the atomic structure image (the one with the nucleus and electrons) but I could not find any, do you know any websites I could try or do you know anywhere where I could find one, I think the dificulty may be because it is a compound (I think) and that means I will be needing to do the same thing I am doing with silicon (find all the atoms and create a covalent bond).

Also, fibre glass, I have come to a conclusion after doing a great deal of research that this is also amorphous (without shape) so I will not find any crystal structure for this, is this correct? I have also realised that this is a compound and in your last post you said this consists of many materials, is there a way I could draw just fibre glass in a atomic structure with a combination of atoms combined with covalent bonding?

AGAIN...just want to say thank you, I have a week off and can not contact my teachers for help, you have been so much help

This post has been edited by ben1793: 17 February 2012 - 04:02 PM

[hypervalent_iodine]

ben1793, on 17 February 2012 - 01:52 PM, said:

I was wondering about the covalent bonds, from looking at what you said and doing some more research I found that all atoms want to become NOBEL so does this mean when I am doing silicon carbide I will have to add more than one carbon atom to the silicon to make 8 electrons on the outer shell of the silicon atom or do I only have to add one atom to the silicon for the example?

What you are referring to is called the octet rule. And yes, that is exactly what it means. If you look at the crystal structure you had of it, you'll see all of the SiC molecules are all joined together; each C is bound to 4 Si atoms and each Si atom is bound to 4 C atoms.

Quote

Also the quartz crystal, I tried the link you gave me to find the atomic structure image (the one with the nucleus and electrons) but I could not find any, do you know any websites I could try or do you know anywhere where I could find one, I think the dificulty may be because it is a compound (I think) and that means I will be needing to do the same thing I am doing with silicon (find all the atoms and create a covalent bond).

Wikipedia has some good images. I think I linked it a few posts back, but if not, you can find them here.

Quote

Also, fibre glass, I have come to a conclusion after doing a great deal of research that this is also amorphous (without shape) so I will not find any crystal structure for this, is this correct? I have also realised that this is a compound and in your last post you said this consists of many materials, is there a way I could draw just fibre glass in a atomic structure with a combination of atoms combined with covalent bonding?

Yeah, most likely. As I said on the last page somewhere, you can make fibreglass from a number of different polymers - either a thermoplastic or a thermosetting plastic (eg. epoxys, polyesters or polyvinyl esters). It is usually a combination of a couple of different polymers, so my recommendation would be to find an example of just one polymer and draw that.

Quote

AGAIN...just want to say thank you, I have a week off and can not contact my teachers for help, you have been so much help

That's alright, I enjoy helping where I can. I'm sorry I haven't been more attentive, I've been quite sick the past four or so days and haven't been very active.

This post has been edited by hypervalent_iodine: 18 February 2012 - 02:33 PM

[ben1793]

Quote

That's alright, I enjoy helping where I can. I'm sorry I haven't been more attentive, I've been quite sick the past four or so days and haven't been very active.

Thank you for your help, dont worry about it your health is much more important than my questions
Hope you get better soon

This post has been edited by ben1793: 18 February 2012 - 03:52 PM

[hypervalent_iodine]

Oh, feel free to keep asking more. I'm bored as anything stuck here in bed.

[mississippichem]

hypervalent_iodine, on 18 February 2012 - 04:35 PM, said:

Oh, feel free to keep asking more. I'm bored as anything stuck here in bed.

What is the square root of 17? Preferably to at least 26 decimal places.

[hypervalent_iodine]

Geez, off-topic much?

Wolfram to the rescue! The square root of 17 to 26 decimal places: 4.12310562561766054982140986

[ben1793]

haha, never knew about wolfram till you told me, its AMAZING.

So you said for quartz crystal the atomic structure is SiO₄ in an earlier post, so does this mean 1 silicon atom and 4 oxygens? So I am able to draw this just like I did for SiC by doing 1 silicon atom combined with 4 oxygens?

[hypervalent_iodine]

Have a look at the crystal structure. It just occurred to me that you might not have realised this, but the crystal structures show ball-and-stick models of your compound. Each ball represents an atom and each stick is a bond. They are usually colour coded; carbon is usually grey, oxygen is red, nitrogen blue, etc. In the quartz crystal structures shown on the wiki page, the Si atoms are represented in grey and the oxygen in red.

[ben1793]

hypervalent_iodine, on 18 February 2012 - 06:08 PM, said:

Have a look at the crystal structure. It just occurred to me that you might not have realised this, but the crystal structures show ball-and-stick models of your compound. Each ball represents an atom and each stick is a bond. They are usually colour coded; carbon is usually grey, oxygen is red, nitrogen blue, etc. In the quartz crystal structures shown on the wiki page, the Si atoms are represented in grey and the oxygen in red.

Ahhh, thank you, never realised that
I will use the link you sent me for the images of the alpha, beta crystal stuctures.
After looking at what you said about the crystal structure being related to atomic structure, would this mean just like crystal structures change at different tempratures the atomic structure would also change?
I am also wondering, how would the sturcture effect the strength of the material for example I mean like the alpha and beta crystal structures for quartz, how would the different structures effect the strength and other properties of the material?