How to know the shape of the molecule ?
965017
You need to know the number of valence electrons.  Carbon, for example, would want to pair with 4 other atoms.  If there were fewer atoms attached as in CH2O (only 3 attached to the carbon) then one of the atoms must be double bonded.  In this case it is the oxygen that would have the double bond.  You could deduce the approximate shape from the number of bonds.  It would be slightly distorted by the slight negative polarity of the oxygen atom.  Shape of a molecule is a complicated issue that I glossed over.
608500
Group of atoms form a molecule.\n\nA molecule can be made of two or more atoms. This atoms can be of the same type:\n\nCl2, H2, O2...\nO2= an oxygen molecule. It is made of two equal oxygen atoms\n\nOr of different types:\n\nCH4, HCl, NH3...\nCH4 = a methane molecule. It is made of 1 atom of Carbon and 4 equal atoms of hydrogen
541134
Your best bet is to go to your university library and look it up in the math and computer science section. There are books on this and if your library doesn't have them you can do an interlibrary loan to get them. To look extra smart, find an example in the literature and reference their work. Look up Peter Jurs' papers from Penn State University. They use genetic algorithms and neural networks to predict physical properties of molecules
1107805
study on intermolecular particals and there behavior
498491
This is an subject area where vocabulary is vital for clear understanding, to a degree I am not capable of, however the stuff that you ask about are so small that the only way to attempt to prove their existence is through mathematical formulae based on what we suspect to be true. Our lack of understanding on this subject, which is still very voung, means the answers available are sketchy at best compared to our understanding of molecular structure or atomic structure.\nWhat is known so far can be found in places like the noetic sciences knowledge centre, or wikipedia.
452453
No, we don't use the electronegativity chart; instead we draw the full structure of the molecule and then see which 'pulling of bonds' cancel each other. \nIn the molecule AsF3, since As has 5 outer most electrons(in group 5), each F is bonded to As with a single covalent bond. Hence, the shape of the molecule becomes trigonal pyramidal, with 3 bond pairs (with 3 F atoms) and 1 lone pair. The 3 bond pairs pull the electrons towards themselves in the lower plane, while the 1 lone pair pulls at the top. The pulling effect of the 2 F atoms at the 2 sides cancel out  because the pulling effect is the same for both F atoms; however, the pulling effect of the lone pair at the top and the 1 F bond pair at the bottom will not cancel, because it is not from the same atom/species. Hence the overall dipole moment( dipole moment = charge x distance) does not cancel out, so the molecule is polar, with some charge distribution remaining due to the unequal pulling effect.\n\nIn CF3Cl, the shape is tetrahedral, with the 3 Cl atoms and 1 F atom bonded by single covalent bonds to the central C atom. The bond pairs spread out with the 3 Cl atoms pulling at the bottom and the 1 F atom pulling at the top. The pulling effect of the 2 Cl atoms at the sides cancels out, but that of the F atom at the top and the Cl atom at the bottom does not, as the pullin effect of 2 different atoms is different. Hence, as before, overall dipole does not cancel and the molecule is hence polar.
84780
!!!!!!!!!!!!!!!! \nI think rather u wanted to ask how can u predict the formula of a chemical reaction!!\nFirstly, we have to determine the moles of reactant taking part.(It can be done easily, think A reacts with B, just mix 1 mole of A with the same amount of B.)\nThen determine what are the different products and their amounts.\nAll u have to do is some calculations..................\nRemember its not as easy as it sounds.
666235
The theory of valency which we have been developing is known as valence bond theory. One further feature of this theory is that it may be used to predict (or in some cases, rationalize) the observed geometries of molecules By the geometry of a molecule we mean the relative arrangement of the nuclei in three-dimensional space. For example, assuming the two O—H bonds in the water molecule to be similar and hence of the same length, the angle formed by the two O—H bonds (the HOH angle could conceivably posess any angle from 180° to some relatively small value. All we demand of our simple theory is that it correctly predict whether the water molecule is linear (bond angle = 180°) or bent (bond angle less than 180°)  Or as another example, it should predict whether the ammonia molecule is planar   or pyramidal \n \nhttp://www.chemistry.mcmaster.ca/esam/Chapter_6/section_4.html.
908225
Go to this site and it will show you structures of a whole bunch of molecules with Carbon and without, by formula and by name, kind of mess around with it for a while. http://www.chem.purdue.edu/gchelp/molecules/index.html
260431
R-O-CH3 \n\n R is any carbon based group. I wish I had chem draw on this computer, but the structure is actually bent due to the symmetry (this involves group theory - a linear algebra based idea in quantum mechanics) of the orbitals involved in bonding. Its bent for the same reasons that water is bent, now your teachers may say that water is bent due to electronic repulsions but if thats true how come they draw the lone pairs so close to eachother??? Its because its not true, and its part of VSEPR theory which is just a practicle method of teaching structure to people who dont know too much physics, math, and chemistry.
880416
TCATTG\n\nT molecules connect with A molecules\nC molecules connect with G molecules
963196
Many molecules have a lot more than two. You just have to keep counting. Don't forget the green ones.
87059
You should consult a chemistry textbook, if possible, or if not, look online for an answer; I'm sure there is information or a guide describing how to do it better than I can in a few short sentences. That said, the basic way to draw a molecule (often abbreviated mlcl) is to use each element's symbol(ie sodium=Na, carbon=C, etc) to denote an atom, and to draw a single, solid line for each bond between elements. This line/bond represents 2 electrons, aka one orbital. Most elements like to have 8 electrons in their valence (outermost) shells in order to be stable, but this doesn't always happen; there are many exceptions, hence my suggestion to look at a textbook or online text/guide.\n\nIt gets more complicated when you're dealing with things like organic chemistry or complexes or chelating agents where sharing of bonds/electrons is pretty common and there are more types of bonds. For a simple example, if you had a 6-carbon atom ring, each carbon has 6 electrons in its valence; it wants 8, so what happens, does it get frustrated with its misfortune and self destruct, destroy our little universe? Of course not... there are a total of (6)(6)=36 electrons, and we need (6)(8)=48. How is this possible? Clearly, 36 is not equal to 48. We can't create more. So what happens? As it turns out, carbon, along with most other elements, passed kindergarten with flying colors- they SHARE them, and since it's a symmetrical hexagon shape of identical atoms, they are shared equally. There are all kinds of crazy combos in which the electrons are shared unequally between atoms because of something called electronegativity, but our rules for drawing those lopsided things aren't very different. However, that's for another 'lesson;' don't worry about it for now.\n\nSo, in order to make the carbon happy, we have to share 12, or 6 pairs, of electrons. ([48 needed]-[36 that we have] = 12) \nSince this carbon ring has multiple resonance structures (atom config the same but electron pairs on different atoms), we draw six carbons in a hexagon, with one solid line bond between each, and a dotted circle in the middle- this accounts for all of its resonance structures and provides us with more info, in addition to only needing one drawing to display that info, than using single bond lines only.\n\nSo in conclusion, I've said way more than I really had to... from the level of generality of your question I assume that you don't know too much about chemistry; if you are confused with what I said, then do as I said- look up the info online or get a book. It's not too easy to understand right away but with some patience you should be able to figure it out just fine; good luck.
765234
1. To find the mass, first you need to find the atomic mass of each atom in the molecule. So:\nFe = 55.84 * 2 = 111.68\nS = 32.07\nO = 16 * 4 = 64\nand the (SO4) unit has 32.07 + 64 = 96.07\nSince there are three SO4 units in the molecule, thats 96.07 * 3 = 288.21 ; and adding the Fe, that's a total of 399.89 atomic mass units in the whole molecule.\n\nThat means that one mole of this molecule weighs 399.89 grams.\n\n2. Similar procedure: first add up the atomic masses of each atom in the molecule. \nC = 12.01 * 6 = 72.06\nH = 1.008 * 12 = 12.096\nO = 16 * 6 = 96\nfor a total of 180.156 atomic mass units in the whole molecule. That means that 180.156 grams would be exacly one mole, and we want to know how many moles in exactly 180 grams. So the answer is just a bit less than one mole, or 180 / 180.156, or .999134 moles.
165571
First you should draw the Lewis structure.\n\nBr\n|\nC=O\n|\nBr\n\nThere are 3 lone pairs of electrons on each bromine and two lone pairs on the oxygen.\n\nVSEPR tells us that the molecule is trigonal planar and the oxygen is a bit more electronegative than the bromine, therefore this molecule is polar.\n\nTake care,\nDavid Roth
1040448
ask your chem prof or tutor ..it's hard to explain over the internet!
295137
There are several forms of such microscopy, although they all have strengths and weaknesses.\n\nLight microscopy simply cannot see atoms and molecules. The wavelength of light is much longer than most molecules, making it impossible for a light microscope to resolve molecular detail.\n\nAtomic force microscopy moves a cantilever probe across a surface. It can't tell you anything about the shape or structure of individual atoms or molecules on that surface, but it can detect raised areas and indentations on the surface. It is very sensitive, and it can detect an elevation or depression the thickness of a single molecule.\n\nThere are several flavors of electron microscopy, but the one you might be interested in in Scanning Tunnelling Microscopy (STM). STM can basically "see" individual atoms, and they can even move atoms around one at a time. The problem with STM is that only certain types of materials can be examined (it works best with things like metals), making it very useful in material science but somewhat less useful in other areas of chemisty. \n\nThe way most chemists actually look at the structure of molecules on a daily basis is by Nuclear Magnetic Resonance (NMR) spectroscopy. While it technically isn't microscopy, NMR provides important information about how atoms are connected within a molecule. It is probably the most common way chemists determine the shape and structure of a molecule.\n\nAnother important technique (again not technically microscopy) is single crystal X-ray diffraction. This technique gives you an exact picture of your molecule, and works even with large molecules like proteins that are difficult to analyze by NMR. The drawback to single crystal X-ray diffraction is that you need to grow a crytal of your compound, and this can sometimes be very difficult.\n\nThere are a few other techniques out there, but these are the major ones. Hope this helps!