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Topic: Dipole dipole attractions

	Dipole - Wikipedia, the free encyclopedia
		A dipole (Greek: dyo = two and polos = pivot) is a pair of electric charges or magnetic poles of equal magnitude but opposite polarity (opposite electronic charges), separated by some (usually small) distance.
		Dipoles can be characterized by their dipole moment, a vector quantity with a magnitude equal to the product of the charge or magnetic strength of one of the poles and the distance separating the two poles.
		The field of a point dipole has a particularly simple form, and the order-1 term in the multipole expansion is precisely the point dipole field.
	www.wikipedia.org /wiki/Dipole (939 words)

	Dipole (Site not responding. Last check: 2007-10-20)
		From the point of view of the mathematics of distributions, a dipole can be taken to be the directional derivative of a Dirac delta function.
		A dipole is a pair of electric charges or magnetic poles of equal magnitude but opposite polarity, separated by some (usually small) distance.
		The direction of the dipole moment corresponds to the direction from the negative to the positive charge or from the south to the north pole.
	www.sciencedaily.com /encyclopedia/dipole (569 words)

	Dipole -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-20)
		Dipoles can be characterized by their dipole (A particular point in time) moment, a vector quantity with a magnitude equal to the product of the charge or magnetic strength of one of the poles and the distance separating the two poles.
		The direction of the dipole moment corresponds to the direction from the negative to the positive charge or from the (The region of the United States lying south of the Mason-Dixon Line) south to the (The northernmost point of the Earth's axis) north pole.
		Instantaneous dipoles: These occur due to chance when (An elementary particle with negative charge) electrons happen to be more concentrated in one place than another in a ((physics and chemistry) the simplest structural unit of an element or compound) molecule, creating a temporary dipole.
	www.absoluteastronomy.com /encyclopedia/d/di/dipole.htm (986 words)

	Dipole moment (Site not responding. Last check: 2007-10-20)
		A dipole is a pair of electric charges ormagnetic poles of equal magnitude but opposite polarity, separated by some (usually small) distance.
		Dipoles can be characterizedby their dipole moment, a vector quantity with a magnitude equal tothe product of the charge or magnetic strength of one of the poles and the distance separating the two poles.
		The direction ofthe dipole moment corresponds to the direction from the negative to the positive charge or from the south to the north pole.
	www.therfcc.org /dipole-moment-81844.html (432 words)

	Dipole (Site not responding. Last check: 2007-10-20)
		From the point of view of the mathematics of distribution s, a dipole can be taken to be the directional derivative of a Dirac delta function.
		Levitated Dipole Experiment Device to expore the physics of plasma confinement in a magnetic dipole field.
		Dipole AntiGravity Introduction of a new physical theory of anti-gravity.
	www.serebella.com /encyclopedia/article-Dipole.html (730 words)

	Dipole - Wikipedia
		A dipole is a pair of electric charges or magnetic poles of equal magnitude but opposite polarity, separated by some distance.
		Strictly speaking a dipole contains only two point charges (or magnetic poles), however various arrangements of multiple charges have dipole moments and may be treated as an effective dipole.
		A molecule with a permanent dipole moment is said to be polarised.
	nostalgia.wikipedia.org /wiki/Dipole (364 words)

	Encyclopedia: Dipole (Site not responding. Last check: 2007-10-20)
		When placed in an electric (E) or magnetic (B) field, equal but opposite forces arise on each side of the dipole creating a torque Ï: In physics, an electric field or E-field is an effect produced by an electric charge that exerts a force on charged objects in its vicinity.
		In physics, magnetic monopole is a term describing a hypothetical particle that could be quickly clarified to a person familiar with magnets but not electromagnetic theory as a magnet with only one pole.
		Electronegativity is the measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond.
	www.nationmaster.com /encyclopedia/Dipole (1545 words)

	Dipole (Site not responding. Last check: 2007-10-20)
		A dipole is a pair of electric charges or magnetic poles of equal magnitude opposite polarity separated by some (usually small) Dipoles can be characterized by their dipole moment a vector quantity with a magnitude to the product of the charge or strength of one of the poles and distance separating the two poles.
		Other more complicated can be approximated as dipole systems mathematically if the net charge is zero but positive and negative charges are not distributed and the dipole field structure is the one.
		The physical chemist Peter J. Debye was the first scientist to study dipoles extensively and dipole moments are consequently in units named debyes in his honor.
	www.freeglossary.com /Magnetic_dipole (511 words)

	Dipole (Site not responding. Last check: 2007-10-20)
		A dipole is also a type of radio antenna.'' Spherical dipoleA dipole (Greek: dyo = two and polos = pivot) is a pair of electric charges or magnetic poles of equal magnitude but opposite polarity (opposite electronic charges), separated by some (usually small) distance.
		This is simply one term in the multipole expansion; when the charge ("monopole moment") is 0 — as it always is for the magnetic case, since there are no magnetic monopoles — the dipole term is the dominant one at large distances: it falls off in proportion to 1/r
		For example: (positive) H-Cl (negative) A molecule with a permanent dipole moment is called a polar molecule and is polarized.
	dipole.ask.dyndns.dk (758 words)

	Dipole (Site not responding. Last check: 2007-10-20)
		Operating in the 2.4GHz to 2.5GHz and the 5.15GHz to 5.85GHz bands, the dipole antennas have 50ohm impedance and are RoHS-compliant.
		The unit cells of pyroelectric materials have a dipole moment.
		The dipole moment per unit volume of the material is called the spontaneous polarization PS.
	www.wikiverse.org /dipole (634 words)

	Dipole mathematics distribution Dirac delta function dipole north pole electric magnetic monopole electrons metre radian (Site not responding. Last check: 2007-10-20)
		» Instantaneous dipoles: These occur due to chance when electrons happen to be more concentrated in one place than another in a molecule, creating a temporary dipole.
		are as above:p is the (vector) dipole moment:ε
		Therefore, when placed in a magnetic field, a magnetic dipole tends to align itself in opposed polarity to that field, thereby canceling the net field strength...
	en.powerwissen.com /Xf3CsPrtUkZerk%2BbRAyARA%3D%3D_Dipole.html (935 words)

	London Forces
		Experiments have shown, though, that the actual strengths of the attractions between polar molecules are greater than we would predict from the polarity of the isolated molecules.
		The additional attraction is the result of London forces, which contribute to the attractions between polar molecules as well as nonpolar ones.
		The increased attractions between polar molecules that come from the higher charges that arise due to instantaneous increases in dipoles and induced increases in dipoles are London forces.
	www.mpcfaculty.net /mark_bishop/London_polar_molecules.htm (441 words)

	Learning Objectives (Site not responding. Last check: 2007-10-20)
		The dipoles in a water molecule give the hydrogen atoms some positive character and the oxygen atom some negative character.
		However, dipole-dipole attractions are fairly weak and would not account for the strong interaction that is observed between water molecules.
		There is another, even stronger, attraction between water molecules that explains the unique character of water.
	chemistry.boisestate.edu /rbanks/inorganic/physical%20states/physical_states.htm (1451 words)

	Example 2
		The ketone 2-heptanone is a polar molecular compound with dipole-dipole attractions between the molecules.
		Stronger attractions lead to a lower equilibrium vapor pressure and a higher normal boiling point temperature.
		For molecules of about the same size, dipole-dipole attractions are stronger than London forces, so we expect acrolein to have a lower equilibrium vapor pressure and a higher normal boiling point temperature than butane.
	www.mpcfaculty.net /mark_bishop/attraction_strengths_bp_example.htm (309 words)

	an introduction to nitriles
		The nitrogen is very electronegative and the electrons in the triple bond are very easily pulled towards the nitrogen end of the bond.
		Nitriles therefore have strong permanent dipole-dipole attractions as well as van der Waals dispersion forces between their molecules.
		One of the slightly positive hydrogen atoms in a water molecule is attracted to the lone pair on the nitrogen atom in a nitrile and a hydrogen bond is formed.
	www.chemguide.co.uk /organicprops/nitriles/background.html (461 words)

	intermolecular bonding - van der Waals forces
		Intermolecular attractions are attractions between one molecule and a neighbouring molecule.
		In hydrogen's case the attractions are so weak that the molecules have to be cooled to 21 K (-252°C) before the attractions are enough to condense the hydrogen as a liquid.
		Surprisingly dipole-dipole attractions are fairly minor compared with dispersion forces, and their effect can only really be seen if you compare two molecules with the same number of electrons and the same size.
	www.chemguide.co.uk /atoms/bonding/vdw.html (1436 words)

	Dipole-dipole interactions (Site not responding. Last check: 2007-10-20)
		Molecules with permanent dipoles (polar molecules), attract each other, this pushes up the boiling points.
		In a cloud of molecules which aren't polar, as they move around due to diffusion, there will be very small changes in the electric fields as the molecules experience slight attractions and repulsions.
		The greater the number of electrons in a molecules the stronger these forces become, this explains why the boiling point increases with atomic mass in the alkanes and Group VII.
	www.webchem.net /notes/chemical_bonding/dipoledipole.htm (86 words)

	Dipole-Dipole Interactions (Site not responding. Last check: 2007-10-20)
		The Dipole-dipole force then arises from the attraction between the slightly positive end of one molecule and the slightly negative end of another.
		For figures illustrating the importance of shape on molecular dipoles, click here for CO and SO, and here for tetrahedral compounds such as carbon tetrachloride and chloroform, and here for water and ammonia.
		Again, setting a covalent bond as 100, the polar forces may be as much as 1, or 1% as strong as the bond that holds the atoms together in the molecule.
	neon.chem.uidaho.edu /%7Ehonors/dipole.html (332 words)

	Study Sheet
		You are asked to predict the relative strengths of attractions between particles of two substances, or you are asked a question that cannot be answered unless you know those relative strengths.
		If the distribution of polar bonds is symmetrical and their dipoles equal, the molecules are nonpolar and London forces are broken when they boil.
		If the distribution of polar bonds is asymmetrical, or symmetrical with unequal dipoles, the molecules are polar and dipole-dipole attractions enhanced by London forces are broken when they boil.
	www.mpcfaculty.net /mark_bishop/attraction_strengths_study_sheet.htm (470 words)

	Boiling Point Project (Site not responding. Last check: 2007-10-20)
		Also, because oxygen is more electronegative than carbon, the bonding electrons are not shared equally which produces a large dipole moment in the carbonyl group.
		Aldehydes are defined as compounds having one alkyl or aryl group and one hydrogen bonded to a carbon atom.
		The polarization in the carbonyl group creates intermolecular dipole-dipole attractions, resulting in higher boiling points than for hydrocarbons and ethers of similar molecular weights.
	www.sas.upenn.edu /~jmwolfe/bpp.html (403 words)

	Intermolecular force (Site not responding. Last check: 2007-10-20)
		Hydrogen bonds are also the intermolecular force that bind together the two strands in a molecule of DNA.
		Dipole-dipole interactions, also called Keesom interactions after Willem Hendrik Keesom who produced the first mathematical description in 1921, are the forces that occur between two molecules with permanent dipoles.
		Also called London forces or Van der Waals forces, these involve the attraction between temporarily induced dipoles in nonpolar molecules.
	www.sciencedaily.com /encyclopedia/intermolecular_force (332 words)

	TPOS - Propagation (Site not responding. Last check: 2007-10-20)
		The purpose of this lab is to find the effect of intermolecular forces on the transmission of sound.
		The molecule may be polar but sometimes the charge can shift to one side and cause London dispersion forces thus creating an attraction.
		Hydrogen bond: an extra strong dipole-dipole attraction between a hydrogen bound covalently to nitrogen, oxygen, or fluorine and another nitrogen, oxygen, or fluorine atom.
	www.alumni.ca /%7Ezhan4m1/propback.htm (163 words)

	an introduction to aryl halides (halogenoarenes)
		The main attractions between the molecules will be van der Waals dispersion forces.
		There will also be permanent dipole-dipole attractions involved in the chlorobenzene and bromobenzene, but very little in the iodobenzene.
		These dipole-dipole attractions must be very unimportant relative to the dispersion forces because the most polar molecule (the chlorobenzene) has the lowest boiling point of the three.
	www.chemguide.co.uk /organicprops/arylhalides/background.html (545 words)

	The Student Room - View Single Post - A Level Organic Chemistry Questions!
		The result is that the dipole moment of the O-H bond is very big: so much so that very strong permanent dipole-dipole attractions (called hydrogen bonding) can occur between -OH groups.
		Finally the thioether has the smallest net dipole moment, but the largest carbon skeleton: thus the greatest intermolecular van der Waals attractions.
		Although the dipole moment of the B-F bond is greater than the N-F bond, the BF3 molecule is trigonal planar in shape and so has NO net dipole moment.
	www.thestudentroom.co.uk /showpost.php?p=1782370&postcount=2 (230 words)

	Home
		Adjacent chains are held together by the attraction of oppositely charged dipoles.
		Thermosetting plastics tend to be hard and rigid, and do not soften due to their tight-meshed, branched structure.
		Therefore when manufacturing thermosetting-plastic components it is important to achieve the required, otherwise the shape becomes waste and cannot be reused.
	people.bath.ac.uk /en3hmt (249 words)

	London Dispersion Forces (Site not responding. Last check: 2007-10-20)
		London forces are the attractive forces that cause nonpolar substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently.
		Because of the constant motion of the electrons, an atom or molecule can develop a temporary (instantaneous) dipole when its electrons are distributed unsymmetrically about the nucleus.
		A second atom or molecule, in turn, can be distorted by the appearance of the dipole in the first atom or molecule (because electrons repel one another) which leads to an electrostatic attraction between the two atoms or molecules.
	www.chem.purdue.edu /gchelp/liquids/disperse.html (336 words)

	intermolecular bonding - hydrogen bonds
		Although for the most part the trend is exactly the same as in group 4 (for exactly the same reasons), the boiling point of the hydride of the first element in each group is abnormally high.
		Hydrogen bonds have about a tenth of the strength of an average covalent bond, and are being constantly broken and reformed in liquid water.
		The van der Waals attractions (both dispersion forces and dipole-dipole attractions) in each will be much the same.
	www.chemguide.co.uk /atoms/bonding/hbond.html (1180 words)

	Dipole-dipole attractions (Site not responding. Last check: 2007-10-20)
		The attraction of the positive ends of polar molecules by the negative ends of other polar molecules.
		Hydrogen bonding is an example of a dipole - dipole interaction in which a hydrogen atom acts as a “bridge” between two very electronegative atoms.
		Ethane and methanol have similar molecular weights but C2H6 is a gas at room temperature and CH3OH is a liquid.
	www.fsj.ualberta.ca /chimie/chem161/BINTRO_E/sld070.htm (77 words)

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