Bond Definition and 324 Threads

Hello I have come across this inexplicable fact mentioned in somewhere that for a chain of S = 1 spins, the adjacent bonds can all be in a singlet state i.e. singlets can be shared in this case (forming valence bond solids) but not, for example, for |S| = 1/2, the latter point being clear. I...

Duke has been "Velcro Dog" for over a year since we adopted him from a shelter. Tonight was the first time that he has spent the night in the bedroom without me. He is always stuck to me like a burr. Last night, my wife and I spent the evening (New Year's Eve) playing cribbage, dominoes...

Click http://www.xtremepapers.net/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s02_qp_1.pdf" for question. Question 33. The atomic Radii of Iodine is much larger than Chlorine hence the bond length of HI should be smaller compared to HCl. Apparently, it is not so...

Can someone tell me the role of 'free' electrons in a metallic bond? i've answered below here... am i right? and if there is detailed explanation? my answer : Solid metal are therefore visualized as consisting on positive-ion cores (atoms without their valence electrons) and of valence...

And how does it make metals better conductors? Is it because the free electrons move charges around better than things with electrons bound to the nucleus better?

Hydrogen has one valence electron, Chlorine has 7. Chlorine only needs one to become stable, and hydrogen wants to get rid of its only one. When they come in contact, shouldn't they react and form HCl, but held together by ionic bonds?

Homework Statement Another chemistry question :D Arrange the following AFn species in order of increasing F-A-F bond angles: BeF3, BeF2, CF44, NF3, and OF2.Homework Equations The Attempt at a Solution Ok so I'm thinking that it would be OF2 first because it's bent and both of the lone pairs...

Homework Statement Predict the actual bond angle in SeCl2 using the VSEPR theory. a. more than 120° b. between 109° and 120° c. between 90° and 109° d. less than 109° Homework Equations The Attempt at a Solution So I tried to draw the Lewis Structure of the chemical and then...

Can anyone explain to me how you calculate bond length? Thanks!

Homework Statement Why are all the carbon-carbon bonds are the same length rather than alternating lengths? all help appreciated :) Homework Equations The Attempt at a Solution I researched it and all i discovered is that each bond length is the same in Benzene, but i never found...

Homework Statement C25H52 reacts in a combustion reaction. Calculate Bond EnergyHomework Equations The Attempt at a Solution the balanced equation would be C25H52 + 38O2 = 25CO2 + 26H2O 38 o=o bonds + 50 c-o bonds + 52 h-o...

Hello PFers, a chemistry question that I need help with awaits! Homework Statement 10.42 Describe the types of bonds and orbitals in the following: (a) NO3-; (b) CS2; (c) CH2O; (d) FNO; (e) C2F4. Homework Equations The Attempt at a Solution I tried to visualize the kind of...

Homework Statement The values of standard enthalpy of formation of SF6(g), S(g), F(g) are -1100, 275, 80 kJ/mol resp. What is the average S-F bond enthalpy in SF6? Homework Equations The Attempt at a Solution I read that the bond enthalpy is negative of enthalpy of formation from...

Stronger bond= lower energy? why? "In an exothermic reaction, some of the potential energy stored in the chemical bonds is being converted to thermal energy via kinetic energy(heat) In this exothermic process, the bonds in the products are stronger than those of the reactants." This does not...

I often hear that metals and nonmetals can only form ionic bonds, but is this true when difference in electronegativity between the atoms is low? Shouldn't they be able to form polor covalent and nonpolar covalent bonds? Or do the electronegativity based predictions fail in these cases?

Homework Statement A $500, 8% bond is purchased on Feb 1, 2004 to yield 10% compounded semiannually. The interest on the bond is payable on Feb 1 and Aug 1 each year. Find the purchase price if the bond is redeemable at face value on Feb 1, 2014. Homework Equations The Attempt at...

I had a question in a lab about which elements are least likely to form polar covalent bonds with hydrogen. From what I understand, what governs how polar a bond is, is the electronegativity of the element. The answer said that Carbon was the one which was least likely to form the bond, but...

Dear all: I wonder how the adhesion between Al and Au is. I am going to deposit Au on top of Al layer. Regards.

Homework Statement Given that the total cohesive energy, U, in an ionic crystal as a function of nearest neighbor distance, R, between two ions +e and -e is given by: U(R) = \frac{A}{R^n} - \frac{\alpha e^2}{4 \pi \epsilon R} show that at equilibrium: U(R) = \frac{\alpha e^2}{4 \pi...

N-F C-F H-F O-F would it be H-F since the difference between the their electronegativities is the greatest?

Can someone explain to me the fundamental understanding of why, when two hydrogen atoms for example, release energy when they form a covalent bond? I can't seem to comprehend. Here is my reasoning, please see if this makes any sense of I am simply going in the wrong direction, I would really...

Hi, Im doing an IB Extended essay on astrophysics, on the planning stage. My aim is to calculate the surface temperature of an extrasolar planet. I have most of the caculations done, but I am stuck on just one part - calculating the Bond albedo of the planet. I know what the geometric albedo...

I'm just wondering why it's important for atomic structures to contain protons. Hydrogen-3 has two neutrons and one proton. Could you have a particle with two or more neutrons held together by nothing but the strong nuclear force? Is the reason I don't know about this because such particles...

Hi. i don't know a lot about chemistry so bear with me. the bond is between a member of the carboxyl group and the amino acid lysine. as i understand i need an enzyme. what readily available enzyme would suffice? would protease work?

Homework Statement What is the bond order of B22- Homework Equations (Number of bonding electrons - number of antibonding electron)/2 The Attempt at a Solution (3-0)/2 = 1.5, which is wrong. What's going on?

Homework Statement One mole of iron (6 *10^23 atoms) has a mass of 56 grams, and its density is 7.87 grams per cubic centimeter, so the center-to-center distance between atoms is 2.28 *10-10 m. You have a long thin bar of iron, 2.9 m long, with a square cross section, 0.05 cm on a side...

What is a quoted price of a bond? Is it a clean price? I think it is the present value of the face value of a bond, am I correct? What is the quoted price of a bond that has 4.5 years until maturity? The face value of the bond is $5,000 and it has a coupon rate of 8.1% compounded...

Can anyone give me some insight into any materials/substances that might bond to calcium fluoride (CaF2)? Any help is appreciated, thanks.

[b]1. The equilibrium bond length of the He dimer is 2.97 angstroms. What is the binding energy in kJ/mol for this dimer? Would be dimer be stable at room temperature T= 300K (Hint: compare the binding energy to kT) [b]2. interaction potential for the dimer: V(r) =...

Nitrogen double bonded with Oxygen... I can't find the bond enthalpy for it ANYWHERE, please help :(

Hi all members, I have some problems with my assignment here. I would like to confirm on something on SEXAFS (surface extended x-ray adsorption fine structure) such as to determine the bond length of near neighboring atom and geometry of it. But I do not have a clear idea on how to get the bond...

Bond angle in methane? Have been doing for 1 hr! Homework Statement In the methane molecule, CH4, each hydrogen atom is at a corner of a regular tetrahedron with the carbon atom at the center. In coordinates where one of the C-H bonds is in the direction of i + j + k, an adjacent C-H bond is...

I am having trouble identifying the difference between VB theory and molecular orbital theory. To me, they seem to be one and the same. In VB theory, two atomic orbitals overlap and share electrons forming a bond... Wouldn't this combination of two Atomic orbitals make a molecular orbital?

its being said, " more the loss of energy, more the strength of the covalent bond" revered members, could u explain why? thanks in advance

Homework Statement Show that the bond length for sodium chloride is 0.28nm given that it has a relative density of 2.2, sodium has an atomic weight of 23, and chlorine 35.5. Avogadro's number is 6.0x10^23 Homework Equations The Attempt at a Solution I've tried many things but...

Can someone please tell me why the heads of the big Wall Street bond rating agencies haven't been charged yet? I don't even know if they're being investigated. We hear a lot about AIG and the banks, but not a lot about outfits like Moody's. I've called news organizations and I don't get good...

Does an atom ALWAYS need to be hybridized in order for it to bond to other atoms? Why or why not? In what cases does it need to be hybridized in order to bond with other atoms?

I just watched Casino Royal and Quantum of Solace again in chronological order and had a revelation. The first time I saw Casino Royal shortly after it was released I didn't think much of it. A year or what ever later I then saw Quantum of Solace and thought it was pretty boring. I recently...

Hi, first time poster. Quick question: Why is the bond energy for a bond that contains a more highly substituted (tertiary) carbon weaker than the bond energy of a bond that contains a less substituted (primary) carbon? Let me clarify with an example. Say Bond A is a single bond between a...

Hello. I am currently a freshman in college and finding the chapter on Quantum Mechanics incredibly interesting. Whether I decide to delve into this field is still up in the air, but I am having trouble fully understanding the concepts behind Molecular Orbital Theory and how it relates to the...

Hi there. I'm new to the forums, a freshman in college, and mainly asking this for the sake of understanding. Why does the MO theory cause lone pairs to bond? For example, in the Lewis sturcture of O2 there are 2 pairs of unbonded lone pair electrons which makes sense since both oxygen atoms...

Homework Statement Look at the diagram accompanying the question. Which has least C-H bond energy? The Attempt at a Solution On cleavage of a C-H bond, a carbanion is formed as carbon is more electronegative than hydrogen. So cleavage of (b) results in a carbanion stabilized by resonance

Question Details: Is CO paramagnetic or diamagnetic? i put diamagnetic because there are no lone paris is that corrects? and If CO gained one election, becoming CO^-, would the bond become weaker or stronger? i believe that the bond would become weaker since there is one lone pari and it...

Not sure where this goes, but here goes: Water O-H bond is usually thought of as 0.942 angstrom when looked at as H2O molecules. This very nice site on water http://www.lsbu.ac.uk/water/evidnc.html suggests that x-ray data O···H peaks at 1.85 Å and 3.3 Å with no peak less then 1.85...

Hi PF members, Is there any good glue/adhesive to bond a 30 micrometer kapton foil to copper metal... The bonding should be strong enough to withstand liquid helium temperature (my working condition is 4.2 K to room temperature)...I can cure only at room temperature. or anyone have some...

Br=2.8 P=2.1 i know that we should subtract them but my formula is: PBr_3 and how to know if its a yonic bond dipolar bond or covalent bond ??

Fe=[Ar]3p^6 4s^2 it needs to give 7 electrons to become neutral. S=[Ne]3S^2 3p^4 it needs to take 2 electrons to become neutral.how to describe Fe_2 S_3 ??

http://img525.imageshack.us/img525/2290/84419342em1.th.gif in case A: S has a bigger electonegative energy then Ca so it will "take" 2 electrons from Ca inorder to be a complete gas like (Ar) so i know why there is +2 on Ca and -2 on S . Ca has after perfect gas 4S^2 S...

For fun I showed this to my parents. They don't have the guts to play spreads. I have no money to invest so, tell me what you guys think. Why Short Long Bonds If my calculations are correct a drop in the 30 year treasury to 2% from 3.22% would result in 21.3% capital gain on a long...

Cl gets similar electronegativity as N, NH3 is a hydrogen bond, but HCl isn't, why? N and Cl also gets lone pair electrons! N and Cl is more or less the same. Could anybody please answer this question? Okay, if I rephrase it, it will become why the bonding between H and Cl isn't hydrogen...