Chemistry Weekly Newsletter - Monday, September 28, 2015

Top new questions this week: When can a molecule be considered freely rotating at room temperature? This question sparked from a long discussion in chat about the nature of $\ce{H2O2}$ and whether that molecule can be considered to rotate around the $\ce{O-O}$ axis (and hence display axial ... physical-chemistry temperature conformers   asked by Jan 16 votes answered by Curt F. 14 votes Why are the C-C bonds in benzene closer in length to double bonds than single bonds? The $\ce{C-C}$ bonds in benzene are $\mathrm{140~pm}$ long which puts them in between single bonds and double bonds (given at $\mathrm{147-154~pm}$ and $\ce{134-135~pm}$ respectively, sourced from ... organic-chemistry bond aromatic-compounds resonance   asked by bon 14 votes answered by permeakra 9 votes What does the "h" "k" and "(5.2.2.02,6)" mean in Dibenzo(h,k)-4-oxatricyclo(5.2.2.02,6)undec-8,10- diene-3, 5-dione I am preparing to do an experiment that involves synthesizing Dibenzo(h,k)-4-oxatricyclo(5.2.2.02,6)undec-8,10- diene-3, 5-dione via a Diels-Alder reaction. Could someone please explain the ... organic-chemistry nomenclature synthesis   asked by liya77 5 votes answered by Loong 4 votes Oxalate ion dentiticity - why is it bidentate and not tetradentate? Why is the oxalate ion a bidentate ligand? Why does it not act like a tetradentate ligand (having four oxygen atoms, with lone pairs)? coordination-compounds   asked by Abhirikshma 4 votes answered by Ben Norris 8 votes Hill system with isotopologue I'd like to use Hill notation (i.e. CH, then alphabetical), but I am not sure how to include isotopologues (i.e. carbon-13) in this notation. For example, what would be the preferred form of ... notation   asked by ngreen08 4 votes answered by Curt F. 1 vote Hybrization of H in HNO There is a problem that states: Find the molecular geometry of each molecule and the hybridization of each atom in the molecule. The two molecules are HNO and HCN. I found HNO to be sp3 hybridized and ... orbitals hybridization   asked by user21310 4 votes answered by user232083 2 votes Why does tea dissolve better when put in water rather than milk? I sometimes drink tea with or without milk. What I have noticed is that when I dip the bag in water the tea spreads out evenly and I have a cup of tea in like 5 minutes. But when I do the same with ... everyday-chemistry food-chemistry mixtures   asked by Anarach 4 votes answered by Greg 6 votes Greatest hits from previous weeks: reason for the stronger acidic property of phenol than alcohol "In phenol, pulling the $p_z$ electrons from the oxygen atom into the ring causes the hydrogen atom to be more partially positive than it is in aliphatic alcohols. This means it is much more easily ... acid-base aromatic-compounds   asked by Eliza 11 votes answered by G M 10 votes Different reactions of clean and rusty iron nails in vinegar (acetic acid) I have submerged a iron nail in vinegar twice recently. What is puzzling me is the different results each time. The first time I submerged it, it was covered in rust. When I put it in the solution of ... home-experiment hydrogen   asked by user2514631 3 votes answered by kaliaden 3 votes Can you answer these? What is the justification for Ligand Close Packing Model? The LCP model predicts that nonbonded atom to atom distances remain approximately the same when the central atoms are changed. What is the theoretical justification for this? thanks theoretical-chemistry molecular-structure   asked by CognisMantis 1 vote Binary phase transition boiling rate (Callen 9.7-2) The phase diagram of a solution of A in B, at a pressure of 1 atm, has a coexistence region in the $(X,T)$ plane (e.g., $X_A$ is a liquid molar fraction with $N=N_A+N_B$ and T ... physical-chemistry thermodynamics   asked by NSERC Protester 1 vote Internal Energy Constant Volume and Constant Pressure What is the internal energy when a reaction is run at constant volume and $9.19\ \mathrm{kJ}$ of heat is absorbed, when run at constant pressure $8.62\ \mathrm{kJ}$ is absorbed? I know that internal ... homework thermodynamics   asked by Jake 1 vote

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