CHEMISTRY COMMUNITY

dstemp

In my discussion section, the delta H for a reaction was -100.2 KJ/mol. My TA said that the negative sign means the reaction is exothermic (heat's produced) so the reaction shifts to the right. However, don't exothermic favor the formation of reactants? Could somebody please clarify this for me?

dstemp

So just to be clear, in order for there to be delocalized pi-bonding there must be at least a double bond between two atoms as well as a lone pair on one of the atoms?

dstemp

Why wouldn't it work to have carbon as the central atom with a single bond to an oxygen and hydrogen, and a double bond to the other oxygen (resonance)? Put 5e- on the single bonded oxygen (making it radical) and 4 e- on the double bonded oxygen. This would make a formal charge of zero on each atom,...

dstemp

Which is the stronger base, the hypobromite ion, BrO-, or morphine, C17H19O3N? Justify your answer. I understand that you would want to determine the pH of these bases in order to determine which is stronger, but in the solution manual it seems as though we should already know the pH of these bases....

dstemp

In the solution for this question is says : pH= -log(.12[HCl]/[HCl])=0.92 ..... I understand why you would want to use logs here, but why can't you just do -log(0.12[HCl])? Why is it necessary to divide by the concentration of HCl too?

dstemp

If metal oxides are basic, why is Bi2O3 amphoteric? Since Bismuth is a metal. Is the metal oxides being basic simply a general rule with certain exceptions?

dstemp

Why don't you just take the difference of 1.84x10^-4 - 3.36x10^-5 ? Why is there a 2x involved?

dstemp

On a separate note, why is diaqua enclosed in parentheses? What does this signify?

dstemp

In this problem, why isn't CH2Cl2 nonpolar? It seems like the dipole moments would cancel out. Do all of the outer atoms need to be the same for a molecule to be nonpolar?

dstemp

When writing out the hybridization of an atom, when is it necessary to include a coefficient? I.e. sp^3 vs. 2sp^3

dstemp

This isn't always true though. For example H20 has the same outer atoms and appears symmetric, but is actually very polar.

dstemp

I believe to determine if a molecule is polar or non-polar, it is only important to know the charges on the ends of the molecule and the difference in electronegativity between bonded atoms, since ionic bonds are pretty much guaranteed to be polar.

dstemp

Then why does Boron in BF3 not have a full octet either?

dstemp

In the lecture today, in a couple different molecules the central atom did not have a full octet. For example, in Beryllium Chloride BeCl2 and in BF3, the Beryllium and Boron only had four shared electrons and six shared electrons respectively. Why is this? Especially when there are enough lone pair...

dstemp

Doesn't electron shielding also affect the effective nuclear charge? If so, do you know what the trend is on the periodic table for effective nuclear charge?

dstemp

I know it is possible to determine what subshell an electron is in, but is it possible to determine the orbital it is in and the corresponding spin of the electron?

dstemp

Thank you, that makes sense. Do you know why gamma rays wouldn't work then, since they have an even higher freq?

dstemp

In photoelectric experiments, typically what part of the electromagnetic spectrum is the incoming light? Also, to better my understanding, why does the light typically lie in a specific part of the spectrum. For example, why can't visible light eject electrons? Is it because the wavelength in the vi...

dstemp

Thank you, that makes perfect sense, and helps clarify the spectrum for me.

dstemp

I was attempting to fill out the table, but I was unsure of what type of radiation would be involved with reading (x-ray, suntan, and microwave are all a little more straightforward). Would reading simply be in the "visible light" category?

CHEMISTRY COMMUNITY

Search found 20 matches

Re: Endothermic v. Exothermic Reactions

Re: Delocalized Pi-Bonding

Re: Midterm Question: Lewis Structure for HOCO [ENDORSED]

HW: 12.49

Re: Question 12.19

Re: 12.17 [ENDORSED]

Re: Post Assessment Chemical Equilibrium Part 2 #29 [ENDORSED]

Re: Problem 17.31 d [ENDORSED]

Re: 4.25 lewis structure

4.33

Re: Polar vs. Non-polar

Re: Polar vs. Non-polar

Re: Beryllium Octet Rule

Only certain central atoms have a full octet?

Re: electron shielding 2.37(c) [ENDORSED]

Re: Difference Between Orbitals and Subshells [ENDORSED]

Re: Post- Module Assessment #24

Post- Module Assessment #24

Re: Chapter 1: Problem 9...Radiation from reading?

Chapter 1: Problem 9...Radiation from reading?