Search found 20 matches

by dstemp
Thu Dec 07, 2017 7:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic v. Exothermic Reactions
Replies: 9
Views: 836

Re: Endothermic v. Exothermic Reactions

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?
by dstemp
Wed Dec 06, 2017 8:40 pm
Forum: Sigma & Pi Bonds
Topic: Delocalized Pi-Bonding
Replies: 5
Views: 390

Re: Delocalized Pi-Bonding

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?
by dstemp
Sun Dec 03, 2017 11:06 pm
Forum: Lewis Structures
Topic: Midterm Question: Lewis Structure for HOCO [ENDORSED]
Replies: 6
Views: 636

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

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,...
by dstemp
Sat Dec 02, 2017 6:05 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: HW: 12.49
Replies: 1
Views: 138

HW: 12.49

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....
by dstemp
Sat Dec 02, 2017 5:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Question 12.19
Replies: 3
Views: 297

Re: Question 12.19

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?
by dstemp
Sat Dec 02, 2017 5:54 pm
Forum: Amphoteric Compounds
Topic: 12.17 [ENDORSED]
Replies: 9
Views: 810

Re: 12.17 [ENDORSED]

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?
by dstemp
Mon Nov 27, 2017 10:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment Chemical Equilibrium Part 2 #29 [ENDORSED]
Replies: 6
Views: 379

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

Why don't you just take the difference of 1.84x10^-4 - 3.36x10^-5 ? Why is there a 2x involved?
by dstemp
Mon Nov 27, 2017 8:44 pm
Forum: Naming
Topic: Problem 17.31 d [ENDORSED]
Replies: 3
Views: 200

Re: Problem 17.31 d [ENDORSED]

On a separate note, why is diaqua enclosed in parentheses? What does this signify?
by dstemp
Fri Nov 17, 2017 12:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.25 lewis structure
Replies: 4
Views: 187

Re: 4.25 lewis structure

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?
by dstemp
Fri Nov 17, 2017 12:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.33
Replies: 2
Views: 128

4.33

When writing out the hybridization of an atom, when is it necessary to include a coefficient? I.e. sp^3 vs. 2sp^3
by dstemp
Wed Nov 08, 2017 11:47 pm
Forum: Ionic & Covalent Bonds
Topic: Polar vs. Non-polar
Replies: 7
Views: 344

Re: Polar vs. Non-polar

This isn't always true though. For example H20 has the same outer atoms and appears symmetric, but is actually very polar.
by dstemp
Wed Nov 08, 2017 11:31 pm
Forum: Ionic & Covalent Bonds
Topic: Polar vs. Non-polar
Replies: 7
Views: 344

Re: Polar vs. Non-polar

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.
by dstemp
Tue Nov 07, 2017 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Beryllium Octet Rule
Replies: 6
Views: 986

Re: Beryllium Octet Rule

Then why does Boron in BF3 not have a full octet either?
by dstemp
Fri Nov 03, 2017 2:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Only certain central atoms have a full octet?
Replies: 4
Views: 278

Only certain central atoms have a full octet?

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...
by dstemp
Tue Oct 31, 2017 10:40 am
Forum: Trends in The Periodic Table
Topic: electron shielding 2.37(c) [ENDORSED]
Replies: 3
Views: 237

Re: electron shielding 2.37(c) [ENDORSED]

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?
by dstemp
Tue Oct 31, 2017 10:34 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Difference Between Orbitals and Subshells [ENDORSED]
Replies: 7
Views: 572

Re: Difference Between Orbitals and Subshells [ENDORSED]

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?
by dstemp
Mon Oct 16, 2017 10:49 pm
Forum: Photoelectric Effect
Topic: Post- Module Assessment #24
Replies: 3
Views: 171

Re: Post- Module Assessment #24

Thank you, that makes sense. Do you know why gamma rays wouldn't work then, since they have an even higher freq?
by dstemp
Mon Oct 16, 2017 10:28 pm
Forum: Photoelectric Effect
Topic: Post- Module Assessment #24
Replies: 3
Views: 171

Post- Module Assessment #24

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...
by dstemp
Mon Oct 16, 2017 9:55 am
Forum: Properties of Light
Topic: Chapter 1: Problem 9...Radiation from reading?
Replies: 3
Views: 207

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

Thank you, that makes perfect sense, and helps clarify the spectrum for me.
by dstemp
Sun Oct 08, 2017 9:35 pm
Forum: Properties of Light
Topic: Chapter 1: Problem 9...Radiation from reading?
Replies: 3
Views: 207

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

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?

Go to advanced search