Search found 27 matches

Sat Dec 09, 2017 12:51 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.55 (c) increasing acidity
Replies: 2
Views: 212

Re: 12.55 (c) increasing acidity

If you look at the Ka values for HCOOH vs. CH3COOH: HCOOH: 1.8 x 10^-4 CH3COOH: 1.8 x 10^-5 The Ka, or acid dissociation constant, is greater for HCOOH, meaning that the reaction shifts highly to the right, as more protons are getting dissociated from the compound as compared to the dissociation con...
Sat Dec 09, 2017 12:43 am
Forum: Bond Lengths & Energies
Topic: Bond Length and Bond Strength Relationship
Replies: 5
Views: 1178

Re: Bond Length and Bond Strength Relationship

Does the relationship between bond length and bond strength only apply for diatomic molecules (like HCl)? Or does it apply for all acids/bases? When do you apply the relationship between bond length and bond strength?
Sat Dec 09, 2017 12:41 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 290

Re: Bond Angles

Yes, I think we should know generally which shapes have which bond angles, and how the placement of lone pairs affects the bond angles. For example, tetrahedral shapes have bond angles of 109.5, but if there are lone pairs, the repulsion between the lone pairs and bonds causes the bonds to be pushed...
Thu Nov 30, 2017 7:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 11.7
Replies: 4
Views: 344

Re: Question 11.7

Can someone help me out with part C of 11.7, I don’t really understand why the answer book is out of 17? 17 is the total number of diatomic reactants and monoatomic products there are in the final flask. So, in the equation for solving for K: K = (X^2)/(X2) = ((12/17) x 0.10)^2/((7/17) x 0.10), whe...
Thu Nov 30, 2017 6:57 pm
Forum: Student Social/Study Group
Topic: Naming Complexes
Replies: 6
Views: 1124

Re: Naming Complexes

Can someone please explain how to name compounds (with an example) that would include the bis-, tris-, or tetrakis-? I don't really understand when that would apply to a complex. Also for the charges, does the overall charge of a complex have any affect on the oxidation number put in the name of th...
Sun Nov 26, 2017 8:48 pm
Forum: Hybridization
Topic: HMK 4.91
Replies: 3
Views: 272

HMK 4.91

This problem asks to draw the Lewis structure of benzyne (C6H4) using two double bonds and a triple bond, which I did, but then asks us to explain why this molecule is highly reactive. Could someone please explain why it would be highly reactive? Thank you!
Fri Nov 24, 2017 4:27 pm
Forum: Ideal Gases
Topic: Kp and Kc
Replies: 7
Views: 684

Re: Kp and Kc

While this is not a difference, also keep in mind that you calculate both of them the same way, with the products on the top and the reactants on the bottom!
Fri Nov 24, 2017 4:23 pm
Forum: Dipole Moments
Topic: Dipole arrows
Replies: 2
Views: 283

Re: Dipole arrows

We've also been drawing them from the positive to negative charge in discussion--I would just draw it like that on the test!
Fri Nov 17, 2017 11:33 am
Forum: Hybridization
Topic: Filling the hybrid orbitals?
Replies: 12
Views: 854

Re: Filling the hybrid orbitals?

I am not sure if this is what you're asking, but when I draw hybridization orbitals, I normally start by drawing the electrons in their appropriate (s or p) orbitals at their ground state (first fill the s orbital, then fill the p orbital with electrons that have a parallel spin before pairing them,...
Fri Nov 17, 2017 11:23 am
Forum: Hybridization
Topic: Coordination sphere
Replies: 3
Views: 310

Re: Coordination sphere

As shown on the slide during lecture, the coordination sphere contains the central metal atom, all of its ligands (which are directly bound to the central metal atom), and the bonds between the central atom and the ligand. Anything that is outside of the coordination sphere is not directly bound to ...
Fri Nov 10, 2017 6:24 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: More Polarizable/Polarizing Power
Replies: 6
Views: 461

Re: More Polarizable/Polarizing Power

bigger anions have higher polarizability and cations with greater charge have higher polarizing power correct? Or is it the other way around One if the UAs explained this way and it made sense to me: the smaller the cation, the more polarizing power because it’s better able to distort the anion. On...
Fri Nov 10, 2017 6:07 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polar vs nonpolar vs ionic
Replies: 11
Views: 7859

Re: Polar vs nonpolar vs ionic

Laura Riccardelli wrote:Is a N2 molecule covalent?

You can also think of it as: since the same atom is bonded to itself, their electronegativities are the same, and they both share the electrons equally.
Wed Nov 08, 2017 9:43 pm
Forum: Lewis Structures
Topic: Isolobal Principle
Replies: 1
Views: 205

Isolobal Principle

For the midterm, should we know what the Isolobal Principle is/how to implement it? We didn't really go over it in class, so I was just wondering!
(Relating to problem 3.101)

Thanks!
Wed Nov 08, 2017 9:41 pm
Forum: Electronegativity
Topic: Electronegativity and Bond Strength
Replies: 4
Views: 618

Re: Electronegativity and Bond Strength

I had the same logic. But, in problem 3.87 of the textbook, it says "Note that electronegativity and polarity arguments would predict the C-F bond to be the weakest [out of CF4, CCl4, and CBr4]," and that confused me. I also did some research online, and most are coming to the conclusion t...
Wed Nov 08, 2017 9:38 pm
Forum: Dipole Moments
Topic: Direction of the Dipole moment arrow [ENDORSED]
Replies: 3
Views: 345

Re: Direction of the Dipole moment arrow[ENDORSED]

That's a really good question, I had the same question too. I have just been using the arrow that points towards the most negative charge (with the plus over the positive atom), as that's how my TA has been doing it in discussions.
Sun Nov 05, 2017 9:46 pm
Forum: Properties of Electrons
Topic: Energy Levels and Frequencies
Replies: 3
Views: 435

Energy Levels and Frequencies

I know that as an electron jumps from n = 1, n = 2, etc. there is an increase in energy. But if as n increases there is an increase in energy, why is n = 1 the UV region, n = 2 the visible light region, and n = 3 the infrared region? Doesn't the UV region have the highest frequency/energy, and if it...
Sat Nov 04, 2017 6:34 pm
Forum: Ionic & Covalent Bonds
Topic: covalent and ionic bonds
Replies: 3
Views: 281

Re: covalent and ionic bonds

Also, you can tell whether it will form an ionic or covalent bond by looking at the difference in electronegativities of the two atoms that are bonding. If the difference is greater than 2, it's going to be an ionic bond. But, if the difference between that same atom and another atom is less than 1....
Sat Nov 04, 2017 6:31 pm
Forum: Resonance Structures
Topic: Bonds
Replies: 4
Views: 342

Re: Bonds

Just adding on, I always check the formal charges of the atoms after I've made the Lewis structure. If you are able to get the formal charge of atoms to be zero by changing some of the bonds, then that's preferable!
Fri Nov 03, 2017 4:39 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Ionization energy vs. electron affinity [ENDORSED]
Replies: 5
Views: 574

Re: Ionization energy vs. electron affinity[ENDORSED]

Karen Ung 1C wrote:According to the book, the ionization energy is the minimum amount of energy needed to remove an electron from a gas-phase atom, and electron affinity is the energy released when an electron is added to a gas-phase atom.

by "gas-phase," does this just mean a noble gas? thank you!!
Fri Nov 03, 2017 4:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal planar vs. Trigonal bipyramidal
Replies: 4
Views: 651

Re: Trigonal planar vs. Trigonal bipyramidal

Hi, I am not sure if this is what you're asking, but the difference between the two is: • a trigonal planar shape has only one plane, and has only 3 bonding regions • on the other hand, the trigonal bipyramidal shape has a plane, in addition to two electron bonding regions both above and below the p...
Fri Nov 03, 2017 4:32 pm
Forum: Ionic & Covalent Bonds
Topic: Electronegativity and Covalent Bonds
Replies: 2
Views: 222

Re: Electronegativity and Covalent Bonds

Hi! I hope this is helpful, but this was my understanding: an atom that has a very high electronegativity means that it has a great ability to attract electrons (these are going to be the elements on the top right corner of the periodic table). When an atom with a very high electronegativity bonds w...
Fri Oct 20, 2017 6:43 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: orbitals an shells [ENDORSED]
Replies: 5
Views: 597

Re: orbitals an shells[ENDORSED]

Katie 1E wrote:In this definition are you using the terms "shells" and "subshells" interchangeably? Or is there a difference between the two?

I think that shells come before subshells, and orbitals come after subshells; so the order would be: shells (n), subshells (l), orbitals (ml).
Fri Oct 20, 2017 6:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrostatic (Coulomb) Potential Energy Equation
Replies: 1
Views: 204

Electrostatic (Coulomb) Potential Energy Equation

Hi, can someone explain the electrostatic coulomb potential energy equation, and how/when we use it?
Fri Oct 13, 2017 11:33 am
Forum: Properties of Light
Topic: Balmer Vs. Lyman
Replies: 12
Views: 1542

Re: Balmer Vs. Lyman

I am confused as to what n1 and n2 represent. What exactly does it symbolize? n1 and n2 as well as n3, n4...(so on) each represent the different energy levels that electrons occupy within an atom, where n1 would be the energy level closest to the nucleus (lowest energy level). Further, electrons wi...
Fri Oct 13, 2017 11:20 am
Forum: Properties of Light
Topic: 1.15
Replies: 4
Views: 305

Re: 1.15

The first thing I did was use v=c/λ to find the frequency of the wave. The value you get here can then be used to evaluate for n(final) in Rydberg's formula, since you know that n(initial) is 1 (because hydrogen starts at n=1). After plugging in all of your calculated values, all you have to do is ...
Wed Oct 04, 2017 11:13 pm
Forum: Balancing Chemical Reactions
Topic: Help on HW question H1
Replies: 5
Views: 334

Re: Help on HW question H1

Essentially, it is not allowed because you would be completely changing the reaction itself--adding an O to the product side would be adding a product that did not have a reactant to begin with, so the reaction would not resemble the original reaction at all.
Wed Oct 04, 2017 11:05 pm
Forum: Balancing Chemical Reactions
Topic: H7 // Book Problem Clarification
Replies: 4
Views: 373

Re: H7 // Book Problem Clarification

Yes, that is correct. If I'm right, catalysts are not consumed during reactions, but only serve to speed up the rate of the chemical reaction. In other words, they are not a reactant or a product, so you would not include them in the chemical equation! Hope that helps!