Search found 33 matches

by Kelly Hollman
Sat Dec 08, 2018 1:31 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Least to most polarizing power?
Replies: 1
Views: 203

Least to most polarizing power?

On test #3 Q6B, how do we order the cations Li+, Ca2+, Cs+, Ba2+ in order from least to most polarizing power? I'm especially having trouble with putting Cs+ and Ba2+ in the right order.
by Kelly Hollman
Sat Dec 08, 2018 1:28 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Test 3
Replies: 1
Views: 200

Re: Test 3

It is the least polarizable because it is the smallest anion in that problem. Chlorine (even without the charge) is the smallest (remember that atomic radius decreases as you go across the periodic table!).
by Kelly Hollman
Wed Dec 05, 2018 2:19 pm
Forum: Bronsted Acids & Bases
Topic: Disassociation and stabilization?
Replies: 2
Views: 76

Re: Disassociation and stabilization?

Oxoacids, in particular, more readily lose H+ IF the resulting anion (the anion that results when H+ is released) is stabilized by electron withdrawing atoms. These electron withdrawing atoms, a.k.a atoms with greater electronegativities, delocalize and stabilize the negative charge of the anion. J...
by Kelly Hollman
Wed Dec 05, 2018 10:53 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 7
Views: 117

Re: Ligands

(As mentioned in the coordination compounds review session yesterday) The molecular geometry will not allow all three oxygens to be binding sites. If you think about the trigonal planar structure and angles, it is impossible to have more than two oxygens close enough to each other AND have them bond...
by Kelly Hollman
Wed Dec 05, 2018 10:51 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate and Coordination Number?
Replies: 2
Views: 92

Re: Polydentate and Coordination Number?

A coordination number is associated with the entire complex -- for example, if the TM has a monodentate ligand as well as a bidentate ligand, the coordination number will be 3.

Polydentates refer to the number of bonding areas (e.g., if there are lone pairs available for bonding) in a ligand.
by Kelly Hollman
Wed Dec 05, 2018 10:42 am
Forum: Lewis Acids & Bases
Topic: Resonance Structures
Replies: 4
Views: 86

Re: Resonance Structures

I don't believe that resonance structures should matter when determining if it is an acid or a base.
by Kelly Hollman
Wed Dec 05, 2018 10:37 am
Forum: Bronsted Acids & Bases
Topic: Disassociation and stabilization?
Replies: 2
Views: 76

Disassociation and stabilization?

How are disassociation and stabilization of acids related? I'm just a little confused as I read somewhere that higher electronegativity allows for acids to disassociate more easily, and thus causes them to be stronger acids. However, I also read that higher electronegativity allows for higher stabil...
by Kelly Hollman
Wed Dec 05, 2018 10:35 am
Forum: Bronsted Acids & Bases
Topic: Ka Formula
Replies: 6
Views: 125

Re: Ka Formula

Just keep in mind that Ka = Kforward rxn/Kreverse rxn When you have a higher Ka, then you have more products (e.g., more H+ ions). This increases the pH (more acidic). Vice versa, when you have a lower Ka, you have more reactants -- there aren't as many H+ ions being produced. This lowers the pH (le...
by Kelly Hollman
Wed Dec 05, 2018 10:23 am
Forum: Conjugate Acids & Bases
Topic: Inductive Effect
Replies: 5
Views: 122

Re: Inductive Effect

As electronegativity increases, inductive properties increase. This was mentioned in my discussion but I also don't recall the term itself being mentioned too often (if at all) in lecture. In lecture, we did learn that as electronegativity increases, stabilization is stronger, and those acids will b...
by Kelly Hollman
Wed Dec 05, 2018 10:19 am
Forum: Naming
Topic: Transition Metal
Replies: 4
Views: 64

Re: Transition Metal

From the review session about coordination compounds I attended yesterday, I believe it was mentioned that such cases are unlikely, so don't worry about them for the final.
by Kelly Hollman
Wed Dec 05, 2018 10:15 am
Forum: Lewis Acids & Bases
Topic: Lewis Acids and Bronstead Acids
Replies: 1
Views: 57

Re: Lewis Acids and Bronstead Acids

Check out Ch 12.1 and 12.2 in the book (6th edition; otherwise, there are likewise chapters in the 7th ed.) To summarize (taken directly from the book): Lewis Acids and Bases A Lewis acid is an electron pair acceptor . A Lewis base is an electron pair donor Bronsted-Lowry Acids and Bases An acid is ...
by Kelly Hollman
Wed Dec 05, 2018 10:05 am
Forum: Naming
Topic: Anionic ligands
Replies: 5
Views: 117

Re: Anionic ligands

Definitely look at the naming conventions chart on Dr. Lavelle's website: https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf
by Kelly Hollman
Wed Dec 05, 2018 10:04 am
Forum: Naming
Topic: Cyanide
Replies: 6
Views: 103

Re: Cyanide

They are the same -- just different naming conventions (one is newer, I think). It's on the naming coordination compounds chart from Dr. Lavelle's website.
https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf
by Kelly Hollman
Sat Nov 17, 2018 5:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar Angles
Replies: 3
Views: 65

Re: Square Planar Angles

All the angles are 90 degrees even with the two lone pairs! Keep in mind than when there is only one pair but five other atoms bonded to the central atom, the angles do become less than 90 degrees. (square pyramidal)
by Kelly Hollman
Sat Nov 17, 2018 5:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: tetrahedral vs trigonal planar
Replies: 9
Views: 154

Re: tetrahedral vs trigonal planar

Danny Elias Dis 1E wrote:How many lone pairs are possible when the molecule is in the trigonal planar shape?


There can be 3 regions for this shape, but I think we've only seen molecules in this shape with one lone pair, e.g. SO2, a bent shape.
by Kelly Hollman
Sat Nov 17, 2018 5:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: hybridization for VSEPR
Replies: 1
Views: 35

Re: hybridization for VSEPR

I think we should be able to figure out the hybridization of the central atom based on the electron geometry but also, there's a chart in our text book (table 4.2) that has been really helpful for me and might help you out too!
by Kelly Hollman
Fri Nov 16, 2018 6:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distance from Central Atom
Replies: 8
Views: 100

Re: Distance from Central Atom

The direct wedge is coming out of the page and the hatched wedge is going into the page!
by Kelly Hollman
Fri Nov 02, 2018 2:41 pm
Forum: Octet Exceptions
Topic: Boron Trifluoride class example
Replies: 3
Views: 84

Re: Boron Trifluoride class example

Fluorine needs on electron to fulfill an octet, so taking an electron away from it would be difficult and unlikely. A double bond between B and F would require that positive charge for Fluorine, so in this case, it won't happen.
by Kelly Hollman
Fri Nov 02, 2018 2:33 pm
Forum: Lewis Structures
Topic: Formal Charge Tricks
Replies: 5
Views: 193

Re: Formal Charge Tricks

You can think about it as formal charge = "should" - "has".
What your atom should have are the number of valence electrons according to the periodic table.
What your atom, when bonded, actually has are: (lone pair electrons) + (1/2)*(the number of bounded electrons).
by Kelly Hollman
Fri Nov 02, 2018 2:29 pm
Forum: Octet Exceptions
Topic: The center atom
Replies: 20
Views: 602

Re: The center atom

To start finding the structures of this acid, you should first, according to the book, "choose as the central atom the element with the lowest ionization energy." Here, oxygen has the lowest ionization energy (besides Hydrogen, which shouldn't be considered as the central atom). Oxygen as ...
by Kelly Hollman
Sun Oct 28, 2018 9:35 pm
Forum: Ionic & Covalent Bonds
Topic: Question regarding ionic bonds
Replies: 9
Views: 129

Re: Question regarding ionic bonds

Yup, and remember how iconic bonds are different from covalent bonds (which are between non-metals)
by Kelly Hollman
Sun Oct 28, 2018 9:33 pm
Forum: Ionic & Covalent Bonds
Topic: Exceptions
Replies: 4
Views: 123

Re: Exceptions

They don't have "space" to fill an octet. They only have room for 2 electrons in the outershell as they have S orbitals only!
by Kelly Hollman
Sun Oct 28, 2018 9:32 pm
Forum: Ionic & Covalent Bonds
Topic: bound atoms
Replies: 8
Views: 140

Re: bound atoms

They release energy when they are bound!
by Kelly Hollman
Fri Oct 19, 2018 9:46 pm
Forum: Photoelectric Effect
Topic: Equation units
Replies: 4
Views: 80

Re: Equation units

I agree, kg is the SI unit for mass.
by Kelly Hollman
Fri Oct 19, 2018 9:44 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Series and Wavelengths
Replies: 4
Views: 82

Re: Series and Wavelengths

I believe they are related through the Rydberg equation V = r (1/(n1^2) - (1/(n2^2)). When you calculate frequency, you may plug it into C = wavelength x frequency and solve for the wavelength. These wavelengths would then correspond to the wavelengths you see on figure 1.10. But keep in mind of the...
by Kelly Hollman
Thu Oct 18, 2018 5:54 pm
Forum: Einstein Equation
Topic: Number of photons
Replies: 7
Views: 408

Re: Number of photons

You can use dimensional analysis! The total energy multiplied by 1 photon / energy (obtained from E = hv)
by Kelly Hollman
Thu Oct 11, 2018 6:37 pm
Forum: DeBroglie Equation
Topic: Homework Question 1.33 (6th Ed)
Replies: 2
Views: 70

Re: Homework Question 1.33 (6th Ed)

I agree, you need to use the Debroglie equation because they give you velocity.
by Kelly Hollman
Wed Oct 10, 2018 2:41 pm
Forum: DeBroglie Equation
Topic: de Broglie Relationship
Replies: 3
Views: 116

Re: de Broglie Relationship

I agree, it's asking for the mass of the electron.
by Kelly Hollman
Wed Oct 10, 2018 2:38 pm
Forum: Properties of Light
Topic: Problem 1.9 6th Edition
Replies: 2
Views: 31

Re: Problem 1.9 6th Edition

I believe you can try converting MHz to Hz!

1 MHz = 1000000 Hz
by Kelly Hollman
Tue Oct 02, 2018 1:22 pm
Forum: Balancing Chemical Reactions
Topic: Audio Visual Focus Topics Balancing Chemical Equations Pre Assessment
Replies: 2
Views: 80

Re: Audio Visual Focus Topics Balancing Chemical Equations Pre Assessment

I believe the net amount will be moles of product (gas) - moles of reactant (gas)
by Kelly Hollman
Tue Oct 02, 2018 1:20 pm
Forum: Significant Figures
Topic: Mass Percent Composition
Replies: 4
Views: 107

Re: Mass Percent Composition

Use the smallest amount of sig figs you find in the given numbers. For example, if you are given 20.0 grams and 156.6 grams, you'd use three sig figs in your answer (20.0 has three, 156.6 has four.)
by Kelly Hollman
Tue Oct 02, 2018 1:17 pm
Forum: Empirical & Molecular Formulas
Topic: Audio Visual Focus Topic Empirical and Molecular Formulas Pre-Assessment
Replies: 2
Views: 91

Re: Audio Visual Focus Topic Empirical and Molecular Formulas Pre-Assessment

Yes, exactly. Each percentage is for each individual element of the vitamin.

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