Search found 22 matches

by Andrea ORiordan 1L
Wed Dec 06, 2017 10:28 pm
Forum: Lewis Acids & Bases
Topic: 12.53
Replies: 2
Views: 45

Re: 12.53

The main concept for that question is that having more electronegative atoms on an acid makes it stronger-- when a proton is released, the resulting anion is more stable as a result of the electronegative atoms stabilizing the negative charge left by the release of the proton.
by Andrea ORiordan 1L
Wed Dec 06, 2017 10:24 pm
Forum: Naming
Topic: Suffixes
Replies: 4
Views: 67

Re: Suffixes

You use bis, tris, tetrakis, etc, if the ligand already contains a greek prefix (eg. ethyleneDIamine) or if it is polydentate (eg. oxalate).
by Andrea ORiordan 1L
Tue Nov 28, 2017 4:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Converting between constants
Replies: 2
Views: 26

Re: Converting between constants

I don't believe so. Dr. Lavelle briefly went over it but said we wouldn't have to do it on this exam, at least.
by Andrea ORiordan 1L
Tue Nov 28, 2017 4:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and liquids
Replies: 1
Views: 37

Re: Solids and liquids

Liquids and solids are omitted from the equilibrium constant expression because, as you said, they do not change in concentration. Solids and liquids are virtually incompressible compared to gases. Pressure changes won't really affect the volume of a liquid or solid sample, whereas pressure changes ...
by Andrea ORiordan 1L
Tue Nov 28, 2017 4:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: Abbreviating e- configurations [ENDORSED]
Replies: 7
Views: 100

Re: Abbreviating e- configurations [ENDORSED]

No, we won't get marked down to my knowledge. Usually he uses px, py, and pz when explaining specific concepts that require those notations to be understood, such as hybridization.
by Andrea ORiordan 1L
Mon Nov 20, 2017 6:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: KP versus KC
Replies: 3
Views: 36

Re: KP versus KC

The only way Kp is different than Kc is in the units. You can also convert Kp to Kc fairly easily, and therefore it makes sense that they represent effectively the same thing. Kp is used for simplicity in equations only utilizing gases.
by Andrea ORiordan 1L
Mon Nov 20, 2017 5:58 pm
Forum: Naming
Topic: Example 17.1
Replies: 2
Views: 41

Re: Example 17.1

They specify the oxidation number with given roman numerals that so many transition metals have multiple oxidation states.
by Andrea ORiordan 1L
Mon Nov 13, 2017 12:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR for four electron densities
Replies: 2
Views: 30

Re: VSEPR for four electron densities

Yes, the hybridization would be the same. Look at NH3 and NH4+ as examples, and you see that they both have sp3 hybridization. Hybridization does not depend on the number of lone pairs versus the number of bonded atoms- it only depends on regions of electron density, which can be either.
by Andrea ORiordan 1L
Mon Nov 13, 2017 12:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Extent of memorization [ENDORSED]
Replies: 2
Views: 26

Re: Extent of memorization [ENDORSED]

We'll also have to know that the repulsion between a lone pair of an electrons and a bond is greater than the repulsion between two bonds- so knowing that something with a tetrahedral electron geometry will have bond angles of slightly less than 109.5 between the bonds is important too. But we won't...
by Andrea ORiordan 1L
Tue Nov 07, 2017 11:39 am
Forum: Resonance Structures
Topic: Resonance structure and formal charges
Replies: 2
Views: 40

Re: Resonance structure and formal charges

You kind of just have to experiment a little bit. There's also an easier way to figure out formal charge- you just count the number of electrons the bonded atom controls (count a bond as one electron and a lone pair as two) and compare it to the number of valence electrons it normally has. If it con...
by Andrea ORiordan 1L
Tue Nov 07, 2017 11:33 am
Forum: Octet Exceptions
Topic: Radicals And Biradicals
Replies: 2
Views: 51

Re: Radicals And Biradicals

Radicals and Biradicals are extremely reactive and generally don't last very long in nature- for example, methyl on its own is so unstable that it cannot be stored.
by Andrea ORiordan 1L
Mon Oct 30, 2017 11:43 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Determining Formal Charge [ENDORSED]
Replies: 3
Views: 55

Re: Determining Formal Charge [ENDORSED]

There's also an easier way to determine formal charge than to use the formula. You just see how many valence electrons that atom normally has, and compare it to how many electrons it has in the structure (a bond counts as one electron, a lone pair counts as two). If it has more electrons than it nor...
by Andrea ORiordan 1L
Mon Oct 30, 2017 11:40 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Super Octet [ENDORSED]
Replies: 2
Views: 69

Re: Super Octet [ENDORSED]

This happens in periods 3 or higher, especially with p-block elements. This is because they have available d-orbitals that aren't filled with electrons that can be used in bonding. It results in a formal charge closer to 0, which makes the structure lower energy and more stable.
by Andrea ORiordan 1L
Mon Oct 23, 2017 1:12 pm
Forum: Quantum Numbers and The H-Atom
Topic: Abbreviating e- configurations [ENDORSED]
Replies: 7
Views: 100

Re: Abbreviating e- configurations [ENDORSED]

Another notation style includes listing each sub-orbital (i.e. px, py, pz) with the number of electrons in that orbital (i.e. 2px1). That's also just a convention, and it's fine to just write p instead of separating it into 3 sub-orbitals.
by Andrea ORiordan 1L
Mon Oct 23, 2017 1:01 pm
Forum: Trends in The Periodic Table
Topic: Effective Nuclear Charge and Electron shielding [ENDORSED]
Replies: 2
Views: 72

Re: Effective Nuclear Charge and Electron shielding [ENDORSED]

Electron shielding refers to the repulsion between two negative electrons, which decreases the nuclear charge/pull towards the nucleus that any one shielded electron "feels". The effective nuclear charge is the pull towards the nucleus that an electron "feels".
by Andrea ORiordan 1L
Wed Oct 18, 2017 6:27 pm
Forum: DeBroglie Equation
Topic: Quantum Dog [ENDORSED]
Replies: 2
Views: 95

Quantum Dog [ENDORSED]

Hello! Just a hypothetical question- if a large object (a dog, per say) slowed down to a very, very, very, very slow speed (think 10^-30 m/s), would it have observable wavelike properties? I'm aware that classical objects are made up of billions of particles and therefore you can't really calculate ...
by Andrea ORiordan 1L
Wed Oct 18, 2017 6:22 pm
Forum: Properties of Electrons
Topic: Hydrogen series
Replies: 5
Views: 99

Re: Hydrogen series

If we are expected to do calculations with other series besides the Balmer and Lyman series, the principle quantum number of the series (n) will probably just be given. I wonder how many series have actually been experimentally observed?
by Andrea ORiordan 1L
Thu Oct 12, 2017 3:20 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 5271
Views: 508704

Re: Post All Chemistry Jokes Here

Why do white bears dissolve in water? Because they're polar.
by Andrea ORiordan 1L
Thu Oct 12, 2017 3:15 pm
Forum: DeBroglie Equation
Topic: Should velocity always be in m.s. when solving? [ENDORSED]
Replies: 11
Views: 228

Re: Should velocity always be in m.s. when solving? [ENDORSED]

To have your units correctly cancel, stick with the metric system's SI units while solving the equation. If the answer asks for velocity- say, in mph- you should complete the problem using the metric system & SI units, and then convert your answer to the desired units using dimensional analysis.
by Andrea ORiordan 1L
Thu Oct 12, 2017 3:12 pm
Forum: *Black Body Radiation
Topic: Ultraviolet Catastrophe
Replies: 3
Views: 416

Re: Ultraviolet Catastrophe

Classical physics assumes than an oscillator (i.e. a charged particle) could oscillate at any energy, and therefore emit electromagnetic radiation at very high frequencies. Planck's hypothesis says that radiation of higher frequencies can only be generated when an oscillator of that higher frequency...
by Andrea ORiordan 1L
Tue Oct 03, 2017 5:59 pm
Forum: Molarity, Solutions, Dilutions
Topic: E.15 homework question [ENDORSED]
Replies: 4
Views: 93

Re: E.15 homework question [ENDORSED]

Dr. Lavelle also said that he would go over the naming of compounds- and we'll probably go over oxidation numbers too. So don't worry if you don't automatically know the formula of calcium sulfide.
by Andrea ORiordan 1L
Tue Oct 03, 2017 3:54 pm
Forum: Empirical & Molecular Formulas
Topic: F.1 textbook exercise
Replies: 3
Views: 115

Re: F.1 textbook exercise

For this upcoming test, we do not need to know how to write chemical formulas from their names (i.e. Nitric Acid is HNO3)- both the name of the compound and the formula (or just the formula) will be given to us. Dr. Lavelle said we would go over this in class at some point.

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