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by nickianel_4b
Thu Dec 05, 2019 6:10 pm
Forum: Polyprotic Acids & Bases
Topic: Chelate/polydentate
Replies: 2
Views: 30

Re: Chelate/polydentate

I think once a polydentate ligand binds to a transition metal then it becomes a chelate.
by nickianel_4b
Thu Dec 05, 2019 6:03 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Base
Replies: 4
Views: 31

Re: Conjugate Base

^^I know that it becomes CH3COO- just from practice, but can someone remind me again why it donates the H+ at the end and not one of the H+ ions attached to the C?
by nickianel_4b
Thu Dec 05, 2019 5:58 pm
Forum: Conjugate Acids & Bases
Topic: Hydrogen Question
Replies: 2
Views: 29

Re: Hydrogen Question

Lavelle slightly discussed this in the lecture on Wednesday, when talking about polyprotic acids. Polyprotic acids can donate more than 1 H+, whereas monoprotic acids can only donate 1. So when trying to get a conjugate base, it just depends on the acid you're working with.
by nickianel_4b
Thu Dec 05, 2019 5:54 pm
Forum: Conjugate Acids & Bases
Topic: conjugate acids/bases
Replies: 4
Views: 34

Re: conjugate acids/bases

HA + B --> A- + BH
which is the same thing as
parent acid+parent base-->conjugate base+conjugate acid

As you can see the parent acid donates its H+ and becomes a conjugate base. The parent base accepts the H+ and becomes a conjugate acid.
by nickianel_4b
Thu Dec 05, 2019 5:41 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 6
Views: 36

Re: Conjugate Acids and Bases

My TA wrote this on the board in discussion:
HA + B --> A- + BH
parent acid + parent base --> conjugate base + conjugate acid

So yeah writing out the equation is helpful because then you can more easily see how the role of conjugate acid/base relates to the movement of the H+.
by nickianel_4b
Tue Nov 26, 2019 9:16 pm
Forum: Naming
Topic: HW 9c.9
Replies: 4
Views: 32

Re: HW 9c.9

The formula for ethylenediamine is C2H4(NH2)2. If you picture the Lewis structure in your head or draw it out, you can see there are 2 different lone pairs, so yes it's bidentate. This means that there are two covalent bonds for every ethylenediamine, making the coordination number 6.
by nickianel_4b
Tue Nov 26, 2019 9:05 pm
Forum: Naming
Topic: 9C3d
Replies: 4
Views: 59

Re: 9C3d

I don't think it matter whether you write H2O or OH2. But yes, as stated above, it's only written OH2 to emphasize the structure of the compound.
by nickianel_4b
Tue Nov 26, 2019 9:00 pm
Forum: Naming
Topic: Organometallic complex
Replies: 2
Views: 19

Re: Organometallic complex

I think Dr. Lavelle said in lecture that the term organometallic complex is used when at least one compound in the complex is organic. I don't think we have to know much about it though.
by nickianel_4b
Tue Nov 26, 2019 8:58 pm
Forum: Naming
Topic: Writing the formula given the compound
Replies: 4
Views: 566

Re: Writing the formula given the compound

When would you put an overall charge on the coordination compound? There's a list of ligands and I think we just have to memorize which ones are neutral and which have charges. Then we can determine the charge on the metal ion using the Roman numeral given, and using these we can determine the over...
by nickianel_4b
Tue Nov 26, 2019 8:53 pm
Forum: Naming
Topic: 9C.3
Replies: 6
Views: 48

Re: 9C.3

I thought it was because aqua comes first alphabetically before oxalato.
by nickianel_4b
Sat Nov 23, 2019 10:50 pm
Forum: Naming
Topic: Naming/Coord Comp
Replies: 4
Views: 185

Re: Naming/Coord Comp

^^ yep [Ni(CN)4]2- is tetracyanonickelate(II). As you can see the ligand is first with its prefix, then the transition metal with its Roman numeral, and it ends in -ate because of its negative charge.
by nickianel_4b
Sat Nov 23, 2019 10:47 pm
Forum: Naming
Topic: Negative charge with Coordination Compound
Replies: 3
Views: 23

Re: Negative charge with Coordination Compound

I think if a coordination compound is positively charged, the naming is the same as if there was no charge.
by nickianel_4b
Sat Nov 23, 2019 10:42 pm
Forum: Naming
Topic: Prefixes
Replies: 4
Views: 33

Re: Prefixes

if the ligand already has a name with di, tri, tetra, or penta
by nickianel_4b
Fri Nov 22, 2019 4:51 pm
Forum: Lewis Acids & Bases
Topic: Lewis & Bronsted
Replies: 3
Views: 24

Re: Lewis & Bronsted

Lewis and Bronsted acids/Lewis and Bronsted bases are the same thing, just different ways of viewing them.
by nickianel_4b
Fri Nov 22, 2019 4:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Definition of a Ligand
Replies: 4
Views: 23

Re: Definition of a Ligand

Yes, it's an ion or molecule attached to a metal atom, and together they form a coordination compound.
by nickianel_4b
Thu Nov 14, 2019 4:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: difference between trigonal planar and tetrahedral
Replies: 4
Views: 24

Re: difference between trigonal planar and tetrahedral

Trigonal planar-- central atom has 3 bonding pairs, angles are all 120
Tetrahedral-- central atom has 4 bonding pairs, angles are all 109.5
by nickianel_4b
Thu Nov 14, 2019 4:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance VSEPR
Replies: 6
Views: 34

Re: Resonance VSEPR

No--single, double, and triple bonds are all considered regions of e- density in the VSEPR model. Since they're all treated the same, it doesn't matter.
by nickianel_4b
Thu Nov 14, 2019 4:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: molecular shape vs. molecular geometry
Replies: 4
Views: 34

Re: molecular shape vs. molecular geometry

Molecular shape just considers the position of the atoms within the molecule.
by nickianel_4b
Thu Nov 14, 2019 4:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Arrangement and Shape
Replies: 2
Views: 29

Re: Arrangement and Shape

My TA gave us a worksheet in discussion that used molecular shape and electron geometry interchangeably, and it used molecular geometry and electron arrangement interchangeably. And these are the definitions he wrote on the board: molecular shape/electron geometry-- doesn't consider lone pairs, just...
by nickianel_4b
Thu Nov 14, 2019 4:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal pyramidal angles
Replies: 4
Views: 30

Re: Trigonal pyramidal angles

They don't have to add up to 360 because 360 is for a 2D circle, whereas molecular geometry deals with 3D shapes.
by nickianel_4b
Fri Nov 08, 2019 7:05 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Shape of Molecule
Replies: 5
Views: 26

Re: Shape of Molecule

Yes, for example, as Dr. Lavelle said in lecture: instantaneous dipoles in two rod-shaped molecules are closer, so therefore stronger than in two spherical molecules. This means that rod-shaped molecules would require more energy to break apart (like when boiling) than with spherical molecules.
by nickianel_4b
Fri Nov 08, 2019 7:00 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Interaction Potential Energy
Replies: 3
Views: 30

Re: Interaction Potential Energy

Forming bonds releases energy (negative value) while breaking bonds requires energy (positive value).
by nickianel_4b
Fri Nov 08, 2019 6:58 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: DNA
Replies: 3
Views: 20

Re: DNA

I think it just has to do with the hydrogen being attracted to the lone pairs of electrons on the nitrogen and oxygen atoms.
by nickianel_4b
Fri Nov 08, 2019 6:51 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dispersion forces
Replies: 6
Views: 40

Re: Dispersion forces

Alison Trinh 1A wrote:What exactly is a dispersion force?


A dispersion force is the same as a van der Waals force or induced dipole-induced dipole force. It's an intermolecular force that occurs when electron distribution causes two molecules to form temporary dipoles and become attracted.
by nickianel_4b
Fri Nov 08, 2019 6:45 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dispersion
Replies: 3
Views: 16

Re: Dispersion

Octadecane (C18H38) has more electrons than pentadecane (C15H32) which has more electrons than pentane (C5H12). The more electrons in a molecule, the more they can cause electron distortion in a nearby atom or molecule, making the induced dipole-induced-dipole forces stronger.
by nickianel_4b
Sat Nov 02, 2019 4:11 pm
Forum: Ionic & Covalent Bonds
Topic: Dissociation energy
Replies: 3
Views: 22

Re: Dissociation energy

Dissociation energy can be obtained from heat in a chemical reaction.
by nickianel_4b
Sat Nov 02, 2019 3:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structure
Replies: 5
Views: 68

Re: Lewis Structure

Also important to note is that when drawing the Lewis structure of ions, after you've finished, draw brackets around the whole thing and write the charge outside the brackets.
by nickianel_4b
Sat Nov 02, 2019 3:52 pm
Forum: Lewis Structures
Topic: Angstrom Measurements on Lewis Structures
Replies: 3
Views: 19

Re: Angstrom Measurements on Lewis Structures

I think they are important to know conceptually. There isn't a formula or anything to calculate them--we would just have to convert it from meters or another measurement of length.
by nickianel_4b
Sat Nov 02, 2019 3:49 pm
Forum: Lewis Structures
Topic: BF3
Replies: 3
Views: 32

Re: BF3

BF3 is unique because B often does not have an octet. The B atom simply forms three bonds with the 3 F atoms, so this is an exception to the octet rule.
by nickianel_4b
Sat Nov 02, 2019 3:44 pm
Forum: Lewis Structures
Topic: Radical
Replies: 2
Views: 21

Re: Radical

Radicals are defined as compounds with an unpaired e-, and the converse is true--that compounds with an even number of electrons are not radicals. Important to note that because of the one unpaired e-, radicals are highly reactive and exist for only a short time (because they are likely to react and...
by nickianel_4b
Fri Oct 25, 2019 7:25 pm
Forum: Lewis Structures
Topic: Anion
Replies: 7
Views: 59

Re: Anion

Similarly with cations, take the charge into account when counting the number of valence electrons, and then put brackets around the structure with the charge written on the outside.
by nickianel_4b
Fri Oct 25, 2019 7:19 pm
Forum: Lewis Structures
Topic: Expanded Valence Shells Example
Replies: 2
Views: 20

Re: Expanded Valence Shells Example

Yes, Dr. Lavelle used the sulfate ion example to show how to calculate formal charge and the phosphorus pentachloride example to show exceptions to the octet rule (expanded valence shells).
by nickianel_4b
Fri Oct 25, 2019 7:05 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 4
Views: 32

Re: Bond lengths

Yes, this is called a resonance hybrid, when the structure is an average of its resonance structures.
by nickianel_4b
Fri Oct 25, 2019 7:00 pm
Forum: Resonance Structures
Topic: defintion
Replies: 7
Views: 70

Re: defintion

It's also important to note that the real structure is usually a blend, or an average of all of its resonance structures. So for example, Dr. Lavelle used a nitrate ion, which has 3 resonance structures. But through experimental observation, each N-O bond has the same bond length, meaning that each ...
by nickianel_4b
Fri Oct 25, 2019 6:48 pm
Forum: Octet Exceptions
Topic: Atoms with expanded octets
Replies: 4
Views: 306

Re: Atoms with expanded octets

Yes, because the d-orbitals in the valence shell can accommodate additional electrons.
by nickianel_4b
Sat Oct 19, 2019 8:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions
Replies: 2
Views: 42

Re: Exceptions

The exceptions are when electrons move from the 4s orbital to a 3d orbital. I think this is just because it's more stable for the atom to have all half-full or full 3d orbitals than for them to be uneven. The examples Dr. Lavelle used in class are Cr: [Ar] 3d5 4s1 instead of [Ar] 3d4 4s2 Cu: [Ar] 3d...
by nickianel_4b
Sat Oct 19, 2019 8:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 7
Views: 55

Re: Writing Electron Configurations

I think we just write that when we need to show that, like in your nitrogen example, the three electrons in the 2p state are occupying different orbitals.
by nickianel_4b
Sat Oct 19, 2019 8:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Outer electrons
Replies: 2
Views: 33

Re: Outer electrons

During lecture, he also used the example of a fire with people surrounding it. If there's an inner circle of people and then a larger outer circle of people surrounding the fire, the people in the outer circle will experience less heat, kind of like how the valence electrons don't experience the ful...
by nickianel_4b
Sat Oct 19, 2019 8:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Why 3d before 4s
Replies: 2
Views: 31

Re: Why 3d before 4s

I think the 4s and 3d states are already really close to each other to begin with, and Dr. Lavelle said that for multi-electron atoms after atomic number 20, the 4s state is higher in energy than 3d.
by nickianel_4b
Sat Oct 19, 2019 7:59 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Applications of Hund’s Rule and Pauli Exclusion Principle
Replies: 2
Views: 21

Re: Applications of Hund’s Rule and Pauli Exclusion Principle

Pauli Exclusion Principle--no more than 2 electrons per orbital, and if they're in the same orbital they must have opposite spins Hund's Rule--due to electron repulsion, electrons in the same subshell occupy different orbitals and with parallel spin I'm not sure if they really help in writing electr...
by nickianel_4b
Fri Oct 11, 2019 5:14 pm
Forum: Properties of Electrons
Topic: Ionization energy
Replies: 4
Views: 48

Re: Ionization energy

In any one row in the periodic table, all of the elements' atoms have the same number of energy levels. However, going from left to right in one row, the atomic number increases, meaning the number of protons increases. The more protons, the greater the attraction to the electrons, and therefore, th...
by nickianel_4b
Fri Oct 11, 2019 5:10 pm
Forum: Properties of Electrons
Topic: Atomic Spectra and Energy Levels
Replies: 5
Views: 42

Re: Atomic Spectra and Energy Levels

There are specific frequencies shown in atomic spectra that are unique to each element. That is why each element is said to have a spectral fingerprint.
by nickianel_4b
Fri Oct 11, 2019 5:07 pm
Forum: Properties of Electrons
Topic: Circular Standing Wave
Replies: 3
Views: 43

Re: Circular Standing Wave

During the lecture, he showed us two different pictures of the circular standing wave. One said "allowed energy level" and the other said "not allowed." In the not allowed one, the wave was disconnected at one point and didn't continue around the circle--this is what happens when...
by nickianel_4b
Fri Oct 11, 2019 4:53 pm
Forum: DeBroglie Equation
Topic: Applying the DeBroglie Equation
Replies: 6
Views: 43

Re: Applying the DeBroglie Equation

The De Broglie equation says that any moving particle with momentum p has wavelike properties with wavelength λ, so it's applicable for any moving particle.
by nickianel_4b
Fri Oct 11, 2019 4:50 pm
Forum: DeBroglie Equation
Topic: exhibiting wave-like properties
Replies: 4
Views: 264

Re: exhibiting wave-like properties

During the lecture when we were discussing De Broglie's equation, he said that any moving particle that has a wavelength smaller than 10^-15 m does not have detectable wavelike properties. Instead it will behave more like a particle.
by nickianel_4b
Sun Oct 06, 2019 11:34 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 3
Views: 43

Re: Atomic Spectra

And each different wavelength that is emitted by these atoms corresponds to a different color.
by nickianel_4b
Sun Oct 06, 2019 11:27 pm
Forum: Properties of Light
Topic: Photons
Replies: 4
Views: 40

Re: Photons

I'd say that photons are a type of particle that represent the a unit of light that is emitted/absorbed.
by nickianel_4b
Sun Oct 06, 2019 6:34 pm
Forum: Properties of Light
Topic: c = fλ
Replies: 9
Views: 74

Re: c = fλ

Does anyone know if this equation is used for other types of waves? I'm trying to do 1A #7 for the homework, and it gives the frequency and I have to find the wavelength, but the wave is an x ray.
by nickianel_4b
Sat Oct 05, 2019 4:24 pm
Forum: Properties of Light
Topic: Quantum Mechanics
Replies: 9
Views: 77

Re: Quanta and Photons

ShastaB4C wrote:Is there a difference between quanta and photons?


Quanta are the smallest unit of a quantity, so photons are a type of quanta. One photon is one quantum of electromagnetic energy. Hope that helped!!
by nickianel_4b
Sat Oct 05, 2019 4:09 pm
Forum: Properties of Light
Topic: Classical Mechanics vs. Quantum Mechanics
Replies: 4
Views: 30

Re: Classical Mechanics vs. Quantum Mechanics

I agree with what everyone else said, basically quantum mechanics explains behavior at such a small level that everything is in discrete amounts (like photons and atoms, or the water molecules from his water bucket example). I think that's why he also said you can't have 1.2 or 2.33 of something in ...

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