Search found 29 matches

by Kaleb Tesfaye 1I
Thu Jun 07, 2018 9:41 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Relative acidity
Replies: 2
Views: 199

Relative acidity

When Dr. Lavelle was explaining the characteristics of a strong acid, he mentioned how "oxoacids more readily lose H+ if resulting anion is stabilized by electron withdrawing atoms delocalize and stabilize the negative charge"? What does he mean by this?
by Kaleb Tesfaye 1I
Thu Jun 07, 2018 9:35 am
Forum: Bronsted Acids & Bases
Topic: Bronsted vs Lewis acids
Replies: 3
Views: 317

Bronsted vs Lewis acids

Is there any correlation between the definition of bronsted acids and Lewis acids. I can't seem to relate the two definitions.
by Kaleb Tesfaye 1I
Thu Jun 07, 2018 9:30 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Question on an example we did in class [ENDORSED]
Replies: 1
Views: 86

Re: Question on an example we did in class [ENDORSED]

The example he used was [Fe (CN)6]4-
There are 6 CN molecules with a charge of -1 each so the total charge of these molecules is -6. However, the net charge of the molecule is -4 which means Fe must have an oxidation state of 2+
by Kaleb Tesfaye 1I
Sat Jun 02, 2018 8:53 am
Forum: Naming
Topic: Chelate
Replies: 3
Views: 232

Chelate

I am having difficulty understanding what a Chelate is? What determines if a molecule will form a ring of atoms or not?
by Kaleb Tesfaye 1I
Sat Jun 02, 2018 8:50 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cisplatin [ENDORSED]
Replies: 1
Views: 128

Cisplatin [ENDORSED]

On Friday, Dr. Lavelle gave us an example of a complex molecule called cisplatin ( cis-diamine-dichloro-platinum (II))which forms a coordination compound with DNA to stops cell division. He mentioned how the to Cl molecules bond with the G section of DNA. I was wondering why the Cl molecule was the ...
by Kaleb Tesfaye 1I
Thu May 31, 2018 11:30 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Helpful Chart
Replies: 18
Views: 515

Re: Helpful Chart

Hey Rebekah. Based on what I have seen so far, it seems like you have to memorize them.
by Kaleb Tesfaye 1I
Thu May 31, 2018 11:26 am
Forum: Hybridization
Topic: List of the different shapes
Replies: 6
Views: 228

Re: List of the different shapes

I would also include T-shaped and Angular (bent)
by Kaleb Tesfaye 1I
Thu May 31, 2018 9:12 am
Forum: Hybridization
Topic: Hybridization and it's relation to valence electrons
Replies: 3
Views: 99

Hybridization and it's relation to valence electrons

If a carbon atom is bonded to another atom/s with only single bonds, will it always have a hypridization of 2sp3? Since regions of e- density is equal to the number of hybrid orbital, as long as carbon is not bonded with a double or triple bond, it will always have 4 hybrid orbitals right?
by Kaleb Tesfaye 1I
Thu May 31, 2018 9:05 am
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.19 part b and d
Replies: 3
Views: 138

Re: HW 4.19 part b and d

Hey Gianna
Can you clarify in what you meant when you said "0 LP"?
Also, how we do know which bonds to focus on when we do the VSEPR model. The CH3 molecule is tetrahedaral but the (CH3)2Be molecule is linear. Do we mention the shape and angle for both molecules?
by Kaleb Tesfaye 1I
Sat May 26, 2018 8:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar Vs. Nonpolar
Replies: 1
Views: 279

Polar Vs. Nonpolar

In class, we looked at some examples of molecules that were polar and nonpolar. One of the examples for a non polar molecule was Tetrachloromethane (CCl4). Then Dr. Lavelle demonstrated how a similar molecule, Trichloromethane (CHCl3) is a polar molecule because the dipole moments do not cancel. The...
by Kaleb Tesfaye 1I
Sat May 26, 2018 7:56 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 1
Views: 91

Polarity

Dr Lavelle mentioned how polar molecules interact with electrostatic potential energy that is created by a cation or anion. What did he mean by this?
by Kaleb Tesfaye 1I
Tue May 22, 2018 9:32 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 170

Bond Angles

Does the type of chemical bond (single, double or triple) affect the bond angle of a molecule?
by Kaleb Tesfaye 1I
Sun May 20, 2018 5:33 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Polarizability and boiling point
Replies: 2
Views: 674

Polarizability and boiling point

How does polarizability relate to the boiling point of a molecule? does a molecule have a low boiling point if it has a high Polarizability?
by Kaleb Tesfaye 1I
Sun May 20, 2018 5:28 am
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: 2
Views: 199

Interaction Potential energy

Dr. Lavelle mentioned how the attractive forces between two ions increases as ionic charge increases and as ionic size increases. Doesn't this contradict the interaction potential energy equation? (a1*q2/r^6) Were a is the polarizing potential r is the distance between the two since the equations is...
by Kaleb Tesfaye 1I
Sun May 20, 2018 5:17 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Fluctuating electron distribution [ENDORSED]
Replies: 1
Views: 187

Fluctuating electron distribution [ENDORSED]

Dr. Lavelle mentioned that when two molecules get close to each other, they start affecting each other's electron cloud. Does this hold true to Noble Gases as well? And if so, how does it compare to other elements?
by Kaleb Tesfaye 1I
Sun May 20, 2018 5:13 am
Forum: Dipole Moments
Topic: Polarization
Replies: 2
Views: 143

Polarization

When we are trying to determine the polarization of a molecule, are we always dealing with cations/anions?
by Kaleb Tesfaye 1I
Sun May 20, 2018 5:08 am
Forum: Dipole Moments
Topic: Dipole moment as a vector [ENDORSED]
Replies: 2
Views: 105

Dipole moment as a vector [ENDORSED]

It is my understanding that electrons tend to shift towards the more positive element/ molecule. For example, for HF, the electron cloud of the F- atom will be polarized and end up shifting toward the H+ atom. Why is the dipole moment represented by an arrow pointing toward the more negative atom if...
by Kaleb Tesfaye 1I
Wed May 16, 2018 9:02 am
Forum: Ionic & Covalent Bonds
Topic: Lewis Acids and Bases
Replies: 4
Views: 169

Lewis Acids and Bases

Is there any correlation between a molecule's bond and whether or not that determines if will be an acid or a base. For example, HCl is a strong acid that is a covalent bond. Does the fact that it is a covalent bond play any role in determining it's characteristic as a strong acid?
by Kaleb Tesfaye 1I
Wed May 16, 2018 8:50 am
Forum: Ionic & Covalent Bonds
Topic: Electron affinity [ENDORSED]
Replies: 6
Views: 209

Electron affinity [ENDORSED]

Even though electron affinity and ionization energy are opposites of each other (the former is energy required to add an e-, while the latter is energy required to remove an e-), they have the same trend on the periodic table. why is this this the case?
by Kaleb Tesfaye 1I
Wed May 16, 2018 8:42 am
Forum: Ionic & Covalent Bonds
Topic: Percentage Ionic Character
Replies: 4
Views: 180

Percentage Ionic Character

What is the minimum percentage requirement for a bond to be labeled as ionic? Does it just have to have more than 50 percent ionic character?
by Kaleb Tesfaye 1I
Thu May 10, 2018 11:26 am
Forum: Octet Exceptions
Topic: Octet exceptions and Formal charges.
Replies: 6
Views: 362

Octet exceptions and Formal charges.

Since elements in the third row or below can have octet exceptions, is it mandatory to use the formal charge to determine what kind of lewis structure they have and whether or not they have resonances?
by Kaleb Tesfaye 1I
Thu May 10, 2018 11:22 am
Forum: Resonance Structures
Topic: Resonance Structures and Formal charges
Replies: 7
Views: 288

Resonance Structures and Formal charges

What is the relationship between resonance structures and Formal charges? How does one relate to the other?
by Kaleb Tesfaye 1I
Thu May 10, 2018 11:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Relationship between Electromagnetic Radiation and Enrgy of the photon
Replies: 2
Views: 149

Re: Relationship between Electromagnetic Radiation and Enrgy of the photon

Electromagnetic radiation is usually tied with the wavelength and frequency of a particle. The ER of a photon is proportional to it's energy (Energy of a photon = h*frequency). The higher the frequency, the greater the energy and therefore, the greater its Electromagnetic radiation.
by Kaleb Tesfaye 1I
Thu May 10, 2018 11:11 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius and Ionic Radius
Replies: 2
Views: 158

Re: Atomic Radius and Ionic Radius

They are not the same thing but they do share the same pattern. For both cases, the radius of an element increases as you move down the periodic table and also as you move from the right to the left. However, the reasoning behind it is a bit different. For the atomic radius, it increases as you move...
by Kaleb Tesfaye 1I
Mon May 07, 2018 8:40 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Coulomb Potential Energy [ENDORSED]
Replies: 1
Views: 154

Re: Coulomb Potential Energy [ENDORSED]

Coulomb Potential Energy describes the electrostatic force between two charged particles (either protons or electrons) and is represented by the equation ((k)*(Q1*Q2))/R where Q1 is the charge of one particle, Q2 is the charge of another particle, R is the distance between the two particles, and K i...
by Kaleb Tesfaye 1I
Thu May 03, 2018 6:28 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence Shell Configuration (2.55)
Replies: 2
Views: 121

Re: Valence Shell Configuration (2.55)

Valence shell configuration is basically just the outermost shell of an atom. These are the electrons that are usually involved in bonding and reactions. The number of valence shell electrons is usually determined by the position of the atom in the periodic table. Atoms in Group 1 have 1 valence ele...
by Kaleb Tesfaye 1I
Tue May 01, 2018 12:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Atom Size (Periodicity of Atomic properties)
Replies: 2
Views: 97

Atom Size (Periodicity of Atomic properties)

According to Dr. Lavelle, the atomic size decreases as you move to the right on the periodic table because the nucleus charge is getting larger and therefor pulling electrons closer and closer. But since all electrons have the same charge, shouldn't they be repelling each other and therefore counter...
by Kaleb Tesfaye 1I
Tue May 01, 2018 12:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Shielding (H.W 2.37 part b)
Replies: 2
Views: 153

Electron Shielding (H.W 2.37 part b)

Can someone please explain to me what electron shielding is? To be specific, i don't understand why the following statement is true from homework problem 2.37 part b: "Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge ...
by Kaleb Tesfaye 1I
Thu Apr 19, 2018 5:05 am
Forum: DeBroglie Equation
Topic: HW 1.37 [ENDORSED]
Replies: 6
Views: 298

HW 1.37 [ENDORSED]

Protons and neutrons have nearly the same mass. How different are their wavelength? Calculate the wavelength of each particle when traveling at 2.75*10^5 m s^-1 in a particle accelerator and report the difference as a percentage of the wavelength of the neutron. In order to calculate their wavelengt...

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