Search found 30 matches

by Tarek Abushamma
Mon Jun 11, 2018 4:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Atom vs lone pair
Replies: 3
Views: 102

Re: Atom vs lone pair

Lone pairs have higher electron - electron repulsion and thus they take up more space than atoms, pushing the surrounding atoms closer together and lowing their bonding angle.
by Tarek Abushamma
Mon Jun 11, 2018 4:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: HW 17.33
Replies: 6
Views: 289

Re: HW 17.33

I think it could be monodentate or bidentate as well, it would depend on which would produce the most stable structure.
by Tarek Abushamma
Mon Jun 11, 2018 3:45 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Lone Pairs Affecting Bond Angles/Shape?
Replies: 4
Views: 272

Re: Lone Pairs Affecting Bond Angles/Shape?

Lone pairs reduce bonding angles because they take up more space, resulting from their higher electron-electron repulsion, but I'm not exactly sure what you mean by something that has more than one pair having a specific name.
by Tarek Abushamma
Sun Jun 03, 2018 2:13 pm
Forum: Ionic & Covalent Bonds
Topic: Help on 3.25 [ENDORSED]
Replies: 3
Views: 173

Re: Help on 3.25 [ENDORSED]

Keep in mind that the roman numerals indicate of the charge of the element. Ex: bismuth(III) has a +3 charge.
by Tarek Abushamma
Sun Jun 03, 2018 2:07 pm
Forum: Dipole Moments
Topic: 6.1 and 6.19 question
Replies: 3
Views: 178

Re: 6.1 and 6.19 question

No it has to do with the shape. Since CH3(CH2)3CH3 is linear, it has a greater surface area, and thus more contact points for london forces to occur. The more interactions there are the stronger they are as a unit, which translates to the higher the boiling point.
by Tarek Abushamma
Sun Jun 03, 2018 2:00 pm
Forum: Lewis Structures
Topic: Test Q.8 [ENDORSED]
Replies: 7
Views: 276

Re: Test Q.8 [ENDORSED]

Think of the bonds in a resonance structure with single and double bonds as a blend between the two. In reality, the molecule will not have discrete single and double bonds, rather all its bonds will be the same intermediate mix between single and double bonds. You could sort of think of it like a &...
by Tarek Abushamma
Sun May 27, 2018 10:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: structure SF4
Replies: 2
Views: 82

Re: structure SF4

The lone pair takes up space, so you could not arrange the fluorine atoms in a tetrahedral shape.
by Tarek Abushamma
Sun May 27, 2018 10:25 pm
Forum: Resonance Structures
Topic: Contributing to Resonance Structures
Replies: 4
Views: 255

Re: Contributing to Resonance Structures

Whatever structure has the lowest energy state(such as the most favorable formal charge) contributes the most to resonance structure; so if all that separates equally low energy states is the position of a double bond, then showing all the alternate double bond positions would be the correct thing t...
by Tarek Abushamma
Sun May 27, 2018 10:19 pm
Forum: Dipole Moments
Topic: dipole moments and polarization
Replies: 3
Views: 113

Re: dipole moments and polarization

In water the dipole moments are not linearly opposing each other, which is why they do not cancel each other out. For this reason the molecule is polar.
by Tarek Abushamma
Sun May 20, 2018 9:44 pm
Forum: Octet Exceptions
Topic: Expanded Octet
Replies: 2
Views: 196

Re: Expanded Octet

Are there any cases where all 10 extra are taken up?
by Tarek Abushamma
Sun May 20, 2018 9:36 pm
Forum: Lewis Structures
Topic: Friday's Lecture [ENDORSED]
Replies: 4
Views: 181

Re: Friday's Lecture [ENDORSED]

Test three only covers chapter 3.
by Tarek Abushamma
Sun May 20, 2018 9:35 pm
Forum: Ionic & Covalent Bonds
Topic: 3.25 c)
Replies: 4
Views: 167

Re: 3.25 c)

The cation of Hydrogen is just a proton, so there probably are not any electron shells associated with it.
by Tarek Abushamma
Sun May 13, 2018 12:43 pm
Forum: Lewis Structures
Topic: formal charge?
Replies: 3
Views: 559

Re: formal charge?

Formal charge can be calculated using the formula: (# of valence electrons on an atom) - (non bonded electrons + number of bonds).
by Tarek Abushamma
Sun May 13, 2018 12:37 pm
Forum: Properties of Electrons
Topic: Electron Affinity
Replies: 4
Views: 282

Re: Electron Affinity

These trends have many of exceptions, however, so it is also important to take the element's electron configuration into consideration when determining how it would respond to additional electrons.
by Tarek Abushamma
Sun May 13, 2018 11:49 am
Forum: Ionic & Covalent Bonds
Topic: 3.33
Replies: 5
Views: 161

Re: 3.33

Also be mindful of exceptions, like oxygen, which has a lower ionization energy than nitrogen, yet is not in the center for the lewis dot of NO3.
by Tarek Abushamma
Sun May 06, 2018 11:23 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: test 2 #4
Replies: 4
Views: 181

Re: test 2 #4

I believe E=-hR/n^2 is only valid for hydrogen, yet this equation was not needed on the test.
by Tarek Abushamma
Sun May 06, 2018 11:14 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Everyday Objects and heisenberg's equation [ENDORSED]
Replies: 2
Views: 139

Re: Everyday Objects and heisenberg's equation [ENDORSED]

With large everyday objects we can measure momentum and position with great precision, so the resulting uncertainty is negligible.
by Tarek Abushamma
Sun May 06, 2018 11:08 am
Forum: Photoelectric Effect
Topic: 1.69
Replies: 2
Views: 154

Re: 1.69

In order to solve this problem first convert the 2.93 eV to J. Then, convert both given wavelengths into J using E=hv to see which one corresponds to an energy greater than the 2.93 eV. After you decide which laser has the higher E, subtract the work function from this value in order to find the ene...
by Tarek Abushamma
Sun Apr 29, 2018 11:31 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes [ENDORSED]
Replies: 6
Views: 200

Re: Nodal Planes [ENDORSED]

Nodal planes specify that there is 0 probability of finding an electron at that nodal plane, the don't really specify much about the way electrons are distributed in the areas that have a significant probability.
by Tarek Abushamma
Sun Apr 29, 2018 11:13 am
Forum: Photoelectric Effect
Topic: What is work function? [ENDORSED]
Replies: 15
Views: 1578

Re: What is work function? [ENDORSED]

The equation to solve for the work function is E(Photon)=Work Function(Threshold Energy) + E(Kinetic)
by Tarek Abushamma
Sun Apr 29, 2018 11:08 am
Forum: *Shrodinger Equation
Topic: Shrodinger Equation
Replies: 7
Views: 318

Re: Shrodinger Equation

I don't think we will have to directly apply the Shrodinger Equation to any problems in this course.
by Tarek Abushamma
Sun Apr 22, 2018 12:21 pm
Forum: DeBroglie Equation
Topic: HW 1.33
Replies: 12
Views: 450

Re: HW 1.33

8.8nm would still be a part of the X-ray spectrum, I believe.
by Tarek Abushamma
Sun Apr 22, 2018 12:16 pm
Forum: DeBroglie Equation
Topic: DeBrogile Module
Replies: 6
Views: 200

Re: DeBrogile Module

SI unit for distance is the meter and for time is the second, so you did the correct thing by converting it.
by Tarek Abushamma
Wed Apr 18, 2018 1:07 pm
Forum: DeBroglie Equation
Topic: HW 1.33
Replies: 12
Views: 450

Re: HW 1.33

You can use this given frequency to calculate the threshold energy using the equation, E = (h)(v). From there you should be able to use the work function to calculate the energy of the photon needed to displace an electron the given 3.6x10^3 km/s.
by Tarek Abushamma
Sat Apr 14, 2018 10:37 pm
Forum: Empirical & Molecular Formulas
Topic: Combustion Reaction [ENDORSED]
Replies: 6
Views: 249

Re: Combustion Reaction [ENDORSED]

I meant can you use a combustion reaction to find the empirical formula of a compound that does not contain oxygen? Or will oxygen always be present in the final empirical formula?
by Tarek Abushamma
Sat Apr 14, 2018 10:27 pm
Forum: Empirical & Molecular Formulas
Topic: Combustion Reaction [ENDORSED]
Replies: 6
Views: 249

Combustion Reaction [ENDORSED]

When using a combustion reaction to find the empirical formula of a compound, will oxygen always be one of the elements we are tying to solve for?
by Tarek Abushamma
Sat Apr 14, 2018 10:07 pm
Forum: Properties of Light
Topic: Quantized v. Discrete
Replies: 5
Views: 143

Re: Quantized v. Discrete

A discrete variable is something that has a defined set of possible values. A hydrogen atom is an example, as we can not have .33 or 1.7 hydrogen atoms. Instead, only discrete whole values (1 atom, 5 atoms, 456 atoms) are valid to quantify the variable.
by Tarek Abushamma
Sat Apr 14, 2018 8:21 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer Series
Replies: 2
Views: 48

Re: Balmer Series

Yes, I believe the Balmer series falls within the visible region of approximately 400nm - 700nm.
by Tarek Abushamma
Sat Apr 14, 2018 8:08 pm
Forum: Significant Figures
Topic: Sig fifs in 750 [ENDORSED]
Replies: 6
Views: 376

Re: Sig fifs in 750 [ENDORSED]

Yes, both of those would have two significant figures. Putting decimals less than one in scientific notation makes it very easy to tell which numbers are significant as only the digits that appear before the "x10" are.
by Tarek Abushamma
Sat Apr 14, 2018 7:41 pm
Forum: Photoelectric Effect
Topic: ENERGY PER MOLE OF PHOTONS [ENDORSED]
Replies: 3
Views: 125

Re: ENERGY PER MOLE OF PHOTONS [ENDORSED]

The units of Avogadro's number is "things" per mole, which is why when the energy of a photon is given per mole, we have to multiply by Avogadro's number to determine energy per photon.

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