Search found 38 matches

by Shash Khemka 1K
Fri Dec 07, 2018 10:28 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Charge versus size
Replies: 1
Views: 211

Re: Charge versus size

You have to factor in size as well as charge. Be2+ would have a higher polarizing power since it is similar in size to Li+ but it has a higher charge. The higher charge indicates a stronger pull towards the nucleus due to the reduced amount of electrons. Hope this helps, good luck studying!
by Shash Khemka 1K
Fri Dec 07, 2018 10:22 am
Forum: Naming
Topic: Final Exam
Replies: 2
Views: 79

Re: Final Exam

I'm not sure if you're referencing VSEPR Names or Coordination Compound names but, either or, we have to memorize both. I doubt a sheet will be provided. Hope this helped, good luck studying!
by Shash Khemka 1K
Fri Dec 07, 2018 10:20 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong Acids
Replies: 5
Views: 136

Re: Strong Acids

We should know the concept and theory differentiating strong and weak acids. As for the calculations, I feel as if it would primarily be strong acids but there is always the possibility he could throw a weak acid in there. Can't say for sure. Hope this helped, good luck studying!
by Shash Khemka 1K
Wed Dec 05, 2018 1:13 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Ordering Polarizability and Polarizing Power
Replies: 4
Views: 378

Re: Ordering Polarizability and Polarizing Power

Anions: P3- < S2- < Cl- < I- ; Smallest to Largest


Cations: Ba2+ < Cs+ < Ca2+ < Li+ ; Largest to Smallest
by Shash Khemka 1K
Thu Nov 29, 2018 9:45 pm
Forum: Hybridization
Topic: CH2O hybridization
Replies: 9
Views: 2584

Re: CH2O hybridization

AX3's hybridization would be SP2.

Hybridization is simply

Linear: sp
Trigonal Planar: sp2
Tetrahedral: sp3
Trigonal Bipyramidal: sp3d
Octahedral: sp3d2
by Shash Khemka 1K
Thu Nov 29, 2018 9:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 7
Views: 162

Re: Dipole moment

The larger the electronegativity difference, the larger the dipole moment.
by Shash Khemka 1K
Thu Nov 29, 2018 9:41 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: Intermolecular Forces (Melting Pts.)
Replies: 2
Views: 268

Re: Intermolecular Forces (Melting Pts.)

A simple way to consider melting points is larger atom → more electrons → higher polarizability (easily distortable electron cloud) → stronger intermolecular bond → higher boiling/melting point. CHI3 is a larger atom compared to CHF3. Regarding the electronegativity question, I don't think it matter...
by Shash Khemka 1K
Thu Nov 29, 2018 9:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polar and non polar molecules from a lewis structure
Replies: 8
Views: 183

Re: Determining polar and non polar molecules from a lewis structure

You can usually tell if a molecule is polar or nonpolar based on its Lewis Structure. A good rule of thumb is that a nonpolar molecule will always be symmetrical and its dipole movements will cancel out (neutral charge). Polar molecules are not symmetrical and their dipole movements will result in a...
by Shash Khemka 1K
Thu Nov 29, 2018 9:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar or not polar
Replies: 4
Views: 132

Re: polar or not polar

You can usually tell if a molecule is polar or nonpolar based on its Lewis Structure. A good rule of thumb is that a nonpolar molecule will always be symmetrical and its dipole movements will cancel out (neutral charge). Polar molecules are not symmetrical and their dipole movements will result in a...
by Shash Khemka 1K
Thu Nov 29, 2018 9:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: repulsion
Replies: 3
Views: 100

Re: repulsion

Lone pairs dictate the shape of a central atom because they are providing a charge that alters the shape of the structure through repulsions. A way I think about it is that the lone pair is pushing on that central atom, moving it up/down/side-to-side, causing the entire structure to alter its shape....
by Shash Khemka 1K
Thu Nov 29, 2018 9:15 pm
Forum: Sigma & Pi Bonds
Topic: Sigma bonds
Replies: 6
Views: 191

Re: Sigma bonds

Sigma bonds can either have an S-S orbital bond, S-P orbital bond, or P-P orbital bond. They connect and overlap end-to-end. The S-S orbital bond looks like a Venn Diagram, the S-P orbital bond looks like a circle overlapping one portion of a dumbbell, and the P-P orbital bond looks like two dumbbel...
by Shash Khemka 1K
Thu Nov 29, 2018 2:20 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 6
Views: 308

Re: Sigma and Pi Bonds

Yeah, that's correct. A single bond will have 1 sigma bond, 0 pi bonds. A double bond will have 1 sigma bond, 1 pi bond. A triple bond will have 1 sigma bond, 2 pi bonds. Using this reasoning, we can say that a molecule with 2 double bonds and 1 triple bond will have 3 sigma bonds and 4 pi bonds.
by Shash Khemka 1K
Sat Nov 24, 2018 1:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: double and triple bonds
Replies: 10
Views: 186

Re: double and triple bonds

Single, Double, and Triple bonds are all one region of electron density. Bond type does not affect the naming of the VSEPR structure, each bond is counted as one region of electron density.
by Shash Khemka 1K
Sat Nov 24, 2018 1:46 pm
Forum: Hybridization
Topic: Writing out Hybridization
Replies: 8
Views: 125

Re: Writing out Hybridization

I'm pretty sure Dr. Lavelle said it was up to our preference regarding which placement we use.
by Shash Khemka 1K
Sat Nov 24, 2018 1:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 3
Views: 96

Re: polarity

The only way, to my knowledge, that a symmetrical structure could be polar is if the atoms on opposing sides are different elements. Other than that, symmetrical structures with the same elements on either side are usually non-polar.
by Shash Khemka 1K
Sat Nov 24, 2018 1:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Slightly less than bond angles
Replies: 4
Views: 69

Re: Slightly less than bond angles

We can just answer slightly less than. I don't think we are expected to know the exact angle because it can differ from structure to structure at a minute level.
by Shash Khemka 1K
Wed Nov 14, 2018 3:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Q4B
Replies: 4
Views: 170

Re: Midterm Q4B

De Broglie's hypothesis relates to the wave-like behavior that matter portrays. The reason electron diffraction supports De Broglie's hypothesis is due to the fact that the electrons are portraying properties of waves by diffracting through a crystal. Light portrays wave-like properties for the same...
by Shash Khemka 1K
Wed Nov 14, 2018 3:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron density
Replies: 6
Views: 129

Re: Electron density

Yes, it refers only to the central atom. Electron density is counted as 1 for single, double, and triple bonds. You can utilize Electron Density in naming structures in regards to the "count" by referencing and memorizing the "counts" for names.
by Shash Khemka 1K
Wed Nov 14, 2018 3:26 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 13
Views: 459

Re: Formal Charge

An ion will never have an overall formal charge of 0. It is ideal to put the disbalance on the outer atoms to have a more stable Lewis Structure. Hope this helped out!
by Shash Khemka 1K
Tue Nov 06, 2018 5:22 pm
Forum: Lewis Structures
Topic: Lewis Structure for NO2
Replies: 3
Views: 66

Re: Lewis Structure for NO2

Nitrogen has a lower electronegativity than Oxygen so it goes in the middle.
by Shash Khemka 1K
Tue Nov 06, 2018 5:21 pm
Forum: Electronegativity
Topic: Electron affinity
Replies: 5
Views: 132

Re: Electron affinity

Electron affinity increases through a period due to the fact that, as we go through a period, there is an increasing amount of valence electrons. The affinity would be the highest at the rightmost side of the periodic table because group 7 elements only need 1 more electron to complete their octet. ...
by Shash Khemka 1K
Tue Nov 06, 2018 5:12 pm
Forum: Resonance Structures
Topic: Finding all Resonance Structures
Replies: 4
Views: 119

Re: Finding all Resonance Structures

I don't think there are any "tricks" for resonance structures. It's pretty much just trial and error while making sure formal charges fit the structure. The only "trick" I can think of is when there are double bonds to similar elements that can be exchanged with each other such a...
by Shash Khemka 1K
Fri Nov 02, 2018 6:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Scantron
Replies: 6
Views: 148

Re: Scantron

I don't think we need anything because Prof. Lavelle would have told us by now; plus, I don't think the test would be multiple choice so there would be no need for a scantron. I'm pretty sure our midterm has to be done in pen because that's how we have been doing our tests so far. Hope this helps!
by Shash Khemka 1K
Fri Nov 02, 2018 6:39 pm
Forum: Octet Exceptions
Topic: s vs d orbital
Replies: 2
Views: 50

Re: s vs d orbital

It is preferable for orbitals to be fully filled. We can do this by taking 2 electrons from s2 and give it to d8. This allows the d orbital to be fully filled and "happy".
by Shash Khemka 1K
Fri Nov 02, 2018 6:35 pm
Forum: Formal Charge and Oxidation Numbers
Topic: shortcut for FC
Replies: 6
Views: 163

Re: shortcut for FC

I'm pretty sure the shortcut is [Valence Electrons of the element] - [# of Electrons and Bonds drawn onto that specific element] = FC.
by Shash Khemka 1K
Thu Oct 25, 2018 5:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: orbital positions
Replies: 2
Views: 97

Re: orbital positions

They should be. The labels for the D-Orbitals are:
xy
yz
zx
x2y2
z2
by Shash Khemka 1K
Thu Oct 25, 2018 5:50 pm
Forum: Photoelectric Effect
Topic: unit conversion hw Q 1.3
Replies: 2
Views: 139

Re: unit conversion hw Q 1.3

You should generally always convert wavelength into meters when substituting into an equation. Just remember to put your answer back into the form that the question is asking for. Hope this helps!
by Shash Khemka 1K
Thu Oct 25, 2018 5:35 pm
Forum: Properties of Electrons
Topic: mass of electron
Replies: 5
Views: 213

Re: mass of electron

They give it to us on the test. I checked my last test and it gave us the electron's mass so I'm assuming it'll be given on this test as well. However, it wouldn't hurt to memorize it. Hope this helps!
by Shash Khemka 1K
Thu Oct 18, 2018 12:43 pm
Forum: Properties of Light
Topic: Corresponding Wavelength/Frequency for Each Type of Wave?
Replies: 2
Views: 80

Re: Corresponding Wavelength/Frequency for Each Type of Wave?

Hey, Nicholas, there actually is a range of measurements to correlate wavelength/frequency to identify what type of wave it is. I attached an image to this post that shows the ranges. Hope this helps!
by Shash Khemka 1K
Thu Oct 18, 2018 12:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What exactly are nodes?
Replies: 1
Views: 46

Re: What exactly are nodes?

A node is a point where the electron probability is 0. It's basically a region in a space where the wavefunction passes through. Hope this helps!
by Shash Khemka 1K
Thu Oct 18, 2018 12:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Class Grading
Replies: 9
Views: 357

Re: Class Grading

I think the class isn't curved because, on the syllabus, there is a 500 point total grade already calculated out. Plus, I remember hearing people say that the class might not be curved. I'm not 100% sure but I hope this helps!
by Shash Khemka 1K
Thu Oct 11, 2018 1:10 pm
Forum: *Particle in a Box
Topic: Purpose of Particle in a Box
Replies: 2
Views: 354

Re: Purpose of Particle in a Box

The Particle in a Box problem, when solved, can give possible values of Energy and Wavefunction as well as the probability of pinpointing a particle's position inside the "box" at a specific energy level. To be honest, I am not 100% certain on how exactly to solve these kinds of problems m...
by Shash Khemka 1K
Thu Oct 11, 2018 12:52 pm
Forum: Balancing Chemical Reactions
Topic: Chemical compounds
Replies: 3
Views: 197

Re: Chemical compounds

I think we might need to know how to write basic chemical compounds -> names but I am not sure. I doubt they're expecting us to know complex compound formulas from names just yet. If your TA told you something regarding the test then you should probably take that into account because I feel like the...
by Shash Khemka 1K
Thu Oct 11, 2018 12:40 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 10
Views: 112

Re: Wavelength

You should convert all the units to be the same before you start the problem so you're working with the same measurements. However, I do not think it matters what units your answer is in unless the question specifically asks for it. As long as the value is the same, it should not matter if your answ...
by Shash Khemka 1K
Wed Oct 03, 2018 4:52 pm
Forum: SI Units, Unit Conversions
Topic: state of compounds
Replies: 3
Views: 89

Re: state of compounds

I think it would be a good idea to put the states of the compounds because I remember Dr. Lavelle and my TA talking about how they wanted us to put the states of the compounds for HW and Tests. The question will usually give you the state of the compound by either wording it or giving you the subscr...
by Shash Khemka 1K
Wed Oct 03, 2018 4:45 pm
Forum: Significant Figures
Topic: Do sig figs only refer to decimals?
Replies: 3
Views: 65

Re: Do sig figs only refer to decimals?

Hey, Brianna, sig figs do not only refer to decimals, but they can also actually refer to any integer at all. Keep these 3 rules in mind: 1) All nonzero numbers are significant Ex) 1,2,3,4,5, ... 2) When a zero is surrounded by nonzero numbers, it is considered significant. This can also apply to mo...
by Shash Khemka 1K
Wed Oct 03, 2018 4:32 pm
Forum: Significant Figures
Topic: sig fig for avogadros number
Replies: 3
Views: 97

Re: sig fig for avogadros number

Avogadro's number has a constant value of 6.022 x 10^23. Because Avogadro's number is constant, its significant numbers in any given problem would not change. You can use either 6.02 x 10^23 or 6.022 x 10^23 but, since the solutions manual uses 6.022 x 10^23, I think it would be better to use that v...

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