Search found 25 matches

by JonathanLam1G
Sun Dec 10, 2017 10:25 am
Forum: Octet Exceptions
Topic: Exceptions [ENDORSED]
Replies: 7
Views: 328

Re: Exceptions [ENDORSED]

ALSO! remember to look at formal charges!
by JonathanLam1G
Sun Dec 10, 2017 10:17 am
Forum: Hybridization
Topic: Composition of a Bond
Replies: 6
Views: 342

Re: Composition of a Bond

Does anyone know why the pi bond is often (O 2p, O 2p) for let's say a double bond between two O atoms....and not (O 2sp^2, O 2sp^2)
by JonathanLam1G
Sun Dec 10, 2017 10:14 am
Forum: Amphoteric Compounds
Topic: Amphoteric [ENDORSED]
Replies: 4
Views: 409

Re: Amphoteric [ENDORSED]

Do amphoteric compounds encompass amphiprotic compounds as well?
by JonathanLam1G
Tue Dec 05, 2017 11:29 pm
Forum: Identifying Acidic & Basic Salts
Topic: HF
Replies: 4
Views: 223

Re: HF

Cl, Br, and I all combine to form strong acids because F is more electronegative (stronger attachment to H), but also because Cl, Br and I have more electron shielding, so they are more easily removed.
by JonathanLam1G
Tue Dec 05, 2017 11:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.9
Replies: 2
Views: 143

Re: 11.9

CH4(g) + 3 Cl2(g) <=> CHCl3(g) + 3 HCl(g)

I think it just wanted you to balance the equation so that the coefficients are at the lowest whole number ratio.
by JonathanLam1G
Sun Dec 03, 2017 10:33 pm
Forum: Bronsted Acids & Bases
Topic: How do I identify if a molecule is a Bronsted Acid or Base?
Replies: 5
Views: 207

Re: How do I identify if a molecule is a Bronsted Acid or Base?

Keliana Hui 3H wrote:whats the difference between a Lewis acid/base and a Bronsted acid/ base?


Lewis acids/bases involve donating/accepting an electron, while Bronsted acids/bases involve donating/accepting H+ ions a.k.a. protons.
by JonathanLam1G
Sun Dec 03, 2017 9:39 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Box
Replies: 3
Views: 287

Re: ICE Box

You have to calculate Q first.
If Q < 1, then you subtract from the reactants as products are forming. If Q > 1, then you add to the reactants!
by JonathanLam1G
Sun Nov 26, 2017 6:51 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate ligands
Replies: 2
Views: 156

Re: Polydentate ligands

How do you determine the denticity of a ligand? For example, how would you know whether OH2 is a polydentate?
by JonathanLam1G
Sun Nov 26, 2017 6:49 pm
Forum: Hybridization
Topic: Pi Bonds vs. Sigma Bonds
Replies: 7
Views: 261

Re: Pi Bonds vs. Sigma Bonds

Sigma bonds are free to rotate and change orientation, while pi bonds are locked in place since they have two points of interference.
by JonathanLam1G
Sun Nov 19, 2017 11:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Radicals
Replies: 4
Views: 192

Re: Radicals

Do radical electrons count as a region of electron density?
by JonathanLam1G
Sun Nov 19, 2017 11:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar ve non polar [ENDORSED]
Replies: 7
Views: 307

Re: Polar ve non polar [ENDORSED]

Can someone explain to me why SiO2 is polar? I drew the lews dot structure and came up with a structure very similar to carbon dioxide, which is nonpolar.
by JonathanLam1G
Sun Nov 19, 2017 11:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 3
Views: 145

Re: VSEPR

I think the only concerns regarding VSEPR models are the areas of electron denisty (lone pairs and bonds).
by JonathanLam1G
Mon Nov 06, 2017 5:26 pm
Forum: Electronegativity
Topic: ELECTRON AFFINITY
Replies: 7
Views: 492

Re: ELECTRON AFFINITY

Are there any exceptions to the electron affinity increasing across the period? The first couple elements in group 5 (N, P, As) have lower electron affinities than the group 4 counterparts in their row (C, Si, Ge), because the group 4 elements want an extra electron to complete their half p shells ...
by JonathanLam1G
Mon Nov 06, 2017 5:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Magnetic Quantum Number
Replies: 6
Views: 277

Re: Magnetic Quantum Number

Is there any way for us to tell exactly what magnetic quantum number an electron would have within an orbital without doing an experiment? Will we ever be asked which magnetic quantum number an electron has? By convention, the first half of any orbital (d1 - d5) has +1/2 spins while the latter half...
by JonathanLam1G
Mon Nov 06, 2017 5:03 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 9
Views: 321

Re: Ionic and Covalent Bonds

I've always held the notion that ionic bonds were stronger than covalent bonds (it takes more [heat] energy to melt salt than it does to melt ice), but the Sunday review session (3 - 4 pm) the TA mentioned that ionic bonds are weaker in water. My question is as follows: given a question "Order ...
by JonathanLam1G
Mon Nov 06, 2017 4:51 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Paramagnetic- Q3F 2013 Final
Replies: 3
Views: 371

Re: Paramagnetic- Q3F 2013 Final

Does the first electron to enter an orbital always have an upwards magnetic spin? Due to convention, we designate the first half of elements in each orbital with the +1/2 spin and the latter half with negative spin, but I believe, as per mentioned on a recent test question, that both positive and n...
by JonathanLam1G
Mon Nov 06, 2017 4:47 pm
Forum: Octet Exceptions
Topic: Incomplete Octet Vs Radical [ENDORSED]
Replies: 2
Views: 166

Re: Incomplete Octet Vs Radical [ENDORSED]

Similarly, radical molecules will have an odd # of electrons. Make sure to count the charge, too!
by JonathanLam1G
Mon Nov 06, 2017 4:46 pm
Forum: Octet Exceptions
Topic: When to expand an octet
Replies: 2
Views: 169

Re: When to expand an octet

I agree. I believe the order of priority when drawing Lewis Structures should be: 1) Can the atom have an expanded octet? or can it only hold 8 valence electrons? 2) Are the formal charges of the atoms the lowest possible? 3) If there must be a negative charge, is it placed on the most electronegati...
by JonathanLam1G
Sun Oct 22, 2017 3:11 pm
Forum: Quantum Numbers and The H-Atom
Topic: quantum numbers [ENDORSED]
Replies: 5
Views: 248

Re: quantum numbers [ENDORSED]

What happens to the quantum number as you move across the row? quantum number l changes as you move across certain groups of atoms in a row. The first two columns in a row will be in the s-orbital, so their l = 0. As we move toward the d-orbital (here you will find the metals), l = 2. The p-orbital...
by JonathanLam1G
Sun Oct 22, 2017 2:57 pm
Forum: Quantum Numbers and The H-Atom
Topic: 4s 3d or 3d 4s?
Replies: 3
Views: 233

Re: 4s 3d or 3d 4s?

When filling up orbitals with electrons, we fill 4s before 3d. However, we write the electron configuration of Scandium, for example, as [Ar] 3d3 4s2 because here, the 4s is now higher energy than the 3d. Does this mean that the energy levels of orbitals change relative to each other when they beco...
by JonathanLam1G
Sun Oct 15, 2017 4:03 pm
Forum: Photoelectric Effect
Topic: Photoelectric Post Assessment Module 30C
Replies: 4
Views: 245

Re: Photoelectric Post Assessment Module 30C

For Part C, you need to combine several equations to find the frequency. By combining KE= E-threshold, E=hv, and KE=1/2mv^2, you get frequency= (1/2mv^2 + threshold)/ h (Planck's constant) Remember to use the mass of an electron: 9.11 x 10^-31 kg for the mass and to square velocity when plugging in...
by JonathanLam1G
Sun Oct 15, 2017 3:59 pm
Forum: Photoelectric Effect
Topic: photoelectric effect post-module assessment [ENDORSED]
Replies: 5
Views: 283

Re: photoelectric effect post-module assessment [ENDORSED]

I have a question pertaining to #30. What is the frequency of the incident light on the sodium metal surface? I added the work function with the kinetic energy and got the energy of the incident light, but when I divided it by Planck's constant, I got 2.27 * 10^38 (answer B). This answer is incorrec...
by JonathanLam1G
Sun Oct 15, 2017 3:58 pm
Forum: Photoelectric Effect
Topic: photoelectric effect post-module assessment [ENDORSED]
Replies: 5
Views: 283

Re: photoelectric effect post-module assessment [ENDORSED]

I have a question pertaining to #30. What is the frequency of the incident light on the sodium metal surface? I added the work function with the kinetic energy and got the energy of the incident light, but when I divided it by Planck's constant, I got 2.27 * 10^38 (answer B). This answer is incorrec...
by JonathanLam1G
Tue Oct 03, 2017 9:36 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 90
Views: 7720

Re: All students read this sig fig post [ENDORSED]

When trying to figure out the sig. fig. of the final answer, do we take into account the sig. fig. of constants? I vaguely remember that my teacher for AP Chemistry said that we do not need to consider the sig. fig of constants (like Avogadro's number or speed of light) when we are determining the ...
by JonathanLam1G
Tue Oct 03, 2017 9:25 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 90
Views: 7720

Re: All students read this sig fig post [ENDORSED]

when finding the molar mass in the periodic table, how many sig figs do we use? I usually use one more than the lowest sig fig in the question. i.e. How many moles of oxygen are there in 10.8 g of water? I would use the molar masses oxygen and hydrogen to the hundreths decimal place, but I think if...

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