Search found 25 matches
- Sun Dec 10, 2017 10:25 am
- Forum: Octet Exceptions
- Topic: Exceptions [ENDORSED]
- Replies: 7
- Views: 1312
Re: Exceptions [ENDORSED]
ALSO! remember to look at formal charges!
- Sun Dec 10, 2017 10:17 am
- Forum: Hybridization
- Topic: Composition of a Bond
- Replies: 6
- Views: 876
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)
- Sun Dec 10, 2017 10:14 am
- Forum: Amphoteric Compounds
- Topic: Amphoteric [ENDORSED]
- Replies: 4
- Views: 960
Re: Amphoteric [ENDORSED]
Do amphoteric compounds encompass amphiprotic compounds as well?
- Tue Dec 05, 2017 11:29 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: HF
- Replies: 4
- Views: 710
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.
- Tue Dec 05, 2017 11:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 11.9
- Replies: 2
- Views: 543
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.
I think it just wanted you to balance the equation so that the coefficients are at the lowest whole number ratio.
- 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: 1675
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.
- Sun Dec 03, 2017 9:39 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE Box
- Replies: 3
- Views: 635
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!
If Q < 1, then you subtract from the reactants as products are forming. If Q > 1, then you add to the reactants!
- Sun Nov 26, 2017 6:51 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate ligands
- Replies: 2
- Views: 429
Re: Polydentate ligands
How do you determine the denticity of a ligand? For example, how would you know whether OH2 is a polydentate?
- Sun Nov 26, 2017 6:49 pm
- Forum: Hybridization
- Topic: Pi Bonds vs. Sigma Bonds
- Replies: 7
- Views: 1079
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.
- Sun Nov 19, 2017 11:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Radicals
- Replies: 4
- Views: 602
Re: Radicals
Do radical electrons count as a region of electron density?
- Sun Nov 19, 2017 11:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar ve non polar [ENDORSED]
- Replies: 7
- Views: 1000
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.
- Sun Nov 19, 2017 11:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR
- Replies: 3
- Views: 466
Re: VSEPR
I think the only concerns regarding VSEPR models are the areas of electron denisty (lone pairs and bonds).
- Mon Nov 06, 2017 5:26 pm
- Forum: Electronegativity
- Topic: ELECTRON AFFINITY
- Replies: 7
- Views: 1596
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 ...
- Mon Nov 06, 2017 5:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Magnetic Quantum Number
- Replies: 6
- Views: 1055
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...
- Mon Nov 06, 2017 5:03 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic and Covalent Bonds
- Replies: 9
- Views: 1153
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 ...
- Mon Nov 06, 2017 4:51 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Paramagnetic- Q3F 2013 Final
- Replies: 3
- Views: 793
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...
- Mon Nov 06, 2017 4:47 pm
- Forum: Octet Exceptions
- Topic: Incomplete Octet Vs Radical [ENDORSED]
- Replies: 2
- Views: 762
Re: Incomplete Octet Vs Radical [ENDORSED]
Similarly, radical molecules will have an odd # of electrons. Make sure to count the charge, too!
- Mon Nov 06, 2017 4:46 pm
- Forum: Octet Exceptions
- Topic: When to expand an octet
- Replies: 2
- Views: 834
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...
- Sun Oct 22, 2017 4:11 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: quantum numbers [ENDORSED]
- Replies: 5
- Views: 1111
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...
- Sun Oct 22, 2017 3:57 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 4s 3d or 3d 4s?
- Replies: 3
- Views: 1798
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...
- Sun Oct 15, 2017 5:03 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Post Assessment Module 30C
- Replies: 4
- Views: 709
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...
- Sun Oct 15, 2017 4:59 pm
- Forum: Photoelectric Effect
- Topic: photoelectric effect post-module assessment [ENDORSED]
- Replies: 5
- Views: 674
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...
- Sun Oct 15, 2017 4:58 pm
- Forum: Photoelectric Effect
- Topic: photoelectric effect post-module assessment [ENDORSED]
- Replies: 5
- Views: 674
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...
- Tue Oct 03, 2017 10:36 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 34519
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 ...
- Tue Oct 03, 2017 10:25 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 34519
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...