Search found 56 matches
- Sat Dec 12, 2020 7:29 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Understanding Differences in Oxidation Number
- Replies: 2
- Views: 304
Re: Understanding Differences in Oxidation Number
That definitely makes more sense, thank you!
- Sat Dec 12, 2020 5:32 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Understanding Differences in Oxidation Number
- Replies: 2
- Views: 304
Understanding Differences in Oxidation Number
In one of the Sapling Homework Questions, ClO 4 - is given as a molecule with resonance structures. One part of the question asked for the Oxidation number of the Chlorine and I was a little confused as to why it doesn't seem to follow the trend of Oxidation numbers. From the periodic table, we can ...
- Sat Dec 12, 2020 5:18 pm
- Forum: Hybridization
- Topic: Differences in Sigma and Pi Bonds in Double Bonds
- Replies: 4
- Views: 404
Re: Differences in Sigma and Pi Bonds in Double Bonds
Sean Wang 1J wrote:Sigma bonds consist of hybrid orbitals, pi bonds consist of unhybridized orbitals. If there was another pi bond it would also be (C 2p, O 2p).
Okay cool, thank you so much!
- Sat Dec 12, 2020 5:16 pm
- Forum: Bond Lengths & Energies
- Topic: Higher Melting Point
- Replies: 28
- Views: 2688
Re: Higher Melting Point
I had a little confusion here as well. I would have thought that due to Fluorine having a higher electronegativity than Iodine that surely it would have a higher melting point. However, it seems that melting and boiling point depends on the bonds and intermolecular forces within the atom. Given Iodi...
- Sat Dec 12, 2020 5:05 pm
- Forum: Hybridization
- Topic: Differences in Sigma and Pi Bonds in Double Bonds
- Replies: 4
- Views: 404
Differences in Sigma and Pi Bonds in Double Bonds
In H 2 CO, there exists a double bond between the Carbon and the Oxygen. I understand that the hybridization of both C and O is sp 2 due to their 3 areas of electron density, but I had a little confusion about how the hybridization of the double bond works. The sigma bond is (C 2sp 2 , O 2sp 2 ) whi...
- Sat Dec 12, 2020 4:53 pm
- Forum: Lewis Structures
- Topic: HClO3 Lewis Structure [ENDORSED]
- Replies: 4
- Views: 1413
Re: HClO3 Lewis Structure [ENDORSED]
This was definitely a question I had as well following one of the review sessions. It seems that due to Oxygen's higher electronegativity than Chlorine, the Hydrogen is more likely to attach to the Oxygen. In conjunction with the answers above, this arrangement also helps to keep the formal charges ...
- Sat Dec 12, 2020 4:43 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Differences in Rotation between σ-Bonds and π-Bonds
- Replies: 5
- Views: 2196
Re: Differences in Rotation between σ-Bonds and π-Bonds
Pi-bonds have 2 areas of contact (the 2 p orbitals line up side to side!). Think of a ladder. If you try to move 1 ring but not the other, the ladder (bond) will break. For sigma bonds, they have 1 point of contact (end to end), think about wringing out a towel (lol), you can twist either way witho...
- Sun Dec 06, 2020 10:24 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Differences in Rotation between σ-Bonds and π-Bonds
- Replies: 5
- Views: 2196
Differences in Rotation between σ-Bonds and π-Bonds
I was wondering if someone could help clarify why pi-bonds restrict rotation while sigma-bonds allow for it. From what I can tell, the orientation of the electron density in relation to the intermolecular axis seems to play a role. Is it that the p-orbitals seen in pi-bonds are perpendicular to the ...
- Sun Dec 06, 2020 9:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Delocalized Bonds
- Replies: 5
- Views: 363
Re: Delocalized Bonds
There was an example given with Benzene (C 6 H 6 ) where the structure was seen to have a Delocalized ring of 6 electrons, each given by the 1 unhybridized electron of each Carbon. I was wondering, in this case, does the delocalization of the electrons mean that they are not specifically "attac...
- Sun Dec 06, 2020 9:43 pm
- Forum: Naming
- Topic: Naming in alphabetical order?
- Replies: 10
- Views: 594
Re: Naming in alphabetical order?
Does the rule of naming in alphabetical order also apply to Anions? I know it was mentioned that in order it would go "Anion name" "(Greek prefix)" then "hydrate" but how would this work in an example with multiple anions as well as with the alphabetical order of the Li...
- Sun Dec 06, 2020 8:49 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding vs Dipole-Dipole
- Replies: 2
- Views: 637
Re: Hydrogen Bonding vs Dipole-Dipole
Hydrogen bonds are stronger because of the atoms that are involved. Hydrogen bonding involves a H atom bound to a highly electronegative atom like N, O, and F. Since the hydrogen is bound to such an electronegative atom, the electronegative atom is pulling the electron density away from the hydroge...
- Sun Dec 06, 2020 12:20 pm
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding vs Dipole-Dipole
- Replies: 2
- Views: 637
Hydrogen Bonding vs Dipole-Dipole
After a review session where we discussed the relative strengths of 3 separate forces--London Dispersion Forces, Dipole-Dipole, and Hydrogen Bonding--I had a little trouble understanding why Hydrogen Bonds have higher energy than Dipole-Dipole interactions. From what I understand, both kinds of inte...
- Sun Nov 29, 2020 5:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial vs Equatorial Bonds
- Replies: 11
- Views: 3260
Re: Axial vs Equatorial Bonds
I makes more sense when you think of axial and equatorial bonds in terms of the 3-D arrangement of the molecule. The image I drew and attached might help you visualize its lay out. But yes, lone pairs are often in axial positions in order to minimize repulsions as you can see from many bent, pyrami...
- Sun Nov 29, 2020 4:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Tetrahedral vs Trigonal Pyramidal Structure
- Replies: 4
- Views: 817
Tetrahedral vs Trigonal Pyramidal Structure
I apologize if this seems like a straightforward question, but is the only distinction between a tetrahedral and trigonal pyramidal structure that trigonal pyramidal has one lone pair in one of its axial positions? I saw some examples of both that seem to give contradictory answers. Also, by this lo...
- Sun Nov 29, 2020 4:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial vs Equatorial Bonds
- Replies: 11
- Views: 3260
Re: Axial vs Equatorial Bonds
Equatorial atoms can exist on all 360 degrees of the central atom so long as they are in the same plane, and axial atoms can only occupy the space above and below or to the direct left and right of the central atom depending on how you are looking at the molecule. The relationship between these two...
- Sun Nov 29, 2020 4:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial vs Equatorial Bonds
- Replies: 11
- Views: 3260
Re: Axial vs Equatorial Bonds
I was having a bit of an issue understanding the differences between axial and equatorial bonds as well as how they impact the shape of molecules. Will certain atoms or lone pairs only be in one of the two positions and thus affect the shape? Axial: On the vertical axis Equatorial: On the plane Cer...
- Sun Nov 29, 2020 2:48 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial vs Equatorial Bonds
- Replies: 11
- Views: 3260
Axial vs Equatorial Bonds
I was having a bit of an issue understanding the differences between axial and equatorial bonds as well as how they impact the shape of molecules. Will certain atoms or lone pairs only be in one of the two positions and thus affect the shape?
- Sun Nov 22, 2020 8:22 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Relationship in Bonding
- Replies: 6
- Views: 441
Re: Electron Relationship in Bonding
Hi! From what I looked up online, many sources said that electron repulsion plays a role in the bond length, however failed to mention to what extent. I would assume that it would not be to a large extent because it was not reviewed in class, but I don't know for sure. From what I looked into, it s...
- Sun Nov 22, 2020 8:05 pm
- Forum: Lewis Structures
- Topic: Lewis acids and Bases
- Replies: 20
- Views: 883
Re: Lewis acids and Bases
I believe in order to distinguish between Lewis Bases and Lewis Acids in a reaction, you need to look at which molecules in the reaction are electron donors and which are electron acceptors. For example, in AlCl 4 - , which is a reaction between AlCl 3 + Cl - , the AlCl 3 is the electron acceptor ma...
- Sun Nov 22, 2020 7:31 pm
- Forum: Dipole Moments
- Topic: Rod-shaped molecules
- Replies: 6
- Views: 296
Re: Rod-shaped molecules
Another example of this I was able to find was between N2 and O2. N2, with a triple bond, sees the atoms being closer together and forming a more spherical shape while O2 has a longer double bond which creates a more rod-like shape. Due to its shape, O2 has a larger surface area and thus two molecul...
- Sun Nov 22, 2020 3:14 pm
- Forum: Dipole Moments
- Topic: Boiling/Melting Points
- Replies: 15
- Views: 1309
Re: Boiling/Melting Points
For melting and boiling points lavelle talked about polarizability being the main factor. So, the common element that add to polarizability is the size of the molecule. So when you compare two elements look at the size. when I mean size atomic radius is a key trend or number of electrons. So if I a...
- Sun Nov 22, 2020 3:05 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Relationship in Bonding
- Replies: 6
- Views: 441
Re: Electron Relationship in Bonding
The more bonds there are, the less lone pairs the atoms will have (i.e. two atoms joined with a triple bond have less lone pairs than two atoms joined in a single bond because more electrons are involved in the bond). Thus, molecules with single bonds have more free electrons, which repel each othe...
- Sun Nov 15, 2020 5:55 pm
- Forum: Dipole Moments
- Topic: Rod-shaped molecules
- Replies: 6
- Views: 296
Re: Rod-shaped molecules
I believe this is due to the rod-shaped structures having a larger surface area and more of the surface area being oriented to interact with each other. It might be a more simple way of looking at it but I immediately thought of stacking plates on top of one another versus placing them side by side,...
- Sun Nov 15, 2020 5:45 pm
- Forum: Dipole Moments
- Topic: Boiling/Melting Points
- Replies: 15
- Views: 1309
Re: Boiling/Melting Points
Understanding that dispersion forces are what affect the boiling and melting point of molecules, I was wondering if someone could clarify how temperature interacts with these dispersion forces. Is it that with a rising temperature, electrons become more excited and thus are more likely to affect nei...
- Sun Nov 15, 2020 5:38 pm
- Forum: Dipole Moments
- Topic: London Dispersion forces
- Replies: 14
- Views: 600
Re: London Dispersion forces
Yes all molecules have London dispersion forces, and it is one of the weakest intermolecular forces. When two molecules come in close proximity they "induce" a partial negative/positive on each other instantaneously making it temporary. I'm unsure if I am correct on this but I believe it ...
- Sun Nov 15, 2020 5:32 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Relationship in Bonding
- Replies: 6
- Views: 441
Electron Relationship in Bonding
I had a question in regards to how electrons interact in double and triple bonds. I understand that their repelling nature results in effects such as Van der Waals forces, so would this repelling play a role in the length of double and triple bonding?
- Sun Nov 15, 2020 5:29 pm
- Forum: Ionic & Covalent Bonds
- Topic: Atomic Radius
- Replies: 38
- Views: 3223
Re: Atomic Radius
I apologize if this has already been asked but I had a little confusion in regards to how Atomic Radius is calculated in ionic bonding. From what I understand, the Atomic Radius is half the distance from the center of a neighboring atom. How does this affect our ability to measure the radii of say N...
- Sun Nov 08, 2020 4:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: Atomic Radius
- Replies: 38
- Views: 3223
Re: Atomic Radius
I apologize if this has already been asked but because neutrons have a neutral charge, and thus they do not "pull-in" the electrons in the orbitals, can we say that they don't affect the atomic radius? For example, Carbon-12 and Carbon-13 would have the same atomic radius?
- Sun Nov 08, 2020 4:33 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 4
- Views: 282
Re: Electron Affinity
I'm unsure of similar electron affinity rules for other periods but I am positive that Nobel Gases are exceptions, given that their outermost orbital is full thus making them more stable and effectively lower in electron affinity.
- Sun Nov 08, 2020 4:22 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Arranging Elements by Electron Affinity
- Replies: 6
- Views: 289
Re: Arranging Elements by Electron Affinity
The reason why atoms that have high electron affinity release energy is because they are so attracted to their electrons that if one of the electrons is taken away energy used to hold that atom is released. Thank you! So presumably for atoms with a low electron affinity, they absorb more energy bec...
- Sun Nov 08, 2020 4:14 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Arranging Elements by Electron Affinity
- Replies: 6
- Views: 289
Re: Arranging Elements by Electron Affinity
I think they release energy because they become more stable once they have attained the electron(s) needed, and stable states have less energy that unstable states. Feel free to correct me if I'm wrong :) This may be a little counterintuitive but I think my confusion is on why adding an electron, t...
- Sun Nov 08, 2020 3:49 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Arranging Elements by Electron Affinity
- Replies: 6
- Views: 289
Re: Arranging Elements by Electron Affinity
Electron affinity increases when it goes to the top and right side of the periodic table. Having a high electron affinity means that it is more likely to gain an electron in which it will release energy because they create bonds. Having a low electron affinity will cause the element to absorb the e...
- Sun Nov 01, 2020 1:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Arranging Elements by Electron Affinity
- Replies: 6
- Views: 289
Arranging Elements by Electron Affinity
I was having a little trouble understanding what exactly a high or low electron affinity meant for an element. From what I understand, elements that desire to fill their outer orbitals will have a higher affinity but I'm not entirely sure how this relates to the absorption or release of energy. Why ...
- Sun Nov 01, 2020 1:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Sapling #24
- Replies: 16
- Views: 548
Re: Sapling #24
I had a bit of an issue with this problem as well. I tried to imagine wrapping each of the examples in a circle to see if they would match up (those that ended at the same side of the line or completely disconnected would not work) as well as eliminating any waves that were not consistent all the wa...
- Sun Nov 01, 2020 1:05 pm
- Forum: Einstein Equation
- Topic: de Broglie and neutrons
- Replies: 8
- Views: 550
Re: de Broglie and neutrons
Yup! Here is a summary of what equations can be used for certain particles. E=hv --> only for photon c=\lambda v --> only for photon E=\frac{1}{2}mv^{2} --> anything that has a mass and velocity (eg: electrons) so NO PHOTONS \lambda = \frac{h}{mv} --> anything that has a mass and velocity so again ...
- Sun Nov 01, 2020 1:00 pm
- Forum: Einstein Equation
- Topic: Week 2-4 Sapling HW Quesiton 25
- Replies: 6
- Views: 493
Re: Week 2-4 Sapling HW Quesiton 25
Photon does not use mass so the E=hv is only used inn that case where mass isn't part of the calculation. Additionally, when looking up the de Broglie equation, one site said it is "used to describe the wave properties of matter, specifically, the wave nature of the electron." So, with th...
- Sun Nov 01, 2020 8:08 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Where should the Rydberg Equation be used?
- Replies: 11
- Views: 483
Re: Where should the Rydberg Equation be used?
I was also a little confused on when to use the Rydberg equation. Thanks for the help. From the examples and the TA's I have asked, it seems like you can use either the Rydberg Equation or E = -hR/n^2 but Dr. Lavelle prefers the latter because it allows us to follow the exact process and placement ...
- Fri Oct 23, 2020 7:58 pm
- Forum: Photoelectric Effect
- Topic: Do we need to know about the Paschen or Brackett series for midterm 1?
- Replies: 7
- Views: 305
Re: Do we need to know about the Paschen or Brackett series for midterm 1?
Dr. Lavelle has said during lecture that we will mostly be dealing with UV, visible, and infrared regions, so that would be Lyman, Balmer, and Paschen series. It might also be good to know that n=4 is the Brackett series Do you think it would also be wise to know the nm measurements for the Paschen...
- Fri Oct 23, 2020 7:01 pm
- Forum: Photoelectric Effect
- Topic: Intensity vs. Frequency
- Replies: 22
- Views: 1918
Re: Intensity vs. Frequency
You're right about the frequency! It's the cycles that pass through within a given time, and is also indicative of the energy, since E=hv. Energy and frequency are proportional, so the higher the frequency, the more energy. Meanwhile, intensity refers to the amount of photons in a light beam, not h...
- Fri Oct 23, 2020 6:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Where should the Rydberg Equation be used?
- Replies: 11
- Views: 483
Re: Where should the Rydberg Equation be used?
I believe the Rydberg Equation is just another way to find the emitted or absorbed light following a quantum level transition and it is derived from the empirical formula. You could use either the empirical formula or Rydberg's Equation but Professor Lavelle prefers that we use the empirical formul...
- Fri Oct 23, 2020 6:01 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Where should the Rydberg Equation be used?
- Replies: 11
- Views: 483
Where should the Rydberg Equation be used?
I am a little confused as to when we are supposed to use the Rydberg Equation vs using the Empirical Equation for Hydrogen. Is the Rydberg Equation simply another method for finding the emitted or absorbed light following a quantum level transition? Or is it more appropriately used when we need to f...
- Fri Oct 23, 2020 4:57 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Lyman vs. Balmer Series
- Replies: 5
- Views: 298
Re: Lyman vs. Balmer Series
Hi! The Lyman and Balmer series just have different wavelength ranges associated with them, and unfortunately I think that's something we just have to memorize. I believe Lyman is 94-122 nm while Balmer is 410-656 nm. You could also figure out what series it is if a type of light is given, as Lyman...
- Fri Oct 16, 2020 3:07 pm
- Forum: Properties of Light
- Topic: Intensity v Energy
- Replies: 18
- Views: 652
Re: Intensity v Energy
I was at first confused by this too, but what I found is that the intensity of light is the amount of photons present. For instance, if you increase the intensity of a light, there will be more photons which will cause the light to become brighter but that does not mean the energy capacity in each ...
- Fri Oct 16, 2020 3:02 pm
- Forum: Properties of Light
- Topic: Energy and Frequency - Continuous or Discrete?
- Replies: 3
- Views: 174
Re: Energy and Frequency - Continuous or Discrete?
I think of it as the frequency is continuous for as long as there is energy. So in the system that is the energy provided, the frequency is continuous. So would you say that light acts like an assembly line where the "packages" (photons) are being continuously moved? The water analogy tha...
- Fri Oct 16, 2020 10:26 am
- Forum: Properties of Light
- Topic: Light Intensity and Photons
- Replies: 8
- Views: 274
Re: Light Intensity and Photons
Light intensity can be defined as photon energy per second per unit area. The intensity of light is also designated by the amplitude of the wave model. Therefore, increasing the number of photons would increase the intensity of the light, but the wavelength and frequency would remain the same since...
- Fri Oct 16, 2020 10:17 am
- Forum: Properties of Light
- Topic: Light Properties: Wave vs Packet
- Replies: 4
- Views: 165
Re: Light Properties: Wave vs Packet
How I thought of it was that when we get down to an extremely small scale (quantum world scale), that's when light behaves like a particle/packets of energy. But in everyday life when we're used to looking at things at a larger scale, that's when light tends to act like a wave. Remember the water a...
- Fri Oct 16, 2020 10:07 am
- Forum: Properties of Light
- Topic: Energy and Frequency - Continuous or Discrete?
- Replies: 3
- Views: 174
Re: Energy and Frequency - Continuous or Discrete?
From what Dr. Lavelle explained in the lecture, it seems that frequencies would be considered continuous for both the particle and wave models (especially helpful when using equations like v=E/h). I found the thread "Are frequencies discrete?" quite helpful if you would like a more detaile...
- Fri Oct 16, 2020 9:43 am
- Forum: Properties of Light
- Topic: Light Properties: Wave vs Packet
- Replies: 4
- Views: 165
Light Properties: Wave vs Packet
So Dr. Lavelle mentioned that light acts both as a wave and at times as a packet of photons, thus the need for both the wave and quantum models. I was a little confused as to how exactly these properties work. Is it that light acts as either a wave or as a packet at certain times; or is it that ligh...
- Sun Oct 11, 2020 6:50 pm
- Forum: Limiting Reactant Calculations
- Topic: Sapling HW 10
- Replies: 9
- Views: 849
Re: Sapling HW 10
You can use the molecular formulas to find the molar mass, but I just searched it up and got molar mass of butanone on the internet. You would only need to know the formulas for the 2-butanone and 3-methyl-3-hexanol since the other product is in excess. To approach the problem, first use the densit...
- Fri Oct 09, 2020 9:31 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Rounding with basic calculator
- Replies: 16
- Views: 959
Re: Rounding with basic calculator
Use the "Ans" key on your calculator whenever possible. We're allowed to use scientific calculators but not graphing calculators, so you should be able to store values. Also, I generally leave at least 5 numbers after each decimal point (for each step) and apply sig figs at the very end. ...
- Fri Oct 09, 2020 9:09 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 327
Re: Mantissa in Logarithms
From what I could find, the mantissa refers to the significant figures after a decimal point. For example, 5.382 would have a mantissa of 0.382. So, assuming we know the value of the logs, we could use the Mantissa to make sure the Significant Figures match if we were to add, subtract, or etc. so we...
- Fri Oct 09, 2020 8:54 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 327
Re: Mantissa in Logarithms
I could see Logarithmic Sig Figs potentially having a role when we starting getting into frequencies and wavelengths, so I imagine this next unit might give us an opportunity to practice using the Mantissa more. I just hope it is straight forward to figure out.
- Fri Oct 09, 2020 3:56 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 327
Re: Mantissa in Logarithms
I'm in the exact same boat, I have never seen it before. I took a screenshot from the bottom of the "Everything You Need to Know About Sig Figs" doc on his website. It seems like you need to know what the value of the log is before you begin then separate the two sides of the decimal point...
- Fri Oct 09, 2020 2:24 pm
- Forum: Significant Figures
- Topic: Mantissa in Logarithms
- Replies: 6
- Views: 327
Mantissa in Logarithms
In these examples of Sig Figs in Logarithms, the term Mantissa is used and unfortunately, I've never encountered this kind of problem. What exactly is the Mantissa and why does the SF of the Mantissa decide the SF in the decimal? Appreciate any help.
- Fri Oct 09, 2020 12:03 pm
- Forum: Student Social/Study Group
- Topic: GroupMe for Lecture 1
- Replies: 2
- Views: 157
Re: GroupMe for Lecture 1
Thank you so much, Zaid! I really appreciate it.
- Thu Oct 08, 2020 8:19 pm
- Forum: Student Social/Study Group
- Topic: GroupMe for Lecture 1
- Replies: 2
- Views: 157
GroupMe for Lecture 1
I apologize if this question has been asked before, but is there a specific GroupMe for Lecture 1, or are there only GroupMe's for specific discussions?