Search found 50 matches
- Sat Dec 07, 2019 1:22 am
- Forum: Hybridization
- Topic: Pi bond
- Replies: 10
- Views: 807
Pi bond
Are all pi bonds in the p-orbital, and if so why?
- Sat Dec 07, 2019 1:21 am
- Forum: Lewis Acids & Bases
- Topic: Stronger Base and Stronger Acid
- Replies: 3
- Views: 283
Re: Stronger Base and Stronger Acid
Yeah, in addition to above I’ll use the example from the Marshmallow Review: 1. Atomic Size Basically, the atom with a larger atomic radius makes it a stronger acid: HF v HCl Because F has a smaller atomic radius than Cl, HCl is comparatively more acidic 2. Stability Basically the most stable molecu...
- Sat Dec 07, 2019 1:16 am
- Forum: Naming
- Topic: oxidation number
- Replies: 3
- Views: 216
Re: oxidation number
Yes there are metals that extend beyond 4, although I’m pretty sure we won’t have metals that go beyond 4.
- Sat Dec 07, 2019 1:13 am
- Forum: Lewis Acids & Bases
- Topic: Problem J.9
- Replies: 2
- Views: 245
Re: Problem J.9
I don’t necessarily know if we have to know the names of certain molecules, but on one of the TAs said that usually it will be given to us and it won’t really be cryptic. I think our best bet is to memorize some of the basic ones though.
- Sat Dec 07, 2019 1:11 am
- Forum: Dipole Moments
- Topic: Lone pairs
- Replies: 6
- Views: 369
Re: Lone pairs
Yeah, mostly what I have seen shows that molecules with dipoles are usually polar, however, XeF4, which has lone pairs is actually non polar. So I would just recognize that usually it is heavily dependent on shape and structure. But more on your question, usually if there’s a lone pair, there’s prob...
- Fri Nov 29, 2019 3:36 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Metal Oxidation Number
- Replies: 3
- Views: 264
Metal Oxidation Number
Is there a quick formula or trick that can give me the oxidation state of a metal in a a coordination compound?
- Fri Nov 29, 2019 3:28 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pOH scale
- Replies: 2
- Views: 230
pOH scale
Why is the pH scale the standard, or more used scale? Is it just traditional, or are there more problems that arise from using the pOH scale?
- Fri Nov 29, 2019 3:22 pm
- Forum: Student Social/Study Group
- Topic: Preparing for the final
- Replies: 25
- Views: 1317
Re: Preparing for the final
Yeah I had a similar story too. I didn’t feel like I did well even after going through a bunch of problems and going to a couple sessions. I think the best thing is to ask your TA question-specific questions. Also, just watching OrganicChemistryTutor on YouTube really started to help me. So in addit...
- Fri Nov 29, 2019 3:17 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric Examples
- Replies: 3
- Views: 318
Re: Amphoteric Examples
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&ved=2ahUKEwiUscKRxpDmAhUmIDQIHbCoACcQjRx6BAgBEAQ&url=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FGeneral_Chemistry%2FMap%253A_General_Chemistry_(Petrucci_et_al.)%2F18%253A_Solubility_and_Complex-Ion_E...
- Fri Nov 29, 2019 3:10 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH scale
- Replies: 4
- Views: 336
pH scale
I understand that pH is a concentration, mostly of Hydronium ions (sometimes Hydroxide), however, it goes from 1 to 14. I know that the 14 is equal to 1.0 x 10^-14M (basic), however, can the basic scale extend beyond 14?
- Fri Nov 22, 2019 9:13 pm
- Forum: Naming
- Topic: Exceptions
- Replies: 1
- Views: 114
Exceptions
Are there any exceptions to the naming rules other than the fact that if a coordinate compound is negatively charged we add and -ate? If so, what are they?
- Fri Nov 22, 2019 9:09 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis v Bronsted v Arrhenius
- Replies: 4
- Views: 304
Lewis v Bronsted v Arrhenius
Can someone differentiate between the Lewis base/acid, the Bronsted/Lowry base/acid, and Arrhenius base/acid definitions?
- Fri Nov 22, 2019 9:07 pm
- Forum: Naming
- Topic: Negative charge with Coordination Compound
- Replies: 3
- Views: 231
Negative charge with Coordination Compound
I know that Lavelle talked about how negatively charged coordinate compounds need to have an -ate at the end of their name, however, what about if there is a positively charged coordinate compound? Is this possible and if so, what would be an example?
- Fri Nov 22, 2019 9:01 pm
- Forum: Hybridization
- Topic: Knowing when hybridization occurs
- Replies: 6
- Views: 439
Re: Knowing when hybridization occurs
Basically, if molecule has more than one bonding site (ie usually 3 atoms or a lone pair), hybridization will occur. If you think about it, hybridization is directly related to the number of bonding sites as well: eg. 3 bonding sites= sp2, 4 bonding sites=sp3 and so on and so forth.
- Fri Nov 22, 2019 8:56 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: london forces
- Replies: 9
- Views: 512
Re: london forces
Essentially, if both have LDF as their chiefs intermolecular force, the one that is larger or more polarizable will have a stronger LDF. Another way to push this is to say that the one with a larger molar mass will have stronger London Dispersion Forces. This means that as you go down in group, it w...
- Fri Nov 15, 2019 9:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar vs Nonpolar Example
- Replies: 3
- Views: 343
Re:olar vs Nonpolar Example
Basically, a good example to look up is 2E30. (Yes I know it is an even question, but it is a good example). If you look at it there are three forms of essentially the same element. In the second and third versions, these are the trans and cis versions of the molecules respectively. Essentially in t...
- Fri Nov 15, 2019 9:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: seesaw
- Replies: 9
- Views: 673
Re: seesaw
Essentially this is when there are 4 bonds to a central atom and a lone pair. (AX4E). This can also be called sawhorse though.
- Fri Nov 15, 2019 9:07 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 3
- Views: 193
Re: Bond Angles
If you are referring to substances with the same electronic configuration, this is because the lone pairs of a substance affect the molecular geometry of substance more than atoms. In other words, if you look at rule 4 in the book, it explains that lone pairs repel the other atoms more than atoms an...
- Fri Nov 15, 2019 9:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: London dispersion forces and vander waals
- Replies: 5
- Views: 545
Re: London dispersion forces and vander waals
An example of a van der waal force would be that of a sample of Helium. Essentially, it has a full valence shell and it would have a momentary dipole (one side of atom is positive and the other side is negative), therefore another helium atom could interact with its positive portion to the negative ...
- Fri Nov 15, 2019 8:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Notation
- Replies: 5
- Views: 322
Re: VSEPR Notation
A refers to the central atom, X refers to the number of bonds and E represents lone pairs. However, just remember when you have a radical, you treat that lone electron like a loan pair. So, essentially, E usually represents lone pairs of electrons, however it is important to note that radicals are t...
- Sun Nov 10, 2019 2:03 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Equation?
- Replies: 12
- Views: 575
Re: Formal Charge Equation?
Also, my TA I taught us a really easy way: Valence electrons of element-(number of bonds(lines) + the number of lone electrons(not pairs)). This seemed to work for me and it was fast too. Another trick I learned was that when finding the formal charge for oxygen, if it was double bonded and had two ...
- Sun Nov 10, 2019 1:53 pm
- Forum: Electronegativity
- Topic: Ionization energy of O vs N
- Replies: 6
- Views: 1823
Re: Ionization energy of O vs N
This is the main deviation of the periodic trend of ionization energy increasing to the right and up (fluorine). In this case, nitrogen has a a higher ionization energy than oxygen. The reason is because if you look at the 2p shells of each element, you will see that oxygen has 4 total electrons in ...
- Sun Nov 10, 2019 1:47 pm
- Forum: Octet Exceptions
- Topic: octet exceptions
- Replies: 11
- Views: 610
Re: octet exceptions
There are many octet exceptions. First, H only needs one electron to complete its shell, and this extends to He and a couple of other elements. Next, we have expanded octets which can be any element in the third period which includes P, S, and Cl. Moreover, then we have radicals and biradicals. Alth...
- Sun Nov 10, 2019 1:41 pm
- Forum: Dipole Moments
- Topic: Dipoles Cancelling Out
- Replies: 4
- Views: 301
Dipoles Cancelling Out
When would dipoles cancel out. For instance, CH4 (methane) has two different elements yet all the dipoles “cancel out”; when would I know when other elements have dipoles the cancel out? Would I just have to draw them and evaluate?
- Sun Nov 10, 2019 1:38 pm
- Forum: Dipole Moments
- Topic: Dipoles between the same elements
- Replies: 3
- Views: 282
Dipoles between the same elements
Do elements that are diatomic like O2 or Br2 have dipoles or is it only between molecules?
- Sat Nov 02, 2019 11:12 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Cu and Cr
- Replies: 11
- Views: 597
Cu and Cr
Obviously Copper and Chromium have special electron configurations to maintain stability (3d10 4s1 and 3d5 4s1), however, does this trend continue to the corresponding elements in each group (Molybdenum for Chromium and Silver for Copper)?
- Sat Nov 02, 2019 11:08 am
- Forum: Octet Exceptions
- Topic: Expanded Octet
- Replies: 3
- Views: 185
Expanded Octet
I understand that some elements like S and P can have more than 8 valence electrons, however, is their a way to determine what other elements have the same condition? How would you derive the amount of valence electrons for an element like these? Do we just memorize these exceptions in the table and...
- Sat Nov 02, 2019 11:02 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Understanding Ionic Radius
- Replies: 3
- Views: 281
Understanding Ionic Radius
In the review session, the UAs mentioned three ions that were isoelectronic, meaning they were equal in valence electrons, however, in this case they explained that ionic radius still increases as you move down a group and increases as you go down a period. I’m just confused as to why this is the ca...
- Sat Nov 02, 2019 10:56 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Ionization Energy
- Replies: 3
- Views: 171
Ionization Energy
I know at the review session, the UAs explained that oxygen has a lower ionization energy than nitrogen because nitrogen has a symmetrical arrangement while oxygen does not. Are there any other cases that differ from the general trend of ionization energy increasing to the right and up the table lik...
- Sat Nov 02, 2019 10:53 am
- Forum: Octet Exceptions
- Topic: Odd number of valence electrons
- Replies: 2
- Views: 190
Odd number of valence electrons
I understand that sometimes we are going to be given a molecule and we may not have enough electrons to fill up all the shells. In these cases, with an odd number of electrons, where do we give that extra electron to? In other words, which element gets the extra electron? Does it have to do with ele...
- Sun Oct 27, 2019 5:22 pm
- Forum: Lewis Structures
- Topic: expanded-octet
- Replies: 4
- Views: 192
Re: expanded-octet
Is there a general rule for the d-block elements for the expanded octet, or is it completely variable from element to element? Also, how are we able to derive the expanded octet numbers from these elements?
- Sun Oct 27, 2019 5:12 pm
- Forum: Lewis Structures
- Topic: Reasoning for the octet
- Replies: 3
- Views: 278
Re: Reasoning for the octet
Essentially, you are right, each atom wants to be fully stable, and while there are other factors, such as electrostatic attraction, that ultimately impact bonding, the idea is that each atom wants to fill its outer electron shells to achieve the highest energy level it can. Of course, Hydrogen just...
- Sun Oct 27, 2019 5:03 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability vs. Polarizing Power
- Replies: 3
- Views: 496
Re: Polarizability vs. Polarizing Power
Also, higher polarizable atoms are typically atoms with electrons that are far away from the nucleus, (many shells), and because the electrons are further away, the electron cloud is large and highly polarizable as denoted by the textbook. Also, cations are generally not highly polarizable because t...
- Sun Oct 27, 2019 4:55 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v Covalent Bond
- Replies: 3
- Views: 239
Ionic v Covalent Bond
I understand that there are not truly any definite values that dictate whether a bond is covalent or ionic. However, in the book it says that a good rule of thumb is that an electronegativity difference of two means that the bond has so much ionic character, it is best regarded as ionic. Are there a...
- Sun Oct 27, 2019 4:50 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 6
- Views: 950
Re: Electronegativity
A good rule of thumb when dealing with electronegativity is that as you are going across a period, generally, that has more impact than variance within a group. In other words, that electronegativity is usually closer across a period. With that in mind, even though Chlorine is in the same group as f...
- Sat Oct 19, 2019 7:13 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: P Orbital specifics
- Replies: 4
- Views: 193
P Orbital specifics
I understand that the P orbital has an x, y, and z portion to it depending on the element; however, is the ordering of the orbitals arbitrary? In other words, are we defining the axes first and then deciding that they are x, y or z? Because from different perspectives, the x-axis can be the y-axis a...
- Sat Oct 19, 2019 7:12 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: More Energy levels
- Replies: 1
- Views: 119
More Energy levels
Why is it that when we are dealing with energy levels, as the energy levels increase, they get closer together? Does this also affect our calculations with the Bohr frequency condition or the E=-hR/n^2 formula in any way?
- Sat Oct 19, 2019 7:11 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Applications of Hund’s Rule and Pauli Exclusion Principle
- Replies: 2
- Views: 254
Applications of Hund’s Rule and Pauli Exclusion Principle
Can someone please describe Hund’s Rule and the Pauli Exclusion Principle, and its direct correlation to how it helps us write e- configurations? I am confused on when each one is applicable and not.
- Sat Oct 19, 2019 7:10 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions
- Replies: 2
- Views: 149
Exceptions
Can someone please explain the exceptions to the multi-electron atoms? If someone could use some examples and explanations to describe these special cases, it would be much appreciated.
- Sat Oct 19, 2019 7:09 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: More Orbital Understanding
- Replies: 3
- Views: 173
More Orbital Understanding
I understand that the orbital is a probability field of the highest likelihood of the atoms position, however, is the probability uniform throughout the orbital or is it more likely to be near the nucleus and why?
- Sat Oct 12, 2019 1:47 pm
- Forum: Properties of Electrons
- Topic: Properties of electron being Particle v Wave
- Replies: 3
- Views: 170
Properties of electron being Particle v Wave
I understand that electrons have a duality of having particle-like properties as well as wave-like properties, however, what are the exact examples or properties or that make each side valid? (Atomic Spectra, Photoelectric effect, etc.)
- Sat Oct 12, 2019 1:31 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 41
- Views: 2899
Re: Speed of Light
Unless we are not in a vacuum, the speed of light will stay constant at 3.0 x 10^8 m/s.
- Sat Oct 12, 2019 1:20 pm
- Forum: Properties of Light
- Topic: What exactly is diffraction?
- Replies: 3
- Views: 183
Re: What exactly is diffraction?
Diffraction, in our context, refers to the patterns of high and blow intensities generated by an object in the path of a ray of light. Basically, it is referring to the idea of constructive and destructive interference that shows the wave-like properties of electromagnetic rays.
- Sat Oct 12, 2019 1:14 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Intensity of Light
- Replies: 7
- Views: 230
Re: Photoelectric Effect Intensity of Light
Another important aspect to remember is that each photon interacts with only one electron, and furthermore, if you increase the intensity of the light and if you have enough energy per photon, then more electrons would be emitted.
- Sat Oct 12, 2019 1:06 pm
- Forum: Properties of Electrons
- Topic: Constructive and Destructive Interference
- Replies: 4
- Views: 365
Re: Constructive and Destructive Interference
Another way to think of constructive v destructive waves is that when two waves are in phase, meaning they are both peaks or both troughs at the same moment, you add them. These are constructive waves. Moreover, when two waves are out of phase, meaning one is a trough and the other is a peak at the ...
- Thu Oct 03, 2019 2:31 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Fig Mistakes
- Replies: 17
- Views: 899
Re: Sig Fig Mistakes
The general idea for sig figs is that you are trying to be precise because your calculation is only as accurate as your least accurate measurement. For example for the hypothetical problem find moles of F- in 25.2kg of UF6, it is important to round your answer to three sig figs at the end. The reaso...
- Thu Oct 03, 2019 2:25 pm
- Forum: Balancing Chemical Reactions
- Topic: Naming ionic/ molecular compounds
- Replies: 7
- Views: 520
Re: Naming ionic/ molecular compound
In the periodic table, there are elements (mainly from groups 3-12) that have variable amounts of electrons present. In this case the difference between Iron (II) (ferrous) and Iron (III) (ferric) is that in iron (II), the iron atom has lost two electrons to form Iron (II) and in iron (III) the iron...
- Thu Oct 03, 2019 2:19 pm
- Forum: Empirical & Molecular Formulas
- Topic: Fundamentals F.25
- Replies: 3
- Views: 223
Re: Fundamentals F.25
Basically, on that question you count the figures of each type of element. You then have your molecular formula, which would be C4H6Cl2. That would be your molecular formula. Then, you would divide by the greatest common factor. In essence, divide by 2 and you would get C2H3C6, which would be your e...
- Thu Oct 03, 2019 12:13 am
- Forum: Molarity, Solutions, Dilutions
- Topic: M1V1=M2V2 [ENDORSED]
- Replies: 3
- Views: 729
M1V1=M2V2 [ENDORSED]
I understand that the molarity equation is M1V1=M2V2, however the molarity equation is = to M=n/V. So, basically, I am asking about the idea that shouldn’t the volume cancel out in the M1V1=M2V2. I know my thinking is wrong but I just need a plausible explanation for it.
- Thu Oct 03, 2019 12:05 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Moles
- Replies: 5
- Views: 295
Re: Moles
A key component to remember how to solve for the moles of F- ions in 25.2 kg of UF6 is to understand the idea of the molar ratio. That means that for ever one atom of U there are 6 atoms of F, so your conversion factor is 1 to 6. So, that means you could solve this by first solving for the moles for...