Search found 46 matches
- Thu Dec 05, 2019 9:21 am
- Forum: Amphoteric Compounds
- Topic: Amphoteric Oxides
- Replies: 2
- Views: 175
Re: Amphoteric Oxides
I think they tend to be formed with elements near the metalloids on the periodic table. for example, Al and sometimes As.
- Thu Dec 05, 2019 9:17 am
- 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 disperson
- Replies: 6
- Views: 266
London disperson
just to clarify, all molecules can have london dispersion forces, right? can someone explain why?
- Thu Dec 05, 2019 9:13 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: when to use Heisenberg
- Replies: 2
- Views: 275
Re: when to use Heisenberg
I feel like when you're supposed to use the equation, the question will directly ask you to solve for the uncertainty in position or velocity
- Wed Dec 04, 2019 4:06 pm
- Forum: Lewis Acids & Bases
- Topic: 6A17 - SO3 and As2O3
- Replies: 1
- Views: 232
6A17 - SO3 and As2O3
I don't understand how SO3 is acidic? How could it accept an electron?
Also, how can As2O3 act as both an acid and a base?
Also, how can As2O3 act as both an acid and a base?
- Tue Dec 03, 2019 11:54 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Cations groups 1 and 2
- Replies: 2
- Views: 211
Re: Cations groups 1 and 2
I think it has to do with the low oxidation numbers of group 1 and 2 cations as well as the stability of their anions. It's too difficult for cations with low oxidation states to remove H+.
- Tue Dec 03, 2019 11:46 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Classifying Salts
- Replies: 5
- Views: 314
Re: Classifying Salts
follow up question: wouldn't BaCl be one of the salts that doesn't affect pH because Ba+ is in group 2?
- Tue Dec 03, 2019 7:16 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: acidic trends
- Replies: 3
- Views: 163
acidic trends
Am I correct in saying the strength of an acid is related to electronegativity of the central atom? Can someone elaborate on this?
- Tue Dec 03, 2019 7:14 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6C17 - strength of bases
- Replies: 4
- Views: 220
6C17 - strength of bases
Why is BrO- a stronger base than C17H19O3N?
- Wed Nov 27, 2019 9:51 pm
- Forum: Bronsted Acids & Bases
- Topic: Lewis and Bronsted
- Replies: 4
- Views: 248
Lewis and Bronsted
kind of a stupid question, but I'm just confirming that a Lewis base is the same thing as a Bronsted base, just with different ways of explaining it? in other words, am I correct in saying that it's not possible for a substance to be both a lewis acid and a bronsted base?
- Wed Nov 27, 2019 9:45 pm
- Forum: Bronsted Acids & Bases
- Topic: Writing Chemical Equations
- Replies: 2
- Views: 229
Re: Writing Chemical Equations
if you're talking about neutralization reactions, what I do is make H2O (a lot of the time the hydroxide comes from the base and the other H comes from the acid) and then pair whatever is leftover to make a salt.
Re: Prefixes
I think he was saying that you use those to name the whole coordination compound if the polydentate ligand attached to a central metal atom already has a greek prefix (di-, tri-, etc) in its name.
- Fri Nov 22, 2019 6:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity and melting and boiling points
- Replies: 3
- Views: 489
Re: Polarity and melting and boiling points
To add on: the stronger the intermolecular force, the higher the melting/boiling point (generally speaking)
- Tue Nov 19, 2019 11:21 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Figuring Out Bond Angle
- Replies: 3
- Views: 180
Re: Figuring Out Bond Angle
Also you can't find out quantitatively how much smaller the distorted angle is, you can only determine that it is slightly smaller.
- Tue Nov 19, 2019 11:19 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma and Pi Bonds and Resonance
- Replies: 3
- Views: 112
Re: Sigma and Pi Bonds and Resonance
I don't think so. Each resonant structure should have the same number of sigma and pi bonds, right?
- Mon Nov 18, 2019 11:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape vs Electron Geometry
- Replies: 4
- Views: 382
Re: Molecular Shape vs Electron Geometry
I always think of it as that electron geometry only considers how many regions of electron density there are (i.e. 3 regions = trig planar) while molecular geometry considers whether there are lone pairs or bonded pairs (i.e. 2 bonded pairs, 1 lone pair= bent). also this chart is helpful! https://co...
- Mon Nov 18, 2019 11:21 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: Hydrogen bonding
- Replies: 2
- Views: 203
Hydrogen bonding
Still struggling to understand hydrogen bonding...I think I might be overthinking it but can someone explain in what situation would it occur? And why, for example, does a water molecule have 4 possible places for hydrogen bonds?
- Mon Nov 18, 2019 11:18 pm
- Forum: Hybridization
- Topic: hybridization
- Replies: 11
- Views: 518
Re: hybridization
from what I understand, you look at how many regions of electron density there are and using that number to choose a hybridization scheme. In the end, the number of regions of electron density should equal the number of hybridized orbitals.
- Mon Nov 18, 2019 11:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: polarity
- Replies: 5
- Views: 458
polarity
why are some molecules that are symmetrical (like CH2Cl2) polar? shouldn't the symmetry mean that the dipoles can cancel?
- Mon Nov 18, 2019 11:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: How to know which angles are smaller
- Replies: 8
- Views: 449
Re: How to know which angles are smaller
The lone pair pushes the other regions of electron density closer to each other, making the bond angles smaller. but we can only do this qualitatively, we don't know exactly how much they change.
- Wed Nov 13, 2019 10:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E #5
- Replies: 4
- Views: 230
Re: 2E #5
in general, include leach lone pair as a region of electron density along with the covalent bonds. in this case, like the previous replies said, the shape is bent.
- Wed Nov 13, 2019 10:40 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: What’s the Difference
- Replies: 6
- Views: 520
Re: What’s the Difference
anions are polarizable and the bigger they are, the more polarizable they are. cations have polarizing power that depends on how strongly they can pull the anion's electrons.
- Wed Nov 13, 2019 10:37 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: dipole moment clarification
- Replies: 6
- Views: 325
Re: dipole moment clarification
follow up question, is the permanent dipole part of the definition of a polar molecule? in other words, what defines polar?
- Wed Nov 13, 2019 10:29 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: dipole moment clarification
- Replies: 6
- Views: 325
dipole moment clarification
to clarify, are dipole moments are describing intermolecular forces? and how are intermolecular forces related to polarity?
- Wed Nov 13, 2019 10:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles Exceptions
- Replies: 6
- Views: 326
Bond Angles Exceptions
Dr. Lavelle mentioned that sometimes a bond angle in a tetrahedral will be more or less than 109.5 degrees. when would this be the case?
- Tue Nov 05, 2019 10:07 pm
- Forum: Electronegativity
- Topic: Ionization Energy
- Replies: 3
- Views: 277
Re: Ionization Energy
I don't know if this is the best way to explain it but here's how I think of it: Oxygen has four electrons in the p orbital (one pair and two unpaired). It is relatively easy to remove one of the paired electrons, making its ionization energy lower than nitrogen which is relatively stable with one e...
- Tue Nov 05, 2019 10:01 pm
- Forum: Resonance Structures
- Topic: Formal Charge Question
- Replies: 16
- Views: 812
Re: Formal Charge Question
They just have to sum up to the same overall charge, as far as I know. Not sure if this is what you mean, but some resonant structures are more stable than others due to the formal charges of all the atoms being lower (i.e, all of them being 0 or +1 versus one atom being +2 and others being 0)
- Wed Oct 23, 2019 10:36 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: subshell or orbital?
- Replies: 3
- Views: 150
subshell or orbital?
Is it correct to call it the s,p,d,f orbital or the s,p,d,f subshell? I feel like I've heard it said both ways but which is right...?
- Wed Oct 23, 2019 10:28 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: order
- Replies: 3
- Views: 153
Re: order
I think it's because the d-orbital has lower energy than the s-orbital for some elements
- Wed Oct 23, 2019 10:25 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet Rule
- Replies: 6
- Views: 197
Re: Octet Rule
because they have too few electrons to form an octet
- Wed Oct 23, 2019 10:21 pm
- Forum: Ionic & Covalent Bonds
- Topic: Double Bond vs Single Bond Length
- Replies: 6
- Views: 525
Re: Double Bond vs Single Bond Length
to add on, I think Dr Lavelle said that in actual experimental data, all the bond lengths are the same (1.24A). So the Lewis structure is just a model.
- Wed Oct 23, 2019 1:42 pm
- Forum: Trends in The Periodic Table
- Topic: types of radii
- Replies: 4
- Views: 104
types of radii
I understand the tendency for radii to increase down a group and decrease across a period, but what's the difference between atomic, ionic, and covalent radii? thanks in advance :)
- Thu Oct 17, 2019 1:08 am
- Forum: Properties of Electrons
- Topic: Momentum
- Replies: 11
- Views: 264
Re: Momentum
mass*velocty=momentum(kg*m/s) like the other replies said, it's different from velocity but they're definitely related. if there's no velocity, there also can't be any momentum.
- Thu Oct 17, 2019 12:57 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Ground State [ENDORSED]
- Replies: 5
- Views: 250
Ground State [ENDORSED]
what does it mean for an atom to be in ground state?
- Thu Oct 17, 2019 12:54 am
- Forum: Quantum Numbers and The H-Atom
- Topic: spin up and spin down
- Replies: 7
- Views: 286
Re: spin up and spin down
someone correct me if I'm wrong but I think Lavelle said that the numbers are arbitrary, they're just used to represent one state or the other.
- Thu Oct 17, 2019 12:53 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: how to express answer
- Replies: 6
- Views: 152
Re: how to express answer
pretty sure it depends on what your calculating. like previous response said, you're usually solving for delta(position/velocity/momentum/etc) in which case you use the equal sign.
- Tue Oct 15, 2019 10:36 pm
- Forum: DeBroglie Equation
- Topic: Wavelength of Radiation
- Replies: 3
- Views: 140
Wavelength of Radiation
How would you find the wavelength of the radiation that caused photoejection of the electron (as in question 1B15 part c)? I have the values for energy required to eject the electron, frequency of the radiation, and velocity of the electron emitted. Do you use the c=wavelength*frequency equation or ...
- Thu Oct 10, 2019 1:00 am
- Forum: Photoelectric Effect
- Topic: Kinetic Energy from the Photoelectric Effect
- Replies: 5
- Views: 147
Re: Kinetic Energy from the Photoelectric Effect
It makes the electron move at a certain velocity
- Thu Oct 10, 2019 12:53 am
- Forum: SI Units, Unit Conversions
- Topic: Angstrom
- Replies: 16
- Views: 791
Angstrom
What is an angstrom and do we need to know it for test?
- Thu Oct 10, 2019 12:40 am
- Forum: Limiting Reactant Calculations
- Topic: Net Ionic Equation
- Replies: 6
- Views: 379
Re: Net Ionic Equation
For questions asking about net ionic equation, you do also have to write the full balanced equation in order to calculate percent yield and other information about the products, right?
- Thu Oct 10, 2019 12:37 am
- Forum: Properties of Electrons
- Topic: Rydberg formula clarification
- Replies: 3
- Views: 131
Re: Rydberg formula clarification
I think he meant that Rydberg's is just like a shortcut. It's derived from Bohr's equation but it doesn't help you understand the concepts, so he said to use the other equation, E=-hR/n^2.
- Wed Oct 09, 2019 12:36 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Question L37, Volume of H2O
- Replies: 2
- Views: 133
Question L37, Volume of H2O
Answer to question L37 says, (a) Pipette 31 mL of 16 m HNO3 into a 1.00 L volumetric flask that contains about 800 mL of H2O. Dilute to the mark with H2O. I calculated the 31ml of 16M HNO3, but where does the 800ml come from? How do you find this value? *edit, I know this is not an assigned hw probl...
- Thu Oct 03, 2019 9:36 pm
- Forum: SI Units, Unit Conversions
- Topic: How to format homework
- Replies: 9
- Views: 416
Re: How to format homework
Yes, my TA also said to put your discussion section and it doesn't hurt to put your ID on there too
- Thu Oct 03, 2019 9:33 pm
- Forum: SI Units, Unit Conversions
- Topic: E.7 Chemical Principle 7th edition
- Replies: 4
- Views: 270
Re: E.7 Chemical Principle 7th edition
The above responses are perfect, but for conversion questions in general it may also be helpful to think of Avogadro's number as 6.022 x 10^23 "things" (be it atoms, molecules, etc.) in one mole. From there it makes it easier to see what you need to divide or multiply.
- Thu Oct 03, 2019 9:28 pm
- Forum: Limiting Reactant Calculations
- Topic: Study Strategies/Youtube Videos
- Replies: 14
- Views: 543
Re: Study Strategies/Youtube Videos
I've always liked crash course to help overview conceptual stuff. For specific questions, posting them on here is definitely not a bad idea
- Thu Oct 03, 2019 9:23 pm
- Forum: Limiting Reactant Calculations
- Topic: Calculating Theoretical Yield
- Replies: 9
- Views: 362
Calculating Theoretical Yield
I know that theoretical yield is directly related to the limiting reactant, but how do you know how much of the limiting reactant is used in the reaction? Would it just be the whole amount given in the problem?-- In which case, the theoretical yield would be the same number as the number of grams of...
- Thu Oct 03, 2019 9:10 pm
- Forum: Significant Figures
- Topic: Sig figs in intermediate steps??
- Replies: 5
- Views: 910
Re: Sig figs in intermediate steps??
I was always told not to round until the end when you have a final answer. you can underline the correct amount of sigfigs throughout the problem to help keep track.