Search found 52 matches
- Sat Dec 07, 2019 7:44 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelates
- Replies: 5
- Views: 452
Chelates
How do you determine if a coordination compound is a chelate when you're only given the chemical formula, like in mini marshmallow #2?
- Sat Dec 07, 2019 7:33 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: determining number of hydrogen bonding sites
- Replies: 3
- Views: 365
Re: determining number of hydrogen bonding sites
Recall that hydrogen bonds can form when a hydrogen that is bonded to a Nitrogen, Oxygen, or Fluorine is strongly attracted to a Nitrogen, Oxygen, or Fluorine with a lone pair. In problems where it asks you to find how many hydrogen bonding sites there are, you should look for the hydrogens bonded ...
- Sat Dec 07, 2019 6:33 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: determining number of hydrogen bonding sites
- Replies: 3
- Views: 365
determining number of hydrogen bonding sites
How do you determine the number of hydrogen bonding sites? Like the last question on test 2 or 41.d of the marshmallow practice test?
- Sat Dec 07, 2019 6:12 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: determining dentate
- Replies: 1
- Views: 157
determining dentate
How exactly do you determine what dentate a ligand is?
- Sat Dec 07, 2019 6:08 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Ka for strong/weak acids
- Replies: 2
- Views: 203
Re: Ka for strong/weak acids
it is given for a weak acid because we assume that strong acids are 100% dissociable
- Sat Dec 07, 2019 6:06 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: Relative Strength
- Replies: 3
- Views: 327
Re: Relative Strength
ion-dipole is stronger than hydrogen bonding but hydrogen bonding is the strongest of the covalent intermolecular forces
- Sat Dec 07, 2019 6:03 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma Bonds
- Replies: 2
- Views: 232
Re: Sigma Bonds
Sigma bonds are stronger because they overlap to a larger extent than a pi bond.
- Sat Dec 07, 2019 5:59 pm
- Forum: Naming
- Topic: Naming coordination compounds
- Replies: 2
- Views: 179
Naming coordination compounds
Will we be getting the sheet for the ligand names and their charges on the exam? I cannot remember if Dr. Lavelle mentioned it. Thank you!
- Sun Dec 01, 2019 10:42 pm
- Forum: Naming
- Topic: Brackets in Chem. Formula
- Replies: 5
- Views: 323
Re: Brackets in Chem. Formula
The transition metal and all its ligands are contained in the coordination sphere and should be put in brackets.
- Sun Dec 01, 2019 10:40 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma vs. Pi
- Replies: 20
- Views: 1176
Re: Sigma vs. Pi
Sigma bonds are bonded to a greater extent because the orbitals are overlapping each other. This increased surface area of the bond makes it stronger than the side to side pi bonds.
- Sun Dec 01, 2019 10:38 pm
- Forum: General Science Questions
- Topic: Bruincasts
- Replies: 9
- Views: 738
Re: Bruincasts
No, I believe Dr.Lavelle does not bruincast his lectures.
- Sun Dec 01, 2019 10:37 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Notes of November 25
- Replies: 4
- Views: 318
Re: Notes of November 25
Same!! I owe you my life. My email is tinayun0505@gmail.com
- Sun Dec 01, 2019 10:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar vs Non-polar
- Replies: 4
- Views: 273
Re: Polar vs Non-polar
Non polar molecules have dipole moments which are the same magnitude but different directions. Looking at the molecular shapes for non polar molecules, it seems that all of them are symmetrical.
- Fri Nov 22, 2019 9:14 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis v Bronsted v Arrhenius
- Replies: 4
- Views: 280
Re: Lewis v Bronsted v Arrhenius
Bronsted acids and bases deal with the donation and acceptance of a hydrogen ion. Lewis acids and bases deal with the donation and acceptance of an electron. I'm not completely sure about Arrhenius acids and bases but I think it has something to do with hydroxide ions.
- Fri Nov 22, 2019 9:11 pm
- Forum: Dipole Moments
- Topic: Dipole Induced- Dipole Induced
- Replies: 13
- Views: 1096
Re: Dipole Induced- Dipole Induced
Thank you everyone for the clarifications!!
- Fri Nov 22, 2019 9:09 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008764
Re: Post All Chemistry Jokes Here
Michael Jackson be like....
atomic #2, atomic #2
(He He)
atomic #2, atomic #2
(He He)
- Fri Nov 22, 2019 9:06 pm
- Forum: Lewis Acids & Bases
- Topic: Hydronium ion
- Replies: 5
- Views: 258
Re: Hydronium ion
In an acid base reaction, the bronsted acid will donate the H+ to the bronsted base.
- Fri Nov 22, 2019 9:04 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Sphere
- Replies: 6
- Views: 296
Re: Coordination Sphere
The coordination sphere consists of the ligands attached to the central ion.
- Tue Nov 19, 2019 1:42 am
- Forum: Dipole Moments
- Topic: Dipole Induced- Dipole Induced
- Replies: 13
- Views: 1096
Re: Dipole Induced- Dipole Induced
Also, is dipole induced- dipole induced the weakest intermolecular force?
- Tue Nov 19, 2019 1:41 am
- Forum: Dipole Moments
- Topic: Dipole Induced- Dipole Induced
- Replies: 13
- Views: 1096
Dipole Induced- Dipole Induced
Can somebody please give me an example of a dipole induced- dipole induced force? Is it always between two non polar molecules? I wrote in my notes that it is present in all molecules.
Thank you!
Thank you!
- Thu Nov 14, 2019 10:17 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 5
- Views: 301
Re: Lone Pairs
There are many different structures that contain lone pairs. They are not only a bent shape-- this is the shape for a molecule with 2 bonds and one lone pair. It is a good idea to think that lone pairs will generally push the bonded atom away from it due to the fact that it takes up space but also b...
- Thu Nov 14, 2019 9:48 am
- Forum: Bond Lengths & Energies
- Topic: Strongest Bonds
- Replies: 11
- Views: 872
Re: Strongest Bonds
Yes, out of the intermolecular forces for molecules, hydrogen bonding is the strongest.
- Fri Nov 08, 2019 6:23 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: Differences between the intermolecular forces
- Replies: 2
- Views: 263
Differences between the intermolecular forces
Dr. Lavelle uses the terms dipole-dipole, LDF, and van der waals forces interchangeably. In high school I was taught the difference between these forces and was responsible for naming the most prominent kind of intermolecular force in a certain molecule. In this class, do we just consider them inter...
- Fri Nov 08, 2019 6:15 pm
- Forum: Dipole Moments
- Topic: Dipole - Dipole vs. Hydrogen Bonding
- Replies: 7
- Views: 1651
Re: Dipole - Dipole vs. Hydrogen Bonding
Another things that helps is knowing that carbon is “happy” with 4 bonds, nitrogen with 3, oxygen with 2 and fluorine with 1. Meaning that when these elements have these number of bonds, they have a formal charge of zero.
- Fri Nov 08, 2019 6:09 pm
- Forum: Student Social/Study Group
- Topic: Midterm
- Replies: 3
- Views: 270
Re: Midterm
I think the key of the question is that after you have to remember that the hydrocarbon you are solving for has oxygen. In other words, after solving for the moles of all other elements, you must convert these into grams, add the grams up, and subtract from the total grams to find the grams of oxyge...
- Fri Nov 08, 2019 6:06 pm
- Forum: Dipole Moments
- Topic: Hydrogen Bonds
- Replies: 6
- Views: 313
Re: Hydrogen Bonds
In hydrogen bonding there is a hydrogen bonded to either N,O,F. These are some of the most electronegative elements in the periodic table and therefore have great polarizing powers, making their bond with hydrogen very strong.
- Fri Nov 08, 2019 6:00 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008764
Re: Post All Chemistry Jokes Here
Chemistry majors be like I got a chemistry community due this Friday
- Fri Nov 01, 2019 11:56 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions
- Replies: 3
- Views: 134
Re: Exceptions
And a half filled shell is more stable than one that is half filled with an extra electron (regarding ionization energy etc.).
- Fri Nov 01, 2019 11:54 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 2
- Views: 104
Re: Rydberg Equation
I believe for anything to do with electrons and electron emission I think he wants us to use this one En = - h R/n^2 . This is what is on the constants and equations sheet. Yes use this equation and do energy of the final minus energy of the initial to solve for the amount of energy emitted/ absorb...
- Fri Nov 01, 2019 11:53 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008764
Re: Post All Chemistry Jokes Here
nicole-4d wrote:A neutron walks into a bar. He asks the bartender, "How much for a beer?"
The bartender gives him a smile and says, "For you, no charge"
hahahhaha this one made me chuckle
- Fri Nov 01, 2019 11:33 pm
- Forum: Properties of Light
- Topic: Wavelengths
- Replies: 2
- Views: 131
Re: Wavelengths
I don't think we would be responsible for the exact cut offs for the types of radiation but I would just make sure to know the wavelength region for visible light (400-700) and the regions for infrared and UV radiation.
- Fri Nov 01, 2019 11:30 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy (10d on Midterm Review)
- Replies: 3
- Views: 113
Re: Ionization Energy (10d on Midterm Review)
The half filled shell is more stable because with 4 electrons, there is electron to electron repulsion in the first orbital, making the electron easier to remove.
- Fri Oct 25, 2019 9:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Expanded Valence Shells
- Replies: 5
- Views: 198
Re: Expanded Valence Shells
The 3d orbital is not used by these atoms normally, but remains open to be used when bonding. After the 3s and 3p orbitals fill up, the 3D can be used to hold extra electrons during bonding.
- Fri Oct 25, 2019 9:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: Meaning of Brackets
- Replies: 7
- Views: 335
Re: Meaning of Brackets
Brackets are used when citing the electron configuration in the shorthand. You only list the outer orbitals after the last noble gas. You start with the next s orbital after that noble gas.
- Fri Oct 25, 2019 6:09 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: p- and d- orbitals and zero e- density
- Replies: 5
- Views: 209
Re: p- and d- orbitals and zero e- density
Thank you everyone for the clarification!!
- Thu Oct 24, 2019 9:59 am
- Forum: Trends in The Periodic Table
- Topic: Summary of Periodic Trends
- Replies: 7
- Views: 384
Re: Summary of Periodic Trends
Since noble gases already have filled octets, they are extremely stable and do not want it gain another electron, which would make it much more unstable. Therefore, there is almost zero energy released (electron affinity) when an electron is added to a ground state noble gas,
- Wed Oct 23, 2019 12:01 pm
- Forum: Lewis Structures
- Topic: Lewis Structure angles
- Replies: 3
- Views: 245
Re: Lewis Structure angles
I don't think you have to be super meticulous about the angels of the atoms, just the general area would be sufficient. Just remember to place atoms in the way that they are attracted to each other, like the anion next to the cation and not the cation next to the cation or the anion next tot he anio...
- Fri Oct 18, 2019 12:26 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: p- and d- orbitals and zero e- density
- Replies: 5
- Views: 209
Re: p- and d- orbitals and zero e- density
That you for the clarification, it helped a lot! If anyone could explain the zero density stuff, it'd be very helpful. Thank you!
- Fri Oct 18, 2019 12:25 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Hw problem 1E.7 part(c)
- Replies: 1
- Views: 64
Re: Hw problem 1E.7 part(c)
I'm not sure as to why they would place the electrons like that, but I would guess that it is in the ground state. Since theres still 4 electrons total, the atom would have a neutral +0 charge since the nucleus is +4 and the electrons are -4. Because of the neutral charge, I would assume it to be in...
- Fri Oct 18, 2019 11:30 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Why divide h by 4pi?
- Replies: 5
- Views: 329
Re: Why divide h by 4pi?
Though I'm not sure about the derivation of this equation/inequality, the essence of what it is trying to convey is that the more we know about momentum, the less we know about position and vice versa. In other words, we must sacrifice one or the other to obtain accuracy in one. Hope this helps!
- Fri Oct 18, 2019 11:23 am
- Forum: Properties of Electrons
- Topic: Delta
- Replies: 3
- Views: 177
Re: Delta
Whenever a electron goes from a higher energy state to a lower one the electron's energy has decreased and the energy is released as electromagnetic radiation, so we use the negative sign to describe the change in energy. This can be calculated through E=-hR/n^2 and delta E= Ef-Ei. Hope this helps!!
- Fri Oct 18, 2019 11:15 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: p- and d- orbitals and zero e- density
- Replies: 5
- Views: 209
p- and d- orbitals and zero e- density
I'm having some trouble with some of the topics discussed today in lecture. What does Professor Lavelle mean when he says that p- and d- orbitals have nodal planes and therefore have zero e- density and non-symmetric e- distributions? He also mentioned that s- orbitals have no nodal planes so they h...
- Fri Oct 11, 2019 11:55 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Dilutions
- Replies: 10
- Views: 1044
Re: Dilutions
You should use the M initial * v initial = M final * v final. However, that question seems kinda weird because we are solving for initial volume and have the initial molarity and final molarity but no final volume. They need to specify what the final volume of the solution is, so we can properly sol...
- Fri Oct 11, 2019 11:48 pm
- Forum: DeBroglie Equation
- Topic: q 24
- Replies: 2
- Views: 149
Re: q 24
Diffraction patterns prove wavelike properties because it shows that the particles are moving around instead of shooting straight forward. Therefore, this example proves that neutrons have wavelike properties.
- Fri Oct 11, 2019 11:45 pm
- Forum: Photoelectric Effect
- Topic: Wavelengths
- Replies: 4
- Views: 147
Re: Wavelengths
Looking at the speed of light equation, as the wavelength increases, the frequency increases. Seeing that higher frequency light can eject electrons while higher intensity light cannot, this proves the photon properties of light.
- Fri Oct 11, 2019 11:40 pm
- Forum: Properties of Electrons
- Topic: Energy levels
- Replies: 3
- Views: 214
Re: Energy levels
I dont't personally draw out the energy levels, but it might help to do so to figure out which is the inital energy level and which the final. This way you don't get confused when you subtract the energies. Hope this helps!
- Fri Oct 11, 2019 11:37 pm
- Forum: Empirical & Molecular Formulas
- Topic: empirical = molecular?
- Replies: 15
- Views: 905
Re: empirical = molecular?
Yes, if the masses are the same, you would get 1 when you divide the two masses; therefore, the empirical formula or the lowest whole number ratio is the molecular formula.
- Thu Oct 03, 2019 2:33 pm
- Forum: Empirical & Molecular Formulas
- Topic: Molecular Formula
- Replies: 1
- Views: 143
Re: Molecular Formula
Theoretically, you could multiply the percent by the molecular weight since every element would still be in the same ratio, but it would just add an extra step to the calculation. It's usually easier to just assume that the sample is 100 grams since the percentages are portioned out of 100. Even if ...
- Thu Oct 03, 2019 12:10 am
- Forum: Empirical & Molecular Formulas
- Topic: Naming Molecular Compounds
- Replies: 6
- Views: 397
Re: Naming Molecular Compounds
I'm also pretty rusty on nomenclature right now! Though I don't think we will be held responsible for naming on upcoming tests, I would recommend reviewing the common polyatomic ions and their charges as well as the charges for the transition metals (ferric vs ferrous etc.). Also, the common rule is...
- Wed Oct 02, 2019 11:50 pm
- Forum: Empirical & Molecular Formulas
- Topic: Chapter F Problem 15
- Replies: 4
- Views: 488
Re: Chapter F Problem 15
Just assume that the sample is 100 grams and turn all the percents into grams. From there you can convert the grams of elements into moles then divide all the moles by the smallest number of moles. This will give you a relative ratio of each element within the compound. Since the empirical formula i...
- Wed Oct 02, 2019 11:41 pm
- Forum: Limiting Reactant Calculations
- Topic: Cases in which actual product is greater than theoretical?
- Replies: 3
- Views: 170
Re: Cases in which actual product is greater than theoretical?
It would be impossible to have an actual yield greater than the theoretical yield if you used the current amount of reactants. Due to the law of conservation of mass, the amount of products made should be equal to the amount of reactants. However, this is an extremely idealized situation and in a re...
- Wed Oct 02, 2019 11:43 am
- Forum: Molarity, Solutions, Dilutions
- Topic: G.5 Concentration Calculation
- Replies: 4
- Views: 208
Re: G.5 Concentration Calculation
Remember that Na2Co3 will dissociate in a ratio of two Na+ ions to one CO3 polyatomic ion. That way, you know that in a certain molarity sodium carbonate solution, the concentration of pure Na+ ions is doubled. Use the M initial x V initial = M final x V final equation of find the volume needed of o...