We know NH3 is a base, but assuming we didn't know this, how would we know that it would accept protons rather than lose them? Is it because it wants to form NH4, which is a strong acid?
And what are good acids/bases to have memorized? I didn't write down what Dr. Lavelle suggest we know...
Search found 38 matches
- Thu Jun 14, 2018 1:19 am
- Forum: Conjugate Acids & Bases
- Topic: Ammonium [ENDORSED]
- Replies: 1
- Views: 343
- Wed Jun 13, 2018 10:42 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Compounds: Ligands [ENDORSED]
- Replies: 3
- Views: 623
Re: Coordination Compounds: Ligands [ENDORSED]
Is ligand just a special name for the thing bonded to the central atom? Like, what really is their significance?
- Wed Jun 13, 2018 10:38 pm
- Forum: Conjugate Acids & Bases
- Topic: My Understanding
- Replies: 1
- Views: 375
Re: My Understanding
Yes! Our textbook says:
Acid ----donates H+----> conjugate base
Base ----accepts H+----> conjugate acid
Acid ----donates H+----> conjugate base
Base ----accepts H+----> conjugate acid
- Wed Jun 13, 2018 10:36 pm
- Forum: Lewis Structures
- Topic: Breaking the Octet Rule
- Replies: 3
- Views: 472
Re: Breaking the Octet Rule
And just to clarify, the elements that can break the octet rule are H, He, Li, Be, Column 13 and Row 3 and below?
- Sun Jun 03, 2018 11:59 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 2
- Views: 438
Re: Ligands
Will we have to know the differences between ligands? Like in class Dr. Lavelle drew cis-platinum and trans-platinum. Do we have to know keywords like cis and trans in order to draw the right version?
- Sun Jun 03, 2018 11:57 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Hybridization
- Replies: 7
- Views: 859
Re: Hybridization
In the syllabus, for Chapter 4, it says we need to know "hybridization (sp, sp2 sp3, dsp3, d2sp3) and apply this bonding model to inorganic, organic, and biological compounds (molecules, cations, and anions))." I'm just going to try to memorize, unless anyone else has any tips for figuring...
- Sun Jun 03, 2018 11:54 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation number
- Replies: 4
- Views: 592
Re: Oxidation number
I just looked at this link and it seems to cover everything! https://socratic.org/questions/how-do-y ... a-compound
I too am curious about if we'll have to have this memorized for the final...
I too am curious about if we'll have to have this memorized for the final...
- Sun May 27, 2018 11:46 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Meaning
- Replies: 5
- Views: 989
Re: Formal Charge Meaning
Kind of...I think a formal charge of 0 means electrons are equally shared in covalent bonds. I'm not sure if that's the main purpose of formal charge though!
- Sun May 27, 2018 11:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Notes Wed 5/23 and Fri 5/25
- Replies: 2
- Views: 406
Re: Notes Wed 5/23 and Fri 5/25
Thanks so so much! My email is victoriatanaka@g.ucla.edu
- Sun May 27, 2018 4:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Notes Wed 5/23 and Fri 5/25
- Replies: 2
- Views: 406
Notes Wed 5/23 and Fri 5/25
Hi! I wasn't able to attend lecture last Wednesday or Friday because of health reasons. Would any of you be willing to send me the notes for these days? Thanks!
- Sun May 27, 2018 4:47 pm
- Forum: Lewis Structures
- Topic: Central atom and octet rule?
- Replies: 12
- Views: 3082
Re: Central atom and octet rule?
The central atom can have an expanded octet if it appears in Group 3 or below. Their d-orbitals allow for bonding beyond 8 e-. There are also other exceptions to the octect rule, like Group 13 elements, H, He, Li, and Be. The octet rule is a guideline, not a hard fast rule!
- Mon May 21, 2018 9:34 pm
- Forum: Lewis Structures
- Topic: 3.59a
- Replies: 1
- Views: 335
Re: 3.59a
I think it's because O is slightly more electronegative, so it wants to hog that extra e- to get an octet.
- Mon May 21, 2018 8:52 pm
- Forum: Lewis Structures
- Topic: 3.59a
- Replies: 1
- Views: 335
3.59a
For 3.59a you're supposed to draw the Lewis structure for ClO and in the answer key it says the unpaired electron should be on the Cl. But I drew it on the O, which I thought made more sense because then the formal charge of O would be 6 - 5- 1 = 0 and Cl would be 7 - 6 - 1 = 0. In the answer key, O...
- Sun May 20, 2018 2:25 pm
- Forum: DeBroglie Equation
- Topic: De Broglie Wavelength on the Midterm
- Replies: 4
- Views: 729
Re: De Broglie Wavelength on the Midterm
The way I think through these problems is to first write down what I'm given and what is unknown. You're given the velocity of an electron and the mass of an electron is constant. What is unknown is the wavelength of that moving electron. Next, I look for equations that involve my given and unknowns...
- Sun May 20, 2018 2:14 pm
- Forum: Dipole Moments
- Topic: Difference between Dipole-Dipole and Dipole-Induced dipole?
- Replies: 2
- Views: 435
Re: Difference between Dipole-Dipole and Dipole-Induced dipole?
H-F is already a dipole, as H is delta positive and F is delta negative. N triple bond N is naturally equally charged, given N has the N charge as N. But, in the presence of H-Cl, a dipole because H is delta positive and Cl is delta negative, there is a slight pull on the charge of the Ns, making on...
- Sun May 20, 2018 2:10 pm
- Forum: Bond Lengths & Energies
- Topic: Pentane vs. 2-dimethylpropane
- Replies: 3
- Views: 3258
Re: Friday Class
In my notes, I wrote "instantaneous dipoles in two nearby rod-shaped molecules are closer and therefore stronger than those in two nearby spherical molecules." Pentane and 2, 2-Dimethylpropane have the same molecular formula but pentane is rod-shaped. This rod shape is stronger so it's har...
- Sun May 20, 2018 12:23 pm
- Forum: Ionic & Covalent Bonds
- Topic: Phases of molecules
- Replies: 1
- Views: 283
Phases of molecules
In Friday, Dr. Lavelle was explaining that the increasing strength of dispersion forces explains why F2 and Cl2 are gases at room temperature while Br2 is a liquid and I2 is a solid. He also gave other examples. In the periodic table we look at in class, it says the phases of atoms, but in the perio...
- Sun May 20, 2018 12:16 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Relationship in periodic table and polarizability
- Replies: 1
- Views: 1133
Relationship in periodic table and polarizability
Dr. Lavelle said polarizability depends on the number of electrons and the size of an atom or molecule. I think he said polarizability decreases across a period and increases down a group. If I made a mistake, can someone point that out? Also, can someone explain what this means. I don't quite under...
- Sun May 20, 2018 12:07 pm
- Forum: Octet Exceptions
- Topic: Empty d-orbital?
- Replies: 2
- Views: 750
Re: Empty d-orbital?
As far as I understand, an "empty p-orbital" just means that the ground state atom doesn't have electrons in the p-orbital but it is available for bonding. I honestly don't know why this is the case, but I'm just taking it as fact. Sorry if this doesn't really help!
- Sun May 06, 2018 12:27 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger's Equation & Orbitals
- Replies: 3
- Views: 597
Re: Schrodinger's Equation & Orbitals
I'm also confused about this. I have in my notes psi (x, y, z) = Energy psi (x, y, z), but also psi: s, p, d, f. Maybe the x = s, y = p, and z = d?
- Sun May 06, 2018 12:21 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Test 1 Q.1
- Replies: 3
- Views: 508
Re: Test 1 Q.1
And here's my solution for B! For these problems, plugging into the equation M = moles / volume is straightforward, but I think the hardest part is making sure you're using the right value for number of moles. Make sure to calculate the number of moles for the element you want by looking at its rati...
- Sun May 06, 2018 12:07 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Test 1 Q.1
- Replies: 3
- Views: 508
Re: Test 1 Q.1
Here's my solution for A
- Sun May 06, 2018 11:44 am
- Forum: Balancing Chemical Reactions
- Topic: Test 1. Q 3
- Replies: 1
- Views: 340
Re: Test 1. Q 3
Someone told me it's a good plan to keep compunds together that appear on both sides, and my TA told me H20, in most cases, requires an even coefficient. So using those guidelines, I compared PO4 on both sides and multiplied the one on the left my 2. With this, Ca and PO4 are in balance. Now there's...
- Sun Apr 29, 2018 9:33 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.27 [ENDORSED]
- Replies: 4
- Views: 615
Re: 2.27 [ENDORSED]
Orbitals and subshells are not the same thing! Shells are determined by the value of n. Subshells are determined by the value of l (which can go from 0 to the value of n-1). Orbitals are determined by the value of m (which are valued between l and -l). So if you're given n = 4 and l = 1, m can be 1,...
- Sun Apr 29, 2018 4:59 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: # of electrons for a given orbital (homework 2.25)
- Replies: 3
- Views: 480
# of electrons for a given orbital (homework 2.25)
I'm just looking for clarification - is the number of electrons that can occupy a given orbital equal to the number of possible values of m times 2?
- Sun Apr 29, 2018 3:48 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Technicality for 2.19
- Replies: 1
- Views: 132
Technicality for 2.19
The question asks in a) for POSSIBLE values of l but in b) and c) for ALLOWED values for m.
What is the significance of this difference?
What is the significance of this difference?
- Sun Apr 29, 2018 3:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: HW question 2.17 [ENDORSED]
- Replies: 2
- Views: 354
Re: HW question 2.17 [ENDORSED]
m labels the different orbitals of a subshell and its allowed values are l to -l by decrementing l by 1 every time in between (Professor Lavelle did talk about this on Wednesday, so it makes sense that you're confused). So for a), l = 0 and m can only be 0, so there is 1 orbital. In b), l = 2 so m =...
- Sun Apr 22, 2018 9:51 pm
- Forum: Properties of Electrons
- Topic: Circular Standing Waves
- Replies: 2
- Views: 407
Re: Circular Standing Waves
Electrons move around their nucleus in a cloud, so if we think of them moving in a perfect circle (the standing waves oscillating around the circle), there has to be a specific number of wavelengths to fit perfectly in a circle. Because there has to be a specific number of wavelengths around the cir...
- Sun Apr 22, 2018 3:03 pm
- Forum: DeBroglie Equation
- Topic: HW 1.37 [ENDORSED]
- Replies: 6
- Views: 865
Re: HW 1.37 [ENDORSED]
Would the answer be "the wavelength of a proton is x% larger than the wavelength of a neutron"?
- Sun Apr 22, 2018 2:13 pm
- Forum: Photoelectric Effect
- Topic: Homework Problem #33
- Replies: 4
- Views: 404
Re: Homework Problem #33
I'm looking for clarification for 1.33 c. When calculating the E required (in order to calculate the wavelength), you have to combine the E required to eject the e- and the energy of ejecting the e-? How do you know when looking at the question that you need to combine both? I originally solved the ...
- Sun Apr 22, 2018 2:10 pm
- Forum: Properties of Light
- Topic: Electromagnetic Spectrum [ENDORSED]
- Replies: 7
- Views: 786
Re: Electromagnetic Spectrum [ENDORSED]
Does anyone have any tips for remembering the ranges? I know the order of energy for parts of the electromagnetic spectrum but I'm having a hard time learning the ranges of wavelength!
- Sun Apr 15, 2018 9:27 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity [ENDORSED]
- Replies: 3
- Views: 513
Re: Molarity [ENDORSED]
Molarity = moles of solute / volume of solute. Assuming both have 1 Liter of solution (or whatever equal number), the 0.5M solution would have more solvent then the 0.6M solution.
- Sun Apr 15, 2018 9:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Memorizing equations [ENDORSED]
- Replies: 5
- Views: 900
Re: Memorizing equations [ENDORSED]
I also believe the same cover sheet we got for the first test is what we're getting for the rest of the tests! So, if I remember correctly, we didn't get the equation for molarity (and associated Minitial x Vinitial = Mfinal x Vfinal), but it seems to me that this class is very fair about equations ...
- Sun Apr 08, 2018 7:19 pm
- Forum: Empirical & Molecular Formulas
- Topic: Question F17 a
- Replies: 2
- Views: 251
Re: Question F17 a
(This question also applies to part b). Basically I'm asking if what I got as the empirical formula is correct and how to properly order elements if it's not.
- Sun Apr 08, 2018 7:14 pm
- Forum: Empirical & Molecular Formulas
- Topic: Question F17 a
- Replies: 2
- Views: 251
Question F17 a
When i solved for part a, I got C4O4Os. The solutions manual says the answer is OsC4O4. How do I determine the right order to put my answers? I've just been listing the elements in the compound in the order they appear in the question, but this is (potentially?) incorrect in this example!
- Sun Apr 08, 2018 5:11 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding atomic weight (general question) [ENDORSED]
- Replies: 8
- Views: 1089
Rounding atomic weight (general question) [ENDORSED]
I noticed when Prof. Lavelle is calculating molar mass of compounds (or anything involving math), he writes the mass of O as 16 g.mol-1, but H stays 1.008 g.mol-1. Is there a guideline we should follow when rounding atomic masses?
- Sun Apr 08, 2018 3:53 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: E. 35
- Replies: 1
- Views: 237
Re: E. 35
Since the question is asking for a comparison (increase), you have to divide by the original. I did it by comparing what the mass % would be if it remained hydroxyapatite throughout, which would be 100%. Then I divided fluorapatite by hydroxyapatite (504.31/502.32) and found the difference between t...
- Sun Apr 08, 2018 3:08 pm
- Forum: Empirical & Molecular Formulas
- Topic: Naming compounds
- Replies: 4
- Views: 576
Naming compounds
Hi. Does anyone know if we have to know how to name chemical compounds only given their name? Like in question E9, it gives us "magnesium sulfate heptahydrate." I had to look up what the molecular formula would be for it. Do we have to be able to come up with the formulas on our own / does...