Search found 51 matches
- Wed Dec 04, 2019 12:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final tips
- Replies: 19
- Views: 1080
Re: Final tips
Reading the textbook does help clear up/solidify concepts that we have learned!
- Wed Dec 04, 2019 12:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grades
- Replies: 15
- Views: 1066
Re: Grades
Having 250 points allows you to pass with a C-.
- Wed Dec 04, 2019 12:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry Community Posts
- Replies: 10
- Views: 658
Re: Chemistry Community Posts
I think Dr. Lavelle calculates the points for chemistry community. As long as you have done at least 5 posts per week, you should be fine.
- Wed Dec 04, 2019 12:30 pm
- Forum: Student Social/Study Group
- Topic: readings
- Replies: 13
- Views: 946
Re: readings
Reading the textbook is helpful in clearing up some concepts you may not understand.
- Wed Dec 04, 2019 12:23 pm
- Forum: Student Social/Study Group
- Topic: Preparing for the final
- Replies: 25
- Views: 1271
Re: Preparing for the final
Definitely go to the review sessions! They really break down and explain concepts, and go over practice problems. Reading the textbook is also super helpful.
- Wed Nov 27, 2019 10:45 pm
- Forum: Conjugate Acids & Bases
- Topic: strength of an acid and its conjugate base
- Replies: 3
- Views: 263
Re: strength of an acid and its conjugate base
Yes. As mentioned above, a strong acid's conjugate base is a weak base, and a weak acid's conjugate base is a strong base.
- Wed Nov 27, 2019 9:49 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted acid
- Replies: 9
- Views: 1039
Re: Bronsted acid
HBr is a Bronsted acid because it donates an H+ proton.
- Wed Nov 27, 2019 8:54 pm
- Forum: Lewis Acids & Bases
- Topic: What is the correct definition of a base?
- Replies: 5
- Views: 376
Re: What is the correct definition of a base?
Specifically, a Lewis base is defined as a an electron donor.
- Wed Nov 27, 2019 8:28 pm
- Forum: Lewis Acids & Bases
- Topic: Difference between Bronsted and Lewis Acid?
- Replies: 6
- Views: 1065
Re: Difference between Bronsted and Lewis Acid?
A Lewis acid is defined as an electron acceptor, while a Bronsted acid is defined as a proton donor.
- Wed Nov 27, 2019 1:03 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acids
- Replies: 13
- Views: 1587
Re: Acids
Know the 7 most common acids mentioned above!
- Thu Nov 21, 2019 5:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 6
- Views: 390
Re: Bond Angles
The lone pairs on the central atom would cause the expected bond angles to be slightly less because they repel against electrons in the bonding pairs.
- Thu Nov 21, 2019 4:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: XA2E2
- Replies: 9
- Views: 468
Re: XA2E2
AX2E2 is bent because the lone pairs do affect the positions of the atoms and thus the molecular shape.
- Thu Nov 21, 2019 4:30 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: Ionic
- Replies: 6
- Views: 458
Re: Ionic
Ionic and covalent forces are intramolecular forces.
- Thu Nov 21, 2019 4:17 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: Boiling Points and IMF Strength
- Replies: 6
- Views: 477
Re: Boiling Points and IMF Strength
The more and larger the intermolecular forces, and the stronger they are, the higher the boiling point.
- Thu Nov 21, 2019 3:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 2
- Replies: 7
- Views: 560
Re: Test 2
You can just say "bent" for either!
- Sat Nov 16, 2019 7:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Symmetry and Polarity
- Replies: 13
- Views: 996
Re: Symmetry and Polarity
Drawing the VSEPR models and determining polarity based off of them will give a more accurate answer than determining off of Lewis structures.
- Sat Nov 16, 2019 4:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent or Angular
- Replies: 13
- Views: 1131
Re: Bent or Angular
"Bent" and "angular" refer to the same shape, but I would use "angular" as that is what the book refers to it as.
- Sat Nov 16, 2019 3:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T Shape
- Replies: 7
- Views: 558
Re: T Shape
It is best to be safe and familiarize yourself with all of the shapes.
- Sat Nov 16, 2019 3:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 9
- Views: 549
Re: Bond Angles
The easiest way is to memorize which bond angles go with which shapes. However, do understand the concepts behind why certain bond angles are formed.
- Sat Nov 16, 2019 2:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: All VSEPR structures or just ones from class?
- Replies: 11
- Views: 654
Re: All VSEPR structures or just ones from class?
Memorize all of the shapes just to be safe! Pay attention to how he determined the shapes of the examples covered in class so you know how to do so.
- Wed Nov 13, 2019 8:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 2
- Replies: 15
- Views: 871
Re: Test 2
Test 2 will probably cover material after the midterm, including VSEPR, bond dipole moments, and intermolecular interactions.
- Sat Nov 09, 2019 2:17 am
- Forum: Dipole Moments
- Topic: Hydrogen Bonds
- Replies: 6
- Views: 341
Re: Hydrogen Bonds
Hydrogen is bonded to oxygen, nitrogen, or fluorine in hydrogen bonding. These bonds are strong because they are the most electronegative elements in the periodic table.
- Sat Nov 09, 2019 2:06 am
- Forum: Dipole Moments
- Topic: Dipole Moments
- Replies: 5
- Views: 462
Re: Dipole Moments
A difference in electronegativity results in an unequal sharing of electrons between atoms, resulting in a dipole moment.
- Sat Nov 09, 2019 1:48 am
- Forum: Electronegativity
- Topic: Trend of Electronegativity
- Replies: 22
- Views: 2133
Re: Trend of Electronegativity
Electronegativity increases to the right and up the periodic table because the effective nuclear charges increase.
- Sat Nov 09, 2019 1:26 am
- Forum: Bond Lengths & Energies
- Topic: dissociation energy
- Replies: 5
- Views: 372
Re: dissociation energy
An increase in bond length (a weaker bond) results in a decrease in dissociation energy.
- Sat Nov 09, 2019 1:18 am
- Forum: Dipole Moments
- Topic: Polar
- Replies: 9
- Views: 588
Re: Polar
A difference in electronegativity between the atoms results in a polar molecule.
- Thu Oct 31, 2019 3:35 pm
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 9
- Views: 355
Re: Radicals
A radical is a species with an unpaired electron. You can identify radicals by counting the number of valence electrons and getting an odd number, or by drawing the Lewis structure and seeing the unpaired electron.
- Thu Oct 31, 2019 3:22 pm
- Forum: Electronegativity
- Topic: Radius
- Replies: 13
- Views: 1613
Re: Radius
The greater the electronegativity, the greater the atom's pull on its electrons is. The radius is thus smaller.
- Thu Oct 31, 2019 3:17 pm
- Forum: Lewis Structures
- Topic: Charges on Lewis Structures
- Replies: 7
- Views: 491
Re: Charges on Lewis Structures
Add the electron when counting how many valence electrons are present in the compound. Add the brackets and the negative sign around the structure after you have drawn it.
- Thu Oct 31, 2019 3:10 pm
- Forum: Ionic & Covalent Bonds
- Topic: Valence Electrons?
- Replies: 15
- Views: 1032
Re: Valence Electrons?
bellaha3L wrote:regarding the picture posted, I thought Cl has 7 valence electrons, and the chart says it has 5? I'm pretty sure that chlorine has 7 valence electrons? I could be wrong, unless I'm reading the picture wrong.
I also agree with that; chlorine has 7 valence electrons, but the chart says it has 5.
- Thu Oct 31, 2019 3:08 pm
- Forum: Bond Lengths & Energies
- Topic: Single bond vs double bond
- Replies: 14
- Views: 899
Re: Single bond vs double bond
The numbers describe the length of each bond. Double bonds are shorter than single bonds, and triple bonds are shorter than double bonds.
- Thu Oct 24, 2019 8:33 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v.covalent bonds
- Replies: 7
- Views: 372
Re: Ionic v.covalent bonds
You are correct! Also, in covalent bonds the electrons are shared, while they are not shared in ionic bonds.
- Thu Oct 24, 2019 3:13 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Atomic Radius
- Replies: 18
- Views: 663
Re: Atomic Radius
We probably do not need to calculate the atomic radius, but understand the periodic trend explained in the posts above!
- Thu Oct 24, 2019 3:11 pm
- Forum: Trends in The Periodic Table
- Topic: Location of elements
- Replies: 12
- Views: 719
Re: Location of elements
It will definitely be helpful to know as you will be able to recognize elements' properties and how they interact with other elements; memorize them!
- Thu Oct 24, 2019 2:00 pm
- Forum: Trends in The Periodic Table
- Topic: bond length
- Replies: 9
- Views: 451
Re: bond length
He also mentioned in class that the bond lengths of double bonds are shorter than those of single bonds, and that the bond lengths of triple bonds are shorter than those of double bonds.
- Thu Oct 24, 2019 1:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Energy of spdf orbitals
- Replies: 11
- Views: 400
Re: Energy of spdf orbitals
705198479 wrote:how do I know how many bonds or "dots" go on the ion in the lewis structures
Count the number of valence electrons!
- Sat Oct 19, 2019 2:12 pm
- Forum: Photoelectric Effect
- Topic: Speed of Light
- Replies: 29
- Views: 1616
Re: Speed of Light
The speed of light is a constant. I would use the value given on the equation sheet just to be safe.
- Sat Oct 19, 2019 2:07 pm
- Forum: Properties of Electrons
- Topic: "Exception" in Writing Electron Configurations
- Replies: 4
- Views: 281
Re: "Exception" in Writing Electron Configurations
In class today, Dr. Lavelle discussed an "exception" in writing electron configurations... He said "Half full d5 and full d10 subshells have lower energy". So in the example of Cr, the configuration is written as [Ar]3d5 4s1. Can anyone explain this to me? Why does the 4s shell ...
- Sat Oct 19, 2019 2:02 pm
- Forum: Properties of Electrons
- Topic: electron mass
- Replies: 8
- Views: 325
Re: electron mass
It is provided on the formula sheet, but memorize it just in case!
- Sat Oct 19, 2019 12:28 am
- Forum: Properties of Electrons
- Topic: Using masses of protons, neutrons, and electrons
- Replies: 7
- Views: 319
Re: Using masses of protons, neutrons, and electrons
I don't think we need to memorize the values. Many values are already provided on the formula sheet. However, try to know their masses relative to each other.
- Fri Oct 18, 2019 11:16 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty in Speed [ENDORSED]
- Replies: 31
- Views: 17470
Re: Uncertainty in Speed [ENDORSED]
andrewcj 4I wrote:I think it goes like this:
(p)(
)
(
From here you can plug in (0.01)*(0.05 nm) for
Thank you for the explanation!
- Sat Oct 12, 2019 2:57 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9120
Re: Rydberg equation [ENDORSED]
The Rydberg formula is a mathematical formula used to predict the wavelength of light resulting from an electron moving between energy levels of an atom. Rydberg's findings were combined with Bohr's model in which he found 1/λ = RZ2(1/n12 - 1/n22) where: λ is the wavelength of the photon (wavenumbe...
- Sat Oct 12, 2019 2:55 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 22056
Re: Test 1 [ENDORSED]
pauline 1L wrote:Does anyone know where and when our grades for this class will be updated?
Not sure, but I know you can ask your TA and they will let you know your progress in this class!
- Sat Oct 12, 2019 2:54 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 22056
Re: Test 1 [ENDORSED]
Sean Cheah 3B wrote:curry 1E wrote:Can someone explain what Angstroms are? I was confused on the test on this question.
Angstroms are a unit of length equivalent to 10^(-10) m.
Yup! Bond lengths are typically measured in Angstroms.
- Fri Oct 11, 2019 1:15 pm
- Forum: Administrative Questions and Class Announcements
- Topic: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
- Replies: 53
- Views: 5978
Re: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
Bita Ghanei 1F wrote:Will you be posting the worksheets and their answer keys weekly?
Thank you so much for making these!
She mentioned that she will be posting the worksheets and their answers on this post weekly.
- Fri Oct 11, 2019 1:10 pm
- Forum: Limiting Reactant Calculations
- Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
- Replies: 68
- Views: 7031
Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Show as much work as you can when solving the problems on the test in order to receive as much partial credit as you can!
- Fri Oct 04, 2019 10:39 pm
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 151364
Re: Reading the textbook
Thank you for giving those links! I'll definitely view them to refresh myself on certain topics. I also do recommend reading the textbook because it does go in depth on the topics it covers, and helps solidify concepts you learn.
- Fri Oct 04, 2019 10:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 418320
Re: Advice from a Medical Student [ENDORSED]
Thank you so much for sharing your advice on how to excel in this class! I will definitely keep your tips in mind as I navigate through this course!
- Fri Oct 04, 2019 1:26 pm
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 371567
Re: Final Jitters
Definitely start studying a while before the exams, and do as many practice problems as you can! Working out problems really helps solidify concepts and makes you prepared. Do not try cramming the night before; it never helps.
- Tue Oct 01, 2019 11:02 pm
- Forum: Significant Figures
- Topic: General Rules to Help with Sig Figs
- Replies: 18
- Views: 1057
Re: General Rules to Help with Sig Figs
Thank you so much for listing out the rules! It is very helpful to refer to, especially when working out problems. I also think for #1: 5293 has 4 significant figures.
- Mon Sep 30, 2019 9:50 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student - Part II [ENDORSED]
- Replies: 298
- Views: 270606
Re: Advice from a Medical Student - Part II [ENDORSED]
Thank you so much for sharing your journey from undergraduate to medical school! Your passion for medicine is very inspiring, and exactly what I need to give me motivation to pursue my own career goals!