Search found 64 matches

by Omar Selim 1D
Fri Jan 17, 2020 9:27 am
Forum: Administrative Questions and Class Announcements
Topic: Grading
Replies: 8
Views: 55

Re: Grading

Ask your TA because it varies depending on the TA's preference. Just to be sure, I recommend posting at least 5 times a week.
by Omar Selim 1D
Fri Jan 17, 2020 9:18 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Stress
Replies: 4
Views: 24

Re: Stress

A stress applied to the system is any altercation made that shifts the reaction rates. Stressors include temperature, pressure, the removal or addition of a product or reaction, and the addition of a different reactive sbstance
by Omar Selim 1D
Fri Jan 17, 2020 9:15 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic
Replies: 5
Views: 16

Re: Exothermic

Energy is released when bonds are formed because the atoms go to a lower energy state that is more stable.
by Omar Selim 1D
Fri Jan 17, 2020 9:14 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tips for Test
Replies: 16
Views: 51

Re: Tips for Test

I would read the textbook first as it is the most in depth review of the lecture material you could get. I would then review the lecture notes then do the homework, going over how to approach the homework problems if you get them wrong.
by Omar Selim 1D
Fri Jan 17, 2020 9:12 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Kw
Replies: 16
Views: 51

Re: Kw

Kw = 1.0 *10^-14 is the equilibrium constant for water, which is also defined as Kw = Ka * Kb. The two definitions you gave are interchangeable for the most part
by Omar Selim 1D
Sun Jan 12, 2020 3:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 1 date
Replies: 4
Views: 16

Re: Test 1 date

Dr. Lavelle has the test and exam schedule on the class webpage. For test 1, it will be starting on Tuesday the 21st in your discussion section
by Omar Selim 1D
Sun Jan 12, 2020 3:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Test 1
Replies: 6
Views: 25

Re: Test 1

Test 1 is starting on Jan 21st in your discussion section. Dr. Lavelle has the tests/exam schedule up on the class page
by Omar Selim 1D
Sun Jan 12, 2020 3:50 pm
Forum: Administrative Questions and Class Announcements
Topic: General HW question
Replies: 9
Views: 26

Re: General HW question

The TAs said that it is graded based on a demonstrated effort of answering 5 questions. This is due to the fact that we have access to the solution manual so grading on how many are correct wouldn't be as effective and would dissuade students from actually trying
by Omar Selim 1D
Sun Jan 12, 2020 3:48 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 36
Views: 153

Re: Topics on Test 1

Outline 1 and everything mentioned in the assigned readings/homework assignments/lectures. I believe that test 1 will hold us accountable for everything up until the lecture right before the test
by Omar Selim 1D
Sun Jan 12, 2020 3:46 pm
Forum: Ideal Gases
Topic: Test 1
Replies: 7
Views: 48

Re: Test 1

The best way to determine that is through lectures and the readings on the syllabus. I believe that in the syllabus Dr. Lavelle mentioned that 1 question on every test will be from the homework problems, so those are also a great way of studying.
by Omar Selim 1D
Sun Jan 12, 2020 3:44 pm
Forum: Administrative Questions and Class Announcements
Topic: 14A Final Pickup
Replies: 5
Views: 38

Re: 14A Final Pickup

You'll be able to start picking them up next week from Young Hall. Room 3034 I believe. I'm not sure when the last day to pick them up is but Dr. Lavelle sent out the info in an email a few weeks after the final.
by Omar Selim 1D
Sun Jan 12, 2020 3:42 pm
Forum: Ideal Gases
Topic: Units of Pressure
Replies: 8
Views: 38

Re: Units of Pressure

It is helpful to understand the general proportionalities between the different units of pressure because although we will be getting a conversion sheet, sometimes you may have used a wrong conversion that you could easily identify based on what you would approximate it to be.
by Omar Selim 1D
Wed Dec 04, 2019 6:05 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: 1
Views: 25

Hydrogen bonding

What is a hydrogen bond site? and for hydrogen bonding to occur do both compounds need to contain a hydrogen bonded to F O or N or can you have one compound that involves a bond between H and F O or N and the other compound to just be an F O or N not bonded to a H. For example is the bond between H3...
by Omar Selim 1D
Wed Dec 04, 2019 6:00 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: hybridizing coordination compounds
Replies: 1
Views: 17

hybridizing coordination compounds

Do you hybridize coordination compounds and the ligands they contain? and if so how?
by Omar Selim 1D
Wed Dec 04, 2019 11:15 am
Forum: Naming
Topic: Determining Type of Ligand
Replies: 2
Views: 21

Re: Determining Type of Ligand

There are also certain ones you should commit to memory. Those being:
EDTA (can be hexadente)
Ethylenediamine (can be bidente)
diethylenetriamine(can be tridente)
oxalato (can be bidente)
by Omar Selim 1D
Wed Dec 04, 2019 10:28 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Drawing structures on the final
Replies: 3
Views: 36

Drawing structures on the final

Are we expected to know how to draw different coordination compound structures? do we need to know how to draw chelating coordination compounds?
by Omar Selim 1D
Wed Dec 04, 2019 10:26 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Isomers on the final
Replies: 1
Views: 16

Isomers on the final

to what extent do we have to understand the topic of isomers and the idea of cis vs trans? do we have to be able to identify different types of isomers on the final?
by Omar Selim 1D
Wed Dec 04, 2019 9:12 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Do we need to know the formation constant?
Replies: 1
Views: 27

Re: Do we need to know the formation constant?

It would be helpful to understand the general concept. The equilibrium constant is set up mainly to show what the reaction favors and what the complex's ligands are most likely to be. When analyzing reactions involving the equilibrium constant, it is generally a formation of the products over the re...
by Omar Selim 1D
Sat Nov 30, 2019 10:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 Grades
Replies: 10
Views: 84

Re: Test 2 Grades

Most likely, I would assume, they would be up by Wednesday's lecture in order to give us adequate time to go over them before the final
by Omar Selim 1D
Sat Nov 30, 2019 10:23 pm
Forum: Hybridization
Topic: What to consider for hybridization?
Replies: 3
Views: 25

Re: What to consider for hybridization?

consider lewis structure, orbitals, and electron pairs which also get hybridized
by Omar Selim 1D
Sat Nov 30, 2019 10:21 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pOH
Replies: 2
Views: 24

Re: Calculating pOH

It is material that most likely will be covered in the next lecture but if you are preparing early, it is always better to over prepare than under prepare
by Omar Selim 1D
Sat Nov 30, 2019 10:19 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: What to know for the final
Replies: 8
Views: 62

Re: What to know for the final

I would assume it would not be on the final and that only lecture content and readings will be covered
by Omar Selim 1D
Sat Nov 30, 2019 10:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Content
Replies: 14
Views: 78

Re: Final Exam Content

The final will be cumulative of everything since the beginning of the quarter
by Omar Selim 1D
Sat Nov 30, 2019 10:14 pm
Forum: Student Social/Study Group
Topic: Final Preparation
Replies: 2
Views: 20

Re: Final Preparation

I feel like it would be best to prepare with the mindset that all topics would be covered equally
by Omar Selim 1D
Sun Nov 24, 2019 1:03 pm
Forum: Hybridization
Topic: Strength of sigma and pi bonds
Replies: 8
Views: 32

Re: Strength of sigma and pi bonds

sigma bonds are harder to break than pi bonds because the former are a result of end-to-end bonding while the latter consist of side-to-side bonds
by Omar Selim 1D
Wed Nov 20, 2019 4:04 pm
Forum: Electronegativity
Topic: electronegativity of hydrogen
Replies: 3
Views: 27

Re: electronegativity of hydrogen

Ionic character depends on the difference in electronegativity values. The greater the difference, the more ionic
by Omar Selim 1D
Wed Nov 20, 2019 4:02 pm
Forum: General Science Questions
Topic: Test 2
Replies: 7
Views: 94

Re: Test 2

It all has to be memorized, but i found that ionce you understand 1 row, the rest become easier
by Omar Selim 1D
Wed Nov 20, 2019 2:06 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: Boiling/melting points
Replies: 5
Views: 35

Re: Boiling/melting points

The boiling point and melting point depend on the strength of the bonds. Typically stronger bonds mean a higher boiling/melting point
by Omar Selim 1D
Fri Nov 15, 2019 11:07 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula Notation
Replies: 4
Views: 30

Re: VSEPR Formula Notation

The letters represent: the central atom, bonds, and lone pairs
- A = Central atom
- X = Bonds
- E = Lone pairs
by Omar Selim 1D
Fri Nov 15, 2019 11:05 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs Nonpolar molecules
Replies: 4
Views: 24

Re: Polar vs Nonpolar molecules

The best way to determine whether or not a molecule is non-polar or polar is by analyzing the vectors of electron distribution and pulls depending on electronegativity
by Omar Selim 1D
Fri Nov 15, 2019 11:03 am
Forum: Bond Lengths & Energies
Topic: Bond lengths
Replies: 8
Views: 39

Re: Bond lengths

Because each element has different bond lengths depending on what it is being bonded with, we would probably be given the bond lengths in a question
by Omar Selim 1D
Fri Nov 15, 2019 11:00 am
Forum: Sigma & Pi Bonds
Topic: Hybridization
Replies: 2
Views: 27

Hybridization

We talk about hybridization a lot, but what does it actually mean for certain bonds to be hybridized? and do we hybridize all molecules?
by Omar Selim 1D
Fri Nov 15, 2019 10:58 am
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Viscosity/Surface Tension
Replies: 4
Views: 48

Re: Viscosity/Surface Tension

The result of higher strength intermolecular forces, resulting from the hydrogen bonds between the water molecules, it is harder to break apart those bonds, which causes surface tensions
by Omar Selim 1D
Sun Nov 10, 2019 8:48 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: Polarizability
Replies: 3
Views: 15

Re: Polarizability

For anions, polarizability increases the more electrons it has. For cations, it depends on how small and how charged the ions are
by Omar Selim 1D
Sun Nov 10, 2019 8:46 pm
Forum: Lewis Structures
Topic: Electronegative
Replies: 14
Views: 56

Re: Electronegative

Yes, electronegativity describes the pull of electrons. It increases up and to the right of the periodic table
by Omar Selim 1D
Wed Nov 06, 2019 12:39 pm
Forum: Properties of Light
Topic: De Broglie for Photon?
Replies: 3
Views: 53

Re: De Broglie for Photon?

You don't know the mass of a photon so debroigle's equation would not be applicable
by Omar Selim 1D
Wed Nov 06, 2019 12:37 pm
Forum: Quantum Numbers and The H-Atom
Topic: orbitals vs. subshells
Replies: 4
Views: 36

Re: orbitals vs. subshells

When thinking about what defines an orbital or subshell with respect to quantum numbers, Ml would refer to orbitals while L refers to the s, p, d. f,.. subshells.
by Omar Selim 1D
Wed Oct 30, 2019 12:09 am
Forum: Ionic & Covalent Bonds
Topic: grading
Replies: 5
Views: 62

Re: grading

It is either on My UCLA under "discussions" or the actual lecture
by Omar Selim 1D
Wed Oct 30, 2019 12:07 am
Forum: Octet Exceptions
Topic: aufbau principle
Replies: 8
Views: 67

Re: aufbau principle

There's less energy in the 3rd energy level than the 4th, because of the reality that it takes more energy to maintain stability in the 4th energy level
by Omar Selim 1D
Wed Oct 30, 2019 12:06 am
Forum: Bond Lengths & Energies
Topic: Bond lengths
Replies: 15
Views: 139

Re: Bond lengths

There's no formula but there are very specific lengths for certain bonds that I doubt will be expected knowledge to know on the test
by Omar Selim 1D
Wed Oct 30, 2019 12:04 am
Forum: Ionic & Covalent Bonds
Topic: Valence e-
Replies: 3
Views: 39

Re: Valence e-

It's good practice to understand the whole concept of valence shells, but also understand that the bohr model is not always representative of reality
by Omar Selim 1D
Tue Oct 29, 2019 11:57 pm
Forum: Ionic & Covalent Bonds
Topic: Octet Rule
Replies: 8
Views: 63

Re: Octet Rule

Elements in row 3 and beyond is usually the rule of thumb because they have empty orbitals
by Omar Selim 1D
Wed Oct 23, 2019 12:46 pm
Forum: General Science Questions
Topic: Study Tips
Replies: 13
Views: 129

Re: Study Tips

The homework problems are helpful once you already understand the information so I recommend going to review sessions/ watching helpful chemistry videos then doing the homework problems slowly and making sure you understand why you got a certain answer
by Omar Selim 1D
Wed Oct 23, 2019 12:42 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity Trends
Replies: 5
Views: 41

Re: Electron Affinity Trends

When thinking about electron affinity think about how close the electrons are to the nucleus (where the protons are). Electron affinity increases the closer the electrons are to the nucleus, so it increases as it goes up and to the right
by Omar Selim 1D
Wed Oct 23, 2019 12:38 pm
Forum: Resonance Structures
Topic: polarity
Replies: 1
Views: 49

polarity

Do different resonance structures affect the polarity of molecules?
by Omar Selim 1D
Wed Oct 23, 2019 12:33 pm
Forum: Ionic & Covalent Bonds
Topic: Difference Between Ionic and Covalent
Replies: 8
Views: 293

Re: Difference Between Ionic and Covalent

Ionic bonds occur after electrons have been completely transferred over while covalent bonds are the sharing of ekectrons.
by Omar Selim 1D
Wed Oct 23, 2019 12:30 pm
Forum: Lewis Structures
Topic: Lewis Structure angles
Replies: 3
Views: 30

Re: Lewis Structure angles

Probably try to be as accurate as possible but you don't have to be exact. As long as you have the right attempt, you don't need to use a protractor or anything that specific
by Omar Selim 1D
Wed Oct 16, 2019 12:28 pm
Forum: Properties of Light
Topic: Concept of Rainbows
Replies: 1
Views: 30

Re: Concept of Rainbows

Possibly because the light is not diffracted enough due to the size of the water droplet, or the rainbow could be very small and hard to notice
by Omar Selim 1D
Wed Oct 16, 2019 12:26 pm
Forum: Molarity, Solutions, Dilutions
Topic: What is Molarity?
Replies: 11
Views: 105

Re: What is Molarity?

Molarity is moles/liters. It refers to the concentration of atoms/molecules in a solvent. When something refers to transferring a specific molarity of a substance, it is talking about a certain concentration of that liquid
by Omar Selim 1D
Wed Oct 16, 2019 12:22 pm
Forum: SI Units, Unit Conversions
Topic: Chemistry Grades
Replies: 4
Views: 33

Re: Chemistry Grades

Our TA said grades would be input as soon as assignments go in and they can be checked on MyUCLA
by Omar Selim 1D
Wed Oct 16, 2019 12:19 pm
Forum: DeBroglie Equation
Topic: ionization energy
Replies: 2
Views: 29

Re: ionization energy

Ionization energy is the amount of energy it requires to remove an electron from an atom's valence shell, which is similar to the definition of work function
by Omar Selim 1D
Wed Oct 16, 2019 12:17 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Question regarding definition of molecules
Replies: 5
Views: 61

Re: Question regarding definition of molecules

The constant refers to the amount (6.022*10^23) in a mole of a unit. It could be either a molecule, or an atom as long as it is 1 unit.
by Omar Selim 1D
Sun Oct 13, 2019 8:51 pm
Forum: SI Units, Unit Conversions
Topic: knowing how many sig figs to use
Replies: 17
Views: 126

Re: knowing how many sig figs to use

Sig Figs are important and you should keep them in mind while you're doing a problem but only round at the end
by Omar Selim 1D
Sun Oct 13, 2019 8:49 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 3
Views: 14

Wavelength

Why does a shorter wavelength mean there is more energy?
by Omar Selim 1D
Sun Oct 13, 2019 8:36 pm
Forum: Trends in The Periodic Table
Topic: electronegativity
Replies: 10
Views: 358

Re: electronegativity

Electronegativity is the strength atoms have in puling other electrons to complete their valence shell
by Omar Selim 1D
Sun Oct 13, 2019 8:18 pm
Forum: Photoelectric Effect
Topic: Avogadro's number
Replies: 7
Views: 69

Re: Avogadro's number

Avogadro's number = 6.022 * 10^23 is the number of atoms in a mole. This is used to determine moles of a substance when given the amount of molecules.
by Omar Selim 1D
Sun Oct 13, 2019 8:13 pm
Forum: Properties of Light
Topic: SI units
Replies: 3
Views: 16

Re: SI units

Online there is a chart with all the SI Units you need
by Omar Selim 1D
Sun Oct 13, 2019 8:12 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 4
Views: 36

Re: Photoelectric Effect

It will allow the radiation to reach the intended object without collision
by Omar Selim 1D
Sun Oct 06, 2019 2:28 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molar Mass
Replies: 4
Views: 32

Re: Molar Mass

A periodic table will probably be provided
by Omar Selim 1D
Sun Oct 06, 2019 2:27 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding vs. Multiplying
Replies: 4
Views: 41

Re: Rounding vs. Multiplying

You would just round the 1.1 to 1. A lot of time numbers like that are probably just rounding errors.
by Omar Selim 1D
Sun Oct 06, 2019 2:26 pm
Forum: Empirical & Molecular Formulas
Topic: What decimal place to round to when taking masses from the Periodic Table?
Replies: 19
Views: 178

Re: What decimal place to round to when taking masses from the Periodic Table?

Just make sure to stay consistent. I typically always use 2 decimal places and I would recommend not using less but if you wanna use more that's fine too.
by Omar Selim 1D
Sun Oct 06, 2019 2:24 pm
Forum: Limiting Reactant Calculations
Topic: Finding the limiting reaction
Replies: 3
Views: 22

Re: Finding the limiting reaction

The molar ratio is always important. When you figure out the number of moles you have of each substance, you then use the molar ration to find the actual amount of each substance you need for each amount of yield.
by Omar Selim 1D
Sun Oct 06, 2019 2:21 pm
Forum: Significant Figures
Topic: Significant Figure numbers
Replies: 2
Views: 21

Re: Significant Figure numbers

It depends on the operation. When multiplying/ dividing, the sig figs in your answer must correlate with the least number of sig figs in the operation. When adding/ subtracting, the answer depends on the number of decimal places of the number in the operation with the least amount of decimal places.

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