Search found 43 matches
- Sat Jan 18, 2020 11:52 am
- Forum: Administrative Questions and Class Announcements
- Topic: Study Guide Test One
- Replies: 17
- Views: 703
Re: Study Guide Test One
Use these Learning Outcomes to prepare for Test 1: Outline 1: Chemical Equilibrium https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Chem14B_Outline1_Chemical_Equilibrium.pdf Outline 2: Acids and Bases https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Chem14B_Outline...
- Sat Jan 18, 2020 11:50 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Partial Pressure
- Replies: 19
- Views: 749
Re: Partial Pressure
905289082 wrote:You most likely should be given the partial pressure to complete a problem where you're either solving for Qp or Kp.
What is the difference between Kc and Kp?
- Sat Jan 18, 2020 11:49 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Partial Pressure
- Replies: 19
- Views: 749
Re: Partial Pressure
Why are solids and liquids not included when calculating K values?
- Sat Jan 18, 2020 11:48 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Partial Pressure
- Replies: 19
- Views: 749
Re: Partial Pressure
How do we know when to use K_c and when to use Partial Pressure Notation?
- Sat Jan 18, 2020 11:47 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE and quadratic formula
- Replies: 11
- Views: 597
Re: ICE and quadratic formula
You can make your calculations quicker without having to use the quadratic formula when you approximate x. When Ka or Kb is small enough, x can be assumed to be insignificantly small in comparison to the initial concentration of weak acid or base given. As a result, rather than writing out the init...
- Sat Jan 18, 2020 11:46 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Defining Le Chatelier's Principle
- Replies: 3
- Views: 248
Defining Le Chatelier's Principle
What exactly does Le Chatelier's principle state?
- Sat Jan 18, 2020 11:44 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between K and Q?
- Replies: 11
- Views: 571
Re: Difference between K and Q?
Is the formula always the same for Q and K? I know whether we use Q or K depends on the equilibrium status of the reaction, but we find the values the exact same way otherwise?
- Thu Nov 14, 2019 3:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 9
- Views: 549
Re: Bond Angle
DMuth_1J wrote:So far he has only gone over six, so I would imagine those for sure (especially considering they are considered the basic ones without lone pairs). As he teaches more I believe we will be responsible for all the ones he shows us.
Okay thank you! Do you know how many there will be in total?
- Thu Nov 14, 2019 3:01 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Density
- Replies: 10
- Views: 656
Re: Electron Density
Caitlyn Tran 1G wrote:Yes, I believe that lone pairs of electrons are considered regions of electron density since they influence the molecular shape. Please see the attached image.
Thank you so much! Do you think we are going to have to know all of the shapes?
- Thu Nov 14, 2019 2:46 pm
- Forum: Hybridization
- Topic: Lone Pairs
- Replies: 3
- Views: 255
Re: Lone Pairs
What is a hybridized orbital?
- Thu Nov 14, 2019 2:45 pm
- Forum: Dipole Moments
- Topic: question 3f.5
- Replies: 3
- Views: 209
Re: question 3f.5
Is this always true when a molecule is bigger? How do we know?
- Thu Nov 14, 2019 2:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 9
- Views: 549
Re: Bond Angle
DMuth_1J wrote:The bond angle allows the most space between electrons as is possible. And yes, I believe we have to memorize them.
Do you know which shapes we will have to know?
- Thu Nov 14, 2019 2:42 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 442756
Re: Rusty on High School Chem [ENDORSED]
Just to add on-- Crash Course on Youtube is great for conceptual chemistry and overarching themes, and really helps with understanding the "greater picture" when it comes to some concepts. If you are looking for more step-by-step instruction with worked out examples, I'd highly recommend ...
- Thu Nov 14, 2019 2:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength and Length
- Replies: 18
- Views: 937
Re: Strength and Length
Essentially, the more bonds between two atoms just means that the electron density between the two are much higher than atoms with less bonds. Thus, the higher likelihood of electrons in the middle act to pull the positively charged nuclei of the atoms closer together, making it harder to break. Ca...
- Thu Nov 14, 2019 2:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electrons
- Replies: 9
- Views: 480
Re: Electrons
atoms are more stable when electrons are as far apart as possible because there are less repulsive forces. This is always the case. Think about when you and your friend are pulling on something with all your strength. When one of you lets go the other goes flying. If there were less force pulling, ...
- Thu Nov 14, 2019 2:30 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9154
Re: Rydberg equation [ENDORSED]
Can someone help me understand why we use the Rydberg equation? The Rydberg equation is used to calculate the energy of an electron at a certain principle quantum level of an atom. We'll usually use it in problems where we're asked to calculate the change in energy, frequency, or velocity that occu...
- Thu Nov 14, 2019 2:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electrons
- Replies: 9
- Views: 480
Re: Electrons
Is this always true?
- Thu Nov 14, 2019 2:26 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: Interaction potential energy
- Replies: 3
- Views: 156
Re: Interaction potential energy
can you explain how to find this value?
- Thu Nov 14, 2019 2:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 9
- Views: 549
Re: Bond Angle
Are we going to have to know all of the bond angles for the different shapes?
- Sun Nov 03, 2019 5:13 pm
- Forum: Octet Exceptions
- Topic: Valence Electrons for Transition Metals
- Replies: 4
- Views: 520
Re: Valence Electrons for Transition Metals
Jono S 3D wrote:The same way you would any other atom. It helps to write out the e- configurations in order to do this, and the valence e- will be the number of e- in the outermost layer. Most transition metals have 2 valence e-.
Is this because the d orbital tends to fill either halfway or completely full?
- Sun Nov 03, 2019 5:11 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength and Length
- Replies: 18
- Views: 937
Re: Strength and Length
Simply put, the longer the bond length, the weaker the bond & the shorter the bond length, the stronger the bond.
- Sun Nov 03, 2019 5:09 pm
- Forum: Ionic & Covalent Bonds
- Topic: ionic vs. covalent
- Replies: 7
- Views: 388
Re: ionic vs. covalent
Are ionically bonded atoms always going to have a charge?
- Sun Nov 03, 2019 5:07 pm
- Forum: Lewis Structures
- Topic: structure stability
- Replies: 2
- Views: 168
structure stability
I understand that there are resonance structures but I do not understand what bond order is or how to decide the most stable structure. Can someone help me understand this?
- Sun Nov 03, 2019 5:05 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Shortcut
- Replies: 4
- Views: 269
Re: Formal Charge Shortcut
Can someone please explain to me the concept of formal charge? I am just not quite understanding it. Does anyone have tips or tricks to help comprehend it?
- Sat Oct 26, 2019 3:29 pm
- Forum: Ionic & Covalent Bonds
- Topic: Atomic Radius
- Replies: 4
- Views: 408
Re: Atomic Radius
The more electrons an element has, the larger it will be due to the increasing negative charge and the push of electrons apart as well as the addition of more orbitals i believe.
- Sat Oct 26, 2019 3:26 pm
- Forum: Octet Exceptions
- Topic: Max number of valence e
- Replies: 6
- Views: 657
Re: Max number of valence e
Why do some elements break the rule and carry more electrons in the outermost shells?
- Sat Oct 26, 2019 3:25 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Formula
- Replies: 5
- Views: 314
Re: Formal Charge Formula
We count each shared electron twice, but then in the formula, it is divided by 2 to count for the sharing of the electrons.
- Sat Oct 26, 2019 3:22 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Noble Gases in Electron Configurations
- Replies: 6
- Views: 411
Re: Noble Gases in Electron Configurations
Kinda off-topic, but why are they called "Noble Gases"?
- Sun Oct 20, 2019 9:19 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Noble Gases in Electron Configurations
- Replies: 6
- Views: 411
Re: Noble Gases in Electron Configurations
I believe it is simply for the convenience of shorthand notation.
- Sun Oct 20, 2019 9:16 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: multiple planes in orbitals
- Replies: 2
- Views: 111
multiple planes in orbitals
How do we know which plane (eg. p_x, p_y, p_z) an electron is occupying? And will we need to be able to differentiate these mathematically?
- Sun Oct 20, 2019 9:14 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Focus 1B.25 & 27 Homework
- Replies: 3
- Views: 144
Re: Focus 1B.25 & 27 Homework
aishwarya_atmakuri wrote:The Heisenberg equation states that the product of the uncertainty in momentum times the uncertainty in position has to be greater than or equal to h/4π. This means there is a minimum number of uncertainty at all times.
Are we always calculating the MINIMUM uncertainty?
- Sun Oct 20, 2019 1:22 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Focus 1B.25 & 27 Homework
- Replies: 3
- Views: 144
Focus 1B.25 & 27 Homework
Can someone explain how the Heisenberg EQ works? I understand the plugging in of numbers but want to understand it on a more conceptual level and just can't quite get it.
- Sat Oct 19, 2019 2:54 pm
- Forum: *Black Body Radiation
- Topic: Applying Wein's Law
- Replies: 3
- Views: 292
Applying Wein's Law
Does anyone know how/if we will be applying Wein's law on exams in this class? I am still very uneasy when it comes to black body radiation and understanding it.
- Sat Oct 19, 2019 2:52 pm
- Forum: Einstein Equation
- Topic: Focus 1B.5 Homework.. Electron Volts
- Replies: 2
- Views: 155
Focus 1B.5 Homework.. Electron Volts
Can someone explain to me what the energy 140.511 keV means? I am unsure how to go about converting and understanding electron volts vs. joules
- Sun Oct 13, 2019 1:58 am
- Forum: *Shrodinger Equation
- Topic: Shrodinger Equation
- Replies: 4
- Views: 805
Re: Shrodinger Equation
Will we have to know all of these equations for the midterm/tests?
- Sun Oct 13, 2019 1:54 am
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 442756
Re: Rusty on High School Chem [ENDORSED]
Professor Lavelle's Audio-Visual Focus-Topics are very helpful!
- Sun Oct 13, 2019 1:49 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9154
Re: Rydberg equation [ENDORSED]
Can someone help me understand why we use the Rydberg equation?
- Sat Oct 12, 2019 8:33 pm
- Forum: *Black Body Radiation
- Topic: Black Body Radiation
- Replies: 12
- Views: 753
Re: Black Body Radiation
Why exactly is it called "Black Body" radiation?
- Sat Oct 12, 2019 8:28 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 22880
Re: Test 1 [ENDORSED]
Does anybody know how much the Tests are worth?
- Fri Oct 04, 2019 9:19 am
- Forum: Properties of Light
- Topic: Oscillating Frequency
- Replies: 2
- Views: 158
Oscillating Frequency
Can someone explain how the oscillation blue and red light works?
- Fri Oct 04, 2019 9:09 am
- Forum: Balancing Chemical Reactions
- Topic: How to Balance A Chemical Reaction
- Replies: 7
- Views: 424
Re: How to Balance A Chemical Reaction
Elizabeth_3F wrote:Remember when balancing equations, start with the least number of atoms so you won't get confused!
Is this always true with balancing equations?
- Fri Oct 04, 2019 9:07 am
- Forum: Significant Figures
- Topic: Next Week's Test 1
- Replies: 9
- Views: 574
Re: Next Week's Test 1
Does anyone know exactly what topics we will be tested on for the first test?
- Fri Oct 04, 2019 9:06 am
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 35215
Re: All students read this sig fig post [ENDORSED]
Are we supposed to have the correct sig figs for each step or just the final answer? Thanks! Only the final answer requires the correct number of significant figures but for quizzes there are only a certain amount of points you can lose for significant figures. In others words you do not lose a poi...