## 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: 202

### 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: 143

### 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: 143

### 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: 143

### 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
Replies: 11
Views: 99

### 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: 28

### 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: 105

### 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: 68

### 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: 218

### 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: 61

### 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: 53

### 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: 68

### 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: 200
Views: 141258

### 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: 237

### 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: 110

### 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: 3949

### 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: 110

### 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: 43

### 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: 68

### 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: 164

### 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: 237

### 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: 83

### 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: 37

### 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: 73

### 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
Replies: 4
Views: 145

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: 75

### 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: 64

### 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: 43

### 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: 43

### 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: 28

### 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: 51

### 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: 51

### 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
Topic: Applying Wein's Law
Replies: 3
Views: 165

### 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: 69

### 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: 507

### 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: 200
Views: 141258

### 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: 3949

### Re: Rydberg equation[ENDORSED]

Can someone help me understand why we use the Rydberg equation?
Sat Oct 12, 2019 8:33 pm
Replies: 12
Views: 321

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: 5232

### 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: 62

### 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: 160

### 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: 222

### 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: 133
Views: 17404

### 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...