## Search found 107 matches

Sun Mar 07, 2021 11:49 am
Forum: Student Social/Study Group
Topic: Fave food
Replies: 183
Views: 740

### Re: Fave food

I haven't had clam chowder in so long, it might not be my favorite food but it's one that I miss the most right now
Sun Mar 07, 2021 11:47 am
Forum: Van't Hoff Equation
Topic: Sapling (5/6) #18
Replies: 3
Views: 32

### Re: Sapling (5/6) #18

One thing that stumped me was that I kept forgetting to convert from kJ to J when calculating for the equilibrium constant. Maybe that could be a place where you miscalculated?
Sun Mar 07, 2021 11:18 am
Forum: Balancing Redox Reactions
Topic: Balancing Reactions Help
Replies: 5
Views: 41

### Re: Balancing Reactions Help

There are some good resources listed under Redox Reactions on Lavelle's 14B site as well!
Sun Mar 07, 2021 11:16 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Combining K's
Replies: 7
Views: 37

### Re: Combining K's

To answer the first question, I know we add things like Gibbs, enthalpy, entropy because they are state functions, which does not depend on the path taken to the final value, whereas rate constant k is not a state function. I'm not too sure how to elaborate on the conceptual aspects behind it, but t...
Sun Mar 07, 2021 10:44 am
Forum: General Rate Laws
Topic: Sapling 9/10 #5
Replies: 9
Views: 45

### Re: Sapling 9/10 #5

For this problem, just apply the coefficient to the [A] and [B] values. For example, halving [A] means 1/2[A] and tripling [B] means 3[B] which means you end up getting 3/2 of the initial rate of .048 Sorry if I'm misunderstanding, but considering that the rate equation is rate = k[A][B] 2 , wouldn...
Wed Mar 03, 2021 6:26 pm
Forum: Administrative Questions and Class Announcements
Topic: LS7a
Replies: 16
Views: 163

### Re: LS7a

I took LS7A over the summer, and while AP Bio definitely helped with some of the more complex knowledge there's quite a bit of information that is covered in typical biology classes in high school, so it probably isn't too difficult. Of the AP Bio material it covered, it had a lot less breadth than ...
Wed Mar 03, 2021 6:15 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Textbook Solution Question 6.57
Replies: 1
Views: 20

### Re: Textbook Solution Question 6.57

They are probably rounding to -12, since there should be 2 significant figures in that calculation. In regards to the second part, I think it's because K refers to the entire reaction, whereas Ka refers to just HF.
Wed Mar 03, 2021 6:06 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Log or ln
Replies: 22
Views: 73

### Re: Log or ln

They are not directly interchangeable but there are ways to change the equation to use either ln or log by changing the constants
Wed Mar 03, 2021 6:04 pm
Forum: Student Social/Study Group
Topic: Fave movie/show
Replies: 66
Views: 326

### Re: Fave movie/show

Aydin Karatas 1F wrote:I recently watched Ride Your Wave and would recommend it. The final scene lives in my head RENT FREE.

Yesssss the final scene made me cry so hard
Wed Mar 03, 2021 5:45 pm
Forum: Zero Order Reactions
Topic: Catalyst/Enzymes and Zero Order
Replies: 4
Views: 31

### Re: Catalyst/Enzymes and Zero Order

Enzymes have a limit to how many reactions it can assist, so once they reach their limit, adding more reactants can't speed up the catalyzing process
Thu Feb 25, 2021 1:47 pm
Forum: Balancing Redox Reactions
Topic: Balancing OH- and H2O
Replies: 4
Views: 24

### Balancing OH- and H2O

In the feedback portion of the Sapling assignments, it says "In basic solution, you can add H2O and OH− as needed to balance oxygen and hydrogen. Or, you can add H2O and H+ as if this were acidic solution, then convert to basic solution by adding OH− to both sides." What does it mean by th...
Thu Feb 25, 2021 11:59 am
Forum: Student Social/Study Group
Topic: Chem 14B Final
Replies: 86
Views: 299

### Re: Chem 14B Final

If you've been studying and doing well for the midterms, you should be good for the final as long as you keep doing the same study process! My main form of studying is going through the textbook problems and the outline concepts.
Thu Feb 25, 2021 11:57 am
Forum: Balancing Redox Reactions
Topic: Week 7&8 Sapling #1
Replies: 2
Views: 34

### Re: Week 7&8 Sapling #1

In this specific case, the K would obey rule #3, while Cl would obey rule 7. As such, the K = +1 oxidation state would take priority!
Thu Feb 25, 2021 11:44 am
Forum: Balancing Redox Reactions
Topic: Sapling W7/8 Q. 5
Replies: 18
Views: 232

### Re: Sapling W7/8 Q. 5

Adalia 3E wrote:Can anyone explain how to balance the H2O and OH- for the first equation? I have the same initial problem but I don't know how to figure out that final equation

Wait just kidding, I've been reading MnO4- as MnO-
Thu Feb 25, 2021 11:43 am
Forum: Balancing Redox Reactions
Topic: Sapling W7/8 Q. 5
Replies: 18
Views: 232

### Re: Sapling W7/8 Q. 5

Can anyone explain how to balance the H2O and OH- for the first equation? I have the same initial problem but I don't know how to figure out that final equation
Sun Feb 21, 2021 1:34 am
Forum: Student Social/Study Group
Topic: Classes for next quarter?
Replies: 162
Views: 811

### Re: Classes for next quarter?

I'm enrolling in Chem14C, LS7B, Math32A, and hopefully Linguistics 1 if I get off the waitlist
Sun Feb 21, 2021 1:26 am
Forum: Ideal Gases
Topic: Ideal Gas vs/ Real Gas
Replies: 10
Views: 44

### Re: Ideal Gas vs/ Real Gas

Real gases also have various intermolecular forces that would alter the calculations. Generally, when referring to the calculations we make, the difference between real gases and ideal gases is negligible
Sun Feb 21, 2021 1:25 am
Forum: Balancing Redox Reactions
Topic: cool acronym
Replies: 25
Views: 131

### Re: cool acronym

I learned the LEO the lion acronym as well! I also think about how reduction = more negative, so more electrons
Wed Feb 17, 2021 11:36 am
Forum: Calculating Work of Expansion
Topic: Textbook 4B.5
Replies: 3
Views: 41

### Re: Textbook 4B.5

In regards to the second question, it might have to do with the fact that they provided the volume in mL rather than L and you didn't adjust for it in your calculations
Wed Feb 17, 2021 11:33 am
Forum: Student Social/Study Group
Topic: Sapling on midterm 2
Replies: 6
Views: 55

### Re: Sapling on midterm 2

I don't think any of the week 7/8 Sapling is going to be on the midterm, either
Tue Feb 09, 2021 4:10 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling #6 Week 5/6
Replies: 4
Views: 34

### Re: Sapling #6 Week 5/6

We use the gas constant when calculating the change in enthalpy relating to a change in temperature
Tue Feb 09, 2021 4:08 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Difference in equations
Replies: 2
Views: 22

### Re: Difference in equations

I'm not too sure myself, but to my understanding the different equations are used depending on what is being changed (i.e. the temperature, the volume, etc.) I think section 4F in the textbook goes over it!
Tue Feb 09, 2021 3:59 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling #6 Week 5/6
Replies: 4
Views: 34

### Re: Sapling #6 Week 5/6

For your first calculation, I think you used the molar heat capacity rather than the gas constant. I think the feedback referring to the sign of the result isn't specific to your answer.
Tue Feb 09, 2021 3:57 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: molar heat capacity
Replies: 9
Views: 81

### Re: molar heat capacity

The molar heat capacity is the amount of energy added to a mol of a substance to cause a change in temperature, whereas enthalpy is the energy of a system
Tue Feb 09, 2021 3:00 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Residual Entropy
Replies: 5
Views: 23

### Re: Residual Entropy

Additionally, the more resonance structures it has means that it has more residual entropy
Tue Feb 09, 2021 2:53 pm
Forum: Ideal Gases
Topic: Chem BL
Replies: 101
Views: 545

### Re: Chem BL

Michael Cardenas 3B wrote:
Constance Newell wrote:I'm taking 14 BL right now.. most of the chemistry is pretty basic so I wouldn't stress out about it... whenever you take it

How hard are the labs?

The labs are alright, since we can't do them in person we generally just interpret data from a lab someone else has done.
Fri Feb 05, 2021 8:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A.9
Replies: 2
Views: 16

### Re: 4A.9

Correct me if I'm wrong, but I think it's negligible which side has the negative in this problem. I looked up some other calorimetry problems, and all the ones I've seen use the same method you did (-qcopper = qwater), so your thinking process is probably correct!
Fri Feb 05, 2021 8:17 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 10 Sapling
Replies: 2
Views: 18

### Re: Question 10 Sapling

If I'm understanding correctly, I think we use the specific heat of ice for the melting of the ice at 0.0C, and then the specific heat of water for the heating of the water.
Fri Feb 05, 2021 8:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sapling Week 3 and 4 #10
Replies: 4
Views: 59

### Re: Sapling Week 3 and 4 #10

For problems like these, you need to use standard enthalpy of fusion to calculate the energy required to melt the ice. Essentially, the equation you'd use would be:
[Heat to melt ice] + [Heat to raise the 47.2g melted ice to the final temperature] = [Heat to cool 373g water to final temperature]
Fri Feb 05, 2021 8:05 pm
Forum: Student Social/Study Group
Topic: Any cool clubs?
Replies: 12
Views: 94

### Re: Any cool clubs?

These all sound super cool! Are there any links or contact information for these clubs?
Fri Feb 05, 2021 6:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sapling Question 18
Replies: 9
Views: 100

### Re: Sapling Question 18

How are we supposed to know the constant-volume molar specific heat? Are we supposed to memorize that?
Tue Jan 26, 2021 10:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: textbook question 6D #5
Replies: 2
Views: 11

### Re: textbook question 6D #5

For these problems, it says to "Refer to Tables 6C.1 and 6C.2 for K a and K b " at the top, so that is probably where you can find the Kb of NH3
Tue Jan 26, 2021 12:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Outline 2 Practice 6.19
Replies: 3
Views: 14

### Re: Outline 2 Practice 6.19

I approached this problem as you said, like a chemical equilibrium problem abiding by Le Chatelier's rule.
Mon Jan 25, 2021 10:00 pm
Forum: Student Social/Study Group
Topic: Favorite Music
Replies: 105
Views: 549

### Re: Favorite Music

I have a hard time focusing when songs have lyrics I can understand, so I've been listening to soundtracks for movies and video games when I'm studying
Mon Jan 25, 2021 9:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Follow through points on the midterm?
Replies: 10
Views: 53

### Re: Follow through points on the midterm?

If I remember correctly, there were some multiple choice questions that offered multiple answers that you could get partial credit for: Ex: 1+2 = _, 3+4 = _ a) 3; 7 b) 3; 2 c) 0; 7 d) 1; 1 where a) would give you full credit, while b) and c) could give you partial credit. Correct me if I'm wrong tho...
Mon Jan 25, 2021 9:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D. 13 Textbook prob
Replies: 1
Views: 13

### Re: 6D. 13 Textbook prob

I think that would only be the case if they were all strong acids/bases. However, since there are weak acids/bases, we need to take into account Ka/Kb as well.
Tue Jan 19, 2021 6:03 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling Week 2 Question 9 & 10
Replies: 4
Views: 39

### Re: Sapling Week 2 Question 9 & 10

I got those problems right, but I don't remember what my process was, so if anyone could explain better it would be appreciated! I think I solved those problems by noting whether the pH was more or less acidic than the pKa. If the pH was more acidic, then the predominant species would be the more ac...
Tue Jan 19, 2021 5:56 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook 6D.5
Replies: 3
Views: 35

### Re: Textbook 6D.5

At the top of the exercises, it says to refer to Tables 6C.1 and 6C.2 for the Ka/Kb, so I assume that's what you'd use!
Tue Jan 19, 2021 5:44 pm
Forum: Ideal Gases
Topic: PV=nRT and Equilibrium
Replies: 12
Views: 88

### Re: PV=nRT and Equilibrium

To my understanding, they are two different topics, but their concepts can overlap in order to solve for certain variables that would require more information to calculate.
Tue Jan 19, 2021 5:40 pm
Forum: Student Social/Study Group
Topic: Midterm Practice
Replies: 9
Views: 54

### Re: Midterm Practice

I would also recommend the video modules on the chemistry website if you'd like more practice!
Tue Jan 19, 2021 5:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Studying for Midterm #1
Replies: 63
Views: 236

### Re: Studying for Midterm #1

I usually study using the textbook problems he assigns, as well as the video modules found on his website!
Wed Jan 13, 2021 10:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Week 2 Sapling #9
Replies: 4
Views: 44

### Re: Week 2 Sapling #9

I don't think we need to use the reverse reaction to calculate concentrations when adding the product, you only need to use ICE to account for the change in concentrations of both sides of the equations.
Wed Jan 13, 2021 10:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5 Week 2
Replies: 4
Views: 52

### Re: Sapling #5 Week 2

So to start out, the equation needed for this problem is B (aq) + H2O (l) <-> BH + (aq) +OH - (aq) , and the formula for Kb = [BH + ][OH - ]/[B]. First, you calculate [OH-] by converting pH -> pOH -> [OH-]. Next, knowing that [OH-] = [BH+], you can plug that into the ...
Wed Jan 13, 2021 10:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Sapling Week 2 #5
Replies: 4
Views: 73

### Re: Sapling Week 2 #5

I kept getting this problem wrong because in the final step, I kept calculating [BH+]/[B] rather than [BH+]/([BH+][B]) like what Claire specified. That might be a place that made you get the incorrect answer
Wed Jan 13, 2021 9:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Net Ionic Equation
Replies: 3
Views: 23

### Re: Net Ionic Equation

To add on one last detail, when making the equation you would raise the concentration of the products/reactants to its coefficient in the equation (ie since Ag+ has a coefficient of 2, it is raised to the 2nd power)
Wed Jan 13, 2021 9:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kb and Ka
Replies: 2
Views: 19

### Re: Kb and Ka

I would assume that the Kb or Ka would be given if necessary, or we have to solve for it ourselves with the given information
Wed Jan 06, 2021 3:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: molar concentrations
Replies: 5
Views: 35

### Re: molar concentrations

There are also problems where you have to calculate the number of moles of gas through stoichiometry before applying the ideal gas law or dividing the moles with the volume.
Wed Jan 06, 2021 3:24 pm
Forum: Ideal Gases
Topic: PV=nRT
Replies: 74
Views: 557

### Re: PV=nRT

You'll probably be using this formula whenever the question asks for one of the variables (pressure, volume, number of moles, or temperature) in relation to a gas and gives information that will help you derive the other variables in order to solve it
Wed Jan 06, 2021 3:19 pm
Forum: Ideal Gases
Topic: T variable in pv=nrt [ENDORSED]
Replies: 38
Views: 364

### Re: T variable in pv=nrt[ENDORSED]

It's probably easier to convert from Celsius to Kelvin so that you only need to memorize one R constant rather than both R constants
Wed Jan 06, 2021 3:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Audio-Visual Assessment 2 Question 29
Replies: 2
Views: 17

### Re: Audio-Visual Assessment 2 Question 29

First, you calculate the initial concentration of BrCl, which should be 1.84x10 -4 M. The initial concentration of the products should both be 0. Next, you calculate the concentration of BrCl when at equilibrium, which is 1.84x10 -4 M * 18.3%. From here, you calculate the change in concentration of ...
Wed Jan 06, 2021 2:53 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 395

### Re: Advice for someone who didn't take 14A with professor Lavelle

The textbook problems helped me the most, especially since if I had problems with them I could either ask on Chem Community or search and see if others had the same problems as I did
Tue Dec 08, 2020 11:20 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: strong or weak acids and bases
Replies: 4
Views: 29

### Re: strong or weak acids and bases

I'm planning on just memorizing the strong acids and bases, since all other acids/bases would be weak
Tue Dec 08, 2020 11:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Content
Replies: 18
Views: 209

### Re: Final Content

I think he mentioned that since quantum was our biggest section, the test would have a bit more quantum questions as well.
Tue Dec 08, 2020 11:06 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: classifying weak/strong acids and bases
Replies: 2
Views: 25

### Re: classifying weak/strong acids and bases

I believe the [H+] = 9.8*10-2 should be in the acidic column, since it is greater than 10-7
Tue Dec 08, 2020 11:04 pm
Forum: Lewis Structures
Topic: N2H4
Replies: 7
Views: 89

### Re: N2H4

I asked my TA about this, she said that Nitrogen is an element that almost never breaks the octet rule in situations like these, and if there were a triple bond not all the hydrogens would be able to bond.
Tue Dec 08, 2020 10:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent v Angular
Replies: 3
Views: 12

### Re: Bent v Angular

Bent and angular is typically interchangeable. The molecule can't be bent if there are only 2 electron groups, so I assume you're asking if we need to differentiate between bent/angular for 3 or 4 electron groups. These are not the same, as the bond angle is different depending on the number of elec...
Sun Nov 29, 2020 3:50 pm
Forum: Hybridization
Topic: Sapling Week 7/8 HW #11
Replies: 13
Views: 106

### Re: Sapling Week 7/8 HW #11

Yes, I think 4 areas of electron density will always be sp3. Correct me if I'm wrong, though!
Sun Nov 29, 2020 3:48 pm
Forum: Hybridization
Topic: Hybridization Lecture Confusion
Replies: 2
Views: 28

### Re: Hybridization Lecture Confusion

I think he brought up the 90 degree example to demonstrate how just looking at atomic orbitals will not bring the right shape, so you'd need to invoke hybridization to create the 4 hybrid orbitals and find the accurate ~109.5 degree angles
Sun Nov 29, 2020 3:35 pm
Forum: Student Social/Study Group
Topic: Making it through Midterm Results
Replies: 13
Views: 170

### Re: Making it through Midterm Results

Is it possible for us to go over which specific questions we got wrong with our TA's? That's usually what helps me study and go over my mistakes but I'm not sure if it's too late by now
Sun Nov 29, 2020 3:33 pm
Forum: Lewis Structures
Topic: sapling number 12
Replies: 2
Views: 47

### Re: sapling number 12

I think your structure was incorrect because it only accounted for 12 of the 14 electrons in the structure (4 H (4 electrons) + 1 C (4 electrons) + 1 O (6 electrons) = 14 electrons)
Sun Nov 29, 2020 3:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial vs Equatorial Bonds
Replies: 11
Views: 140

### Re: Axial vs Equatorial Bonds

Lone pairs tend to be equatorial rather than axial because those will only have two 90 degree bond angles to interact with, while axial ones will have three 90 degree bond angles to interact with and repel from.
Sun Nov 29, 2020 2:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #2
Replies: 2
Views: 35

### Re: Sapling #2

This shape would be linear because the two bonds with X would be axial while the 3 lone pairs would be equatorial, thus making the bonds have a 180 degree bond angle and having the long pairs form a triangle around the central atom on the opposite plane of the axis.
Sun Nov 22, 2020 10:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Scores
Replies: 28
Views: 260

### Re: Midterm 2 Scores

I did alright on midterm 1, but I'm also pretty nervous about my midterm 2 scores so I'm hoping we get our grades as soon as possible
Sun Nov 22, 2020 10:04 pm
Forum: Lewis Structures
Topic: Week 8 Sapling Homework #13
Replies: 3
Views: 36

### Re: Week 8 Sapling Homework #13

I started with looking at a single carbon atom, since they all have the same bond structure, and then counting how many bonds it had connected to it. Then, I looked at the shape they made when branching off from the carbon atom.
Sun Nov 22, 2020 9:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #1
Replies: 6
Views: 72

### Re: Sapling #1

The carbonate ion has no lone pairs, while the sulfite ion has one lone pair
Sun Nov 22, 2020 9:48 pm
Forum: Dipole Moments
Topic: Boiling/Melting Points
Replies: 15
Views: 173

### Re: Boiling/Melting Points

One way to think about it is that going from solid -> liquid -> gas requires energy to separate the molecules. Molecules with greater intermolecular forces would require more energy (heat) to separate, and thus have a higher boiling/vaporizing point.
Sun Nov 22, 2020 9:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity from Lewis Structures
Replies: 6
Views: 48

### Re: Polarity from Lewis Structures

We also take into account the symmetricalness of the Lewis structure when determining its polarity
Tue Nov 17, 2020 8:45 pm
Forum: Electronegativity
Topic: 2F.5 part c
Replies: 4
Views: 20

### Re: 2F.5 part c

They do have dipole-dipole interactions, but the differences in their dipole-dipole interactions is not as great as the differences in their London Dispersion interactions
Tue Nov 17, 2020 5:43 pm
Forum: Administrative Questions and Class Announcements
Topic: 50% Need for a C-? How much is need for an A then?
Replies: 5
Views: 77

### Re: 50% Need for a C-? How much is need for an A then?

If you're talking about overall grade, I've heard that Lavelle usually adjusts the grades at the end of quarter in relation to the average, but I don't know if he'll do it this quarter.
Tue Nov 17, 2020 5:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B Lectures
Replies: 15
Views: 151

### Re: Chem 14B Lectures

How will Chem 14BL classes be structured? Will those be asynchronous as well?
Tue Nov 17, 2020 5:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: ElectronConfigurations
Replies: 3
Views: 17

### Re: ElectronConfigurations

I think they would both be correct, although it would be much easier to write [Kr] for both your sake and the grader's sake
Tue Nov 17, 2020 5:30 pm
Forum: Electronegativity
Topic: 2F.5 part c
Replies: 4
Views: 20

### Re: 2F.5 part c

I think the differences in the number of electrons between the CHI3 and CHF3 atoms have a greater effect on intermolecular forces than the differences in electronegativity
Tue Nov 17, 2020 5:24 pm
Forum: Ionic & Covalent Bonds
Topic: vapor pressure (question 3.F19 part B)
Replies: 1
Views: 7

### Re: vapor pressure (question 3.F19 part B)

The vapor pressure is the pressure that the evaporated form exerts on the liquid form while in equilibrium. As the boiling point decreases, vapor pressure increases because there are more vapor molecules at a lower boiling point that are producing the greater pressure. Likewise, as the boiling point...
Sun Nov 08, 2020 2:35 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Sapling Week 5-6 # 12
Replies: 4
Views: 46

### Re: Sapling Week 5-6 # 12

I don't think he's covered oxidation numbers just yet, but it would be safer to read about it in the textbook in case he doesn't cover it.
Sun Nov 08, 2020 2:32 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation number?
Replies: 8
Views: 84

### Re: Oxidation number?

I don't think he's covered the specific rules for oxidation numbers just yet, but I do remember O is always an -2 oxidation number unless it is in a O2 molecule. Otherwise, I think we'll have to wait until we get to that unit.
Sun Nov 08, 2020 2:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Textbook question 2A.9 (omit c and d)
Replies: 2
Views: 14

### Re: Textbook question 2A.9 (omit c and d)

First, I'd add 2 electrons to the electron configuration so I can have the ground-state electron configuration of M rather than the M2+ ion. I'd then find the element that corresponds with the ground-state of this new electron configuration. I'm not sure if this is the proper way to do it, but that'...
Sun Nov 08, 2020 2:24 pm
Forum: Electronegativity
Topic: Atom size
Replies: 22
Views: 1047

### Re: Atom size

Electronegativity does not cause changes in atomic size, nor does atomic size cause changes in electronegativity, but they have similar trends because they were both affected by the attractive forces between the electrons and nucleus.
Sun Nov 08, 2020 2:20 pm
Forum: Dipole Moments
Topic: Sapling #19
Replies: 3
Views: 16

### Re: Sapling #19

I'm not sure either, I would have thought it would be dipole-dipole and hydrogen bonding as well.
Wed Nov 04, 2020 8:57 pm
Forum: Lewis Structures
Topic: Lewis structure for sapling
Replies: 3
Views: 24

### Re: Lewis structure for sapling

One problem is likely that you put too many bonds on the center C atom. That might be a good place to start!
Wed Nov 04, 2020 2:20 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B Enrollment
Replies: 27
Views: 366

### Re: Chem 14B Enrollment

While it's true that you might still be able to enroll in 14B, another factor also depends on the schedule you want to have. You might want to use your first pass on classes that you want a very specific discussion/lecture time even if there are spots available at other times.
Wed Nov 04, 2020 2:15 pm
Forum: Ionic & Covalent Bonds
Topic: London Dispersion Forces
Replies: 5
Views: 21

### Re: London Dispersion Forces

To my knowledge, all molecules will have London Dispersion Forces because they are the forces that arise due to the random movement of electrons within the molecule.
Wed Nov 04, 2020 2:11 pm
Forum: Student Social/Study Group
Topic: Favorite TV shows
Replies: 212
Views: 1847

### Re: Favorite TV shows

If you liked Castlevania, you might like Seis Manos as well, as it's animated by the same studio!
Wed Nov 04, 2020 2:04 pm
Forum: Administrative Questions and Class Announcements
Topic: missing discussion
Replies: 8
Views: 75

### Re: missing discussion

To my knowledge, you probably won't receive a grade penalty for being absent to a discussion, but I'm not sure how your TA will help you with the information you missed during that discussion. Hope they respond to you soon!
Sun Oct 25, 2020 2:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm calculator policy
Replies: 10
Views: 95

### Midterm calculator policy

Are there any restrictions to the calculator we can use?
Sun Oct 25, 2020 2:42 pm
Forum: Einstein Equation
Topic: Scratch paper during the exam
Replies: 19
Views: 158

### Re: Scratch paper during the exam

We should be allowed to write on the equations sheet and the periodic table, but it would be safer to check with your TA's first.
Sun Oct 25, 2020 2:37 pm
Forum: SI Units, Unit Conversions
Topic: Other conversions for the Midterm
Replies: 4
Views: 67

### Re: Other conversions for the Midterm

It's probably best to have the most common prefixes memorized for the exam (i.e. kilo-, centi-, milli-, etc) for conversions, otherwise unit conversions tend to be pretty self-explanatory based on the given units and equations
Sun Oct 25, 2020 2:26 pm
Forum: *Particle in a Box
Topic: Energy Equations
Replies: 9
Views: 201

### Re: Energy Equations

The equation you use is based on both the information you are given and what you are planning to solve for
Sun Oct 25, 2020 2:24 pm
Forum: Student Social/Study Group
Topic: Midterm Question
Replies: 9
Views: 96

### Re: Midterm Question

From what I've seen, it's best to remember the wavelength range for visible light and the general order of the spectrum, but I don't think we need to memorize every single range for every single type of electromagnetic radiation
Sun Oct 25, 2020 2:22 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1513

### Re: How are you studying?

For me reading through concepts and listening to lectures isn't as helpful as just doing practice textbook and module problems. I find it easier to remember things after applying them to problems myself
Sun Oct 25, 2020 2:14 pm
Forum: Student Social/Study Group
Topic: Midterm Question
Replies: 9
Views: 96

### Re: Midterm Question

https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
https://lavelle.chem.ucla.edu/wp-conten ... _IUPAC.pdf
These are the two documents he sent, in case anyone didn't get the email!
Wed Oct 21, 2020 2:28 pm
Forum: DeBroglie Equation
Topic: worked example
Replies: 5
Views: 72

### Re: worked example

How will we know what constants/formulas will be provided on the formula sheets and which we will need to memorize leading up to the midterm?
Wed Oct 21, 2020 2:22 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework problem #8
Replies: 3
Views: 60

### Re: Homework problem #8

My understanding is that the Lymann series is in the UV region due to the high change in energy when returning to n=1, whereas the Balmer series is in the visible light region
Wed Oct 21, 2020 1:07 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module #29
Replies: 9
Views: 91

### Re: Photoelectric Effect Module #29

Before you divide h by v, I think you need to add together the kinetic energy of the ejected electron (Eexcess) with the kinetic energy needed to remove that electron (Ethreshold) to get the energy of the incident light, then find its frequency
Wed Oct 21, 2020 12:12 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module #29
Replies: 3
Views: 40

### Re: Photoelectric Effect Module #29

Like I said on your post about #30, not only do you have to convert from kJ to J, you also have to convert from mol to electrons using Avogadro's number
Wed Oct 21, 2020 12:11 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module #29
Replies: 9
Views: 91

### Re: Photoelectric Effect Module #29

I got this wrong as well, but I think you made the same mistake I did. I think you need to convert the work function from kJ/mol to J/electron, then continue your calculations from there
Mon Oct 19, 2020 2:00 pm
Forum: Properties of Light
Topic: Properties of photons
Replies: 4
Views: 39

### Properties of photons

How do photons have momentum but no mass? Not sure if I'm understanding the lecture properly
Wed Oct 14, 2020 3:06 pm
Forum: Empirical & Molecular Formulas
Topic: Discussion problem help
Replies: 4
Views: 53

### Re: Discussion problem help

You can find the grams of C and N using the same method of dimensional analysis for H by converting the CO2, H2O, and N2 to mols, then multiplying them by the number of the element within the compound. You can then find the grams of O by adding together the mols of O within CO2 and H2O combined.
Wed Oct 14, 2020 2:16 pm
Forum: Administrative Questions and Class Announcements
Replies: 10
Views: 483

I have not noticed it affecting my score in any way, it usually provides tips on where to start with a question
Wed Oct 14, 2020 2:02 pm
Forum: Photoelectric Effect
Topic: 10/14 Lecture Threshold Energy
Replies: 8
Views: 97

### Re: 10/14 Lecture Threshold Energy

The threshold energy is not constant, so you would either solve for it or it would be given within the question
Wed Oct 14, 2020 1:43 pm
Forum: Student Social/Study Group
Topic: Clarification on buying an external webcam
Replies: 5
Views: 84

### Re: Clarification on buying an external webcam

How would the webcam proctoring work if we are going to be using a lockdown application during tests?