## Search found 61 matches

Sun Jan 17, 2021 10:38 pm
Forum: Student Social/Study Group
Topic: Logistics for the Midterm
Replies: 10
Views: 37

### Logistics for the Midterm

Hi I was wondering if the midterm will be held similarly to how exams were held in Chem 14A. In the syllabus it says we are taking them during our lecture times, so will there be zoom proctoring by our TA's still? I'm sorry if this has been addressed already! Thank you!
Sun Jan 17, 2021 10:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: cancelling out variables in K eq
Replies: 4
Views: 12

### Re: cancelling out variables in K eq

Remember in this problem as well the mole ratios aren't all 1 so there should be an x^2!
Sun Jan 17, 2021 10:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Making the Assumption that Change x is Small
Replies: 4
Views: 10

### Re: Making the Assumption that Change x is Small

10^-3! But in Dr. Lavelle's Friday lecture, he talks about this is more detail concerning the flexibility of that value and how we can double check when it comes to % ionization!
Sun Jan 17, 2021 10:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Total pressure calculation
Replies: 8
Views: 25

### Re: Total pressure calculation

Adding all partial pressures gives way for total pressure in a system!
Sun Jan 17, 2021 10:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: When would K be unchanged?
Replies: 31
Views: 64

### Re: When would K be unchanged?

K would change when the temperature changes. I believe the 6/7 sapling problems tackle this.
Sun Jan 10, 2021 2:02 pm
Forum: Student Social/Study Group
Topic: New Year Resolutions?
Replies: 52
Views: 168

### Re: New Year Resolutions?

I want to exercise more! I've been very sedentary recently so I want to go outside and run more for instance.
Sun Jan 10, 2021 2:01 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 257

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

Remember that this course is very individualistic so keep up with the assigned problems, lectures, and study sessions because it's really easy to fall behind.
Sun Jan 10, 2021 1:57 pm
Forum: Ideal Gases
Topic: inert gas and pressure changes
Replies: 9
Views: 33

### Re: inert gas and pressure changes

It doesn't change the volume which means it doesn't change the concentration.
Sun Jan 10, 2021 12:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: I in ICE Chart
Replies: 11
Views: 35

### Re: I in ICE Chart

Yes! For example in a decomposition reaction this would be the case!
Sun Jan 10, 2021 12:36 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing volume
Replies: 6
Views: 27

### Re: Changing volume

The "quickway" is just showing that you determine the way it shifts when the pressure changes the volume by looking at the number of moles. For example, if you double the pressure (halve the volume) it would go to the side with fewer moles.
Mon Dec 14, 2020 10:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 337
Views: 139616

### Re: Saying Thank You to Dr. Lavelle

Hi Dr. Lavelle,
Thank you for being a great professor for my first quarter at UCLA! I can't wait for more next quarter!
Fri Dec 11, 2020 12:12 am
Forum: Amphoteric Compounds
Topic: Amphoteric
Replies: 8
Views: 90

### Re: Amphoteric

I'm pretty sure amphoteric compounds react depending on the molecules around them and since water is relatively neutral it would be hard to tell. I don't think it will be asked!
Fri Dec 11, 2020 12:11 am
Forum: Bronsted Acids & Bases
Topic: HClO3 Strong Acid
Replies: 4
Views: 61

### Re: HClO3 Strong Acid

It really depends. When I was in AP chem, my teacher told us to only think of a few acids as strong acids and all others as weak, but I don't know if that's entirely accurate!
Fri Dec 11, 2020 12:08 am
Forum: Photoelectric Effect
Topic: Wednesday Review
Replies: 1
Views: 23

### Re: Wednesday Review

If you didn't know b was inherently incorrect you can use the process of elimination! For a, when you have higher intensity let's say a brighter light, it doesn't affect the frequency of the resulting kinetic energy. For C, it is saying that kinetic energy and frequency are proportional which they a...
Mon Dec 07, 2020 12:43 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8521
Views: 1472238

### Re: Post All Chemistry Jokes Here

what is an iron-deficient female?
just a male
Sun Dec 06, 2020 12:02 am
Forum: Student Social/Study Group
Topic: Point distribution
Replies: 11
Views: 103

### Re: Point distribution

I feel the same way! But it puts him in a hard position because it seems like many are doing well which would make a curve very small to nonexistent :(
Sun Dec 06, 2020 12:00 am
Forum: Student Social/Study Group
Topic: How are you?
Replies: 111
Views: 758

### Re: How are you?

i'm catching up on lectures! so basically tired lol
Sat Dec 05, 2020 11:58 pm
Forum: Naming
Topic: en
Replies: 8
Views: 76

### Re: en

Specific to week 9's homework, it's a bidentate ligand which would mean the coordination number would be different!
Sat Dec 05, 2020 11:57 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.1 Difference in pH
Replies: 1
Views: 20

### Re: 6B.1 Difference in pH

I assume because you are assuming the HCL molar concentration was at 100% which would dissociate and give you 100% dissociation of hydronium ions needed to find pH . After dilution, this would be 12% of that value which means that you can take that 100% of dissociation and convert it to a 12 percent...
Mon Nov 30, 2020 12:01 am
Forum: Student Social/Study Group
Replies: 29
Views: 309

### Re: Grading Scale for Chem14A

I believe that 90% should be the cutoff for receiving an A of any kind. But in some classes I took in the past they curved the final grades so that there could be a specific percentage of students with an A and a B and so forth. But I'm not sure how he's going to go about that. I also agree that 90...
Mon Nov 30, 2020 12:00 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8521
Views: 1472238

### Re: Post All Chemistry Jokes Here

Do you like chemistry?
Na
Wed Nov 25, 2020 8:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Shape NonPolar
Replies: 2
Views: 28

### Re: Bent Shape NonPolar

The bent shape can mean different things! If you look up a chart of all the molecular geometries bent can be used for different electron domain geometries. However, in all of those instances, the molecule would be polar to my knowledge because of the lone pairs. The lone pairs make it so that there ...
Wed Nov 25, 2020 8:37 pm
Forum: Student Social/Study Group
Topic: Finals!
Replies: 43
Views: 348

### Re: Finals!

Thank you all for all the responses! I'll definitely study everything then!
Sat Nov 21, 2020 6:41 pm
Forum: Hybridization
Topic: Double bonds structures
Replies: 5
Views: 69

### Re: Double bonds structures

Hi! I had a question about something Dr. Lavelle mentioned in lecture, that if an atom has a double bond, then it cannot move around and it is locked into a position by these bonds. I was wondering how this applies to structures with resonance and if the electrons are delocalized? Thanks! Hi! A dou...
Sat Nov 21, 2020 6:39 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: Strongest/weakest intermolecular forces
Replies: 6
Views: 85

### Re: Strongest/weakest intermolecular forces

Anna Martin 2l wrote:Could covalent bonds be a part of this list?

Covalent bonds are intrAmolecular forces! That exist within the molecule!
Sat Nov 21, 2020 6:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: double bonding
Replies: 8
Views: 74

### Re: double bonding

Like said above, the molecular geometry really depends on the electron domain geometry which includes lone pairs and bonds. If you look up a chart with the different electron domain geometries with their molecular geometry I think it will make more sense! Hope this helps!
Sat Nov 21, 2020 6:34 pm
Forum: Student Social/Study Group
Replies: 29
Views: 309

### Re: Grading Scale for Chem14A

I'm not exactly sure, I mostly try to estimate my grade based on the points I'm receiving (like getting points for chemistry community, the hw, etc). And then based on how my midterms go, I try to see what range I'm in (like whether I'm passing or not lol). I don't think Lavelle has specifically sa...
Sat Nov 21, 2020 6:33 pm
Forum: Student Social/Study Group
Topic: Finals!
Replies: 43
Views: 348

### Finals!

Hi Everyone,
I'm not sure if Dr. Lavelle has addressed this already, but is the final exam cumulative, or does it only cover new material? Thanks!
Wed Nov 18, 2020 11:12 am
Forum: Student Social/Study Group
Replies: 29
Views: 309

Hi everyone,
I was wondering what the exact grade scale for this class is in terms of percentages. Like for instance is an A a 94% or 93%? Thanks!
Sat Nov 14, 2020 4:48 pm
Forum: Lewis Structures
Topic: Outline 3 Sheet Question
Replies: 3
Views: 27

### Re: Outline 3 Sheet Question

There are also different notations for double or triple bonds. See a molecule of benzene for more information. Hope this helps!
Sat Nov 14, 2020 4:45 pm
Forum: Student Social/Study Group
Topic: Drawing Lewis Structures
Replies: 4
Views: 32

### Drawing Lewis Structures

I'm confused about how we are going to draw the lewis structures if the test is online. Are we uploading pictures of our drawings? Sorry if this is has already been answered. Thank you!
Sat Nov 14, 2020 4:43 pm
Forum: Student Social/Study Group
Topic: Study Group
Replies: 4
Views: 55

### Re: Study Group

I would also like to join if there was a study group made!
Fri Nov 13, 2020 11:34 pm
Forum: Dipole Moments
Topic: H-Bonds
Replies: 14
Views: 109

### Re: H-Bonds

Only molecules with H attached to electronegative atoms, such as N, O, and F can hydrogen bond. Yes this is exactly true! Hydrogen bonds are intermolecular forces like said in this example and are the strongest INTERmolecular force. The hydrogen bonds within a water molecule for instance is not the...
Fri Nov 13, 2020 11:32 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: is it polar
Replies: 6
Views: 80

### Re: is it polar

To see if there is a dipole moment, you look at the elements electronegativity and you subtract the bonded elements electronegativities and the difference allows you to know the nature of their interaction: dipole, nonpolar, etc.
Wed Nov 04, 2020 4:44 pm
Forum: Ionic & Covalent Bonds
Topic: Textbook Problem 2A.1
Replies: 4
Views: 25

### Re: Textbook Problem 2A.1

I believe that even though d is a lower energy level it still has them as valence electrons because the shell is incomplete. I might be wrong! Hope this helps.
Wed Nov 04, 2020 4:42 pm
Forum: Ionic & Covalent Bonds
Topic: 2 paired electrons
Replies: 3
Views: 12

### Re: 2 paired electrons

Use hund's rule! This is the diagram with the arrows and boxes to denote orbitals and electron spin! Hope this helps!
Wed Nov 04, 2020 4:40 pm
Forum: Lewis Structures
Topic: Valence Electrons
Replies: 10
Views: 67

### Re: Valence Electrons

Some tricks I use for finding valence electrons are looking at the electron configuration and seeing which electrons are in the highest energy level and which have incomplete shells, checking that with the element's point on the periodic table, and finally checking that with the electron domain geom...
Sun Nov 01, 2020 11:43 pm
Forum: Photoelectric Effect
Topic: sapling #22
Replies: 2
Views: 25

### Re: sapling #22

Use the kinetic energy equation and de Broglie equation to find the velocity!
Sun Nov 01, 2020 11:41 pm
Forum: Trends in The Periodic Table
Topic: studying
Replies: 12
Views: 61

### Re: studying

When I watched the lectures I took really thorough notes and I did all the practice problems and the UA worksheets! I'm not sure how I faired yet, but that's what has worked for me.
Sun Nov 01, 2020 11:29 pm
Forum: Properties of Light
Topic: Amplitude and Intensity Relationship
Replies: 4
Views: 29

### Re: Amplitude and Intensity Relationship

There is a proportional relationship between amplitude and intensity in terms of light.
Sun Nov 01, 2020 11:23 pm
Forum: Trends in The Periodic Table
Topic: Oxygen vs Nitrogen and Fluorine
Replies: 4
Views: 38

### Re: Oxygen vs Nitrogen and Fluorine

This is a special phenomenon! It's because the half shell of the p shape is 3 and atoms like to be in full or half-shells. So it would want to get rid of one electron more!
Sun Nov 01, 2020 11:19 pm
Forum: Student Social/Study Group
Topic: Test Scored for Midterm 1
Replies: 49
Views: 382

### Re: Test Scored for Midterm 1

Are all the tests the same? Because I thought I had a mistake on my version. Let me know if anyone saw this!
Sun Nov 01, 2020 11:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Participation Points [ENDORSED]
Replies: 62
Views: 1014

### Re: Participation Points[ENDORSED]

What is the day/time in PST when participation is counted? Thank you!
Sun Nov 01, 2020 11:14 pm
Forum: Properties of Light
Topic: How to remember what v is in equations
Replies: 46
Views: 261

### Re: How to remember what v is in equations

Use the equation sheet!
Tue Oct 27, 2020 12:01 am
Forum: Student Social/Study Group
Topic: Midterm scratch paper
Replies: 9
Views: 50

### Re: Midterm scratch paper

thank you to everyone who answered my post I really appreciate the help!
Sat Oct 24, 2020 10:37 pm
Forum: Student Social/Study Group
Topic: Midterm scratch paper
Replies: 9
Views: 50

### Midterm scratch paper

Hi!
I was wondering if we will have to turn in our scratch paper for the midterm and if we have to show our work for each problem. Thanks!
Sat Oct 24, 2020 9:51 pm
Forum: Student Social/Study Group
Topic: How to relax
Replies: 113
Views: 596

### Re: How to relax

I usually watch Netflix, read a book, take a nap, hang out with my dogs, or go on a walk! Usually, time away from the screens are the most relaxing for me.
Sat Oct 24, 2020 9:50 pm
Forum: Student Social/Study Group
Topic: Constants and Equation Sheet
Replies: 3
Views: 27

### Re: Constants and Equation Sheet

Yes in his most recent email he sent two links: one to a periodic table and one to a formula sheet that need to printed by the exam. I'm not sure if they're the same on the website, but possibly! Hope this helps!
Sat Oct 24, 2020 9:48 pm
Forum: Balancing Chemical Reactions
Topic: L.39 Fundamental Question
Replies: 3
Views: 59

### Re: L.39 Fundamental Question

Yes I agree that the oxygen in the air is the same as oxygen gas. Naturally, oxygen appears in a pair just like H, N, Cl, Br, etc. Hope this helps!
Sat Oct 24, 2020 9:46 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Multi-Electron Atoms
Replies: 3
Views: 34

### Re: Multi-Electron Atoms

There are other factors that affect electrostatic potential energy including the shielding effect by the inner energy levels since the electrons repel the other electrons. They also repel those in the same energy level.
Sat Oct 24, 2020 9:43 pm
Forum: Student Social/Study Group
Topic: Midterm Question
Replies: 9
Views: 45

### Re: Midterm Question

I think Dr. Lavelle sent an email regarding this question! He attached a periodic table and a constant/equation sheet that we need to be printed before the exam. I hope this helps!
Fri Oct 16, 2020 11:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Finding the amount of molecules in compounds using mole conversions
Replies: 3
Views: 45

### Re: Finding the amount of molecules in compounds using mole conversions

Could someone explain how 1 mol = 6.022 x 10 23 atoms but can also equal 6.022 x 10 23 molecules? Also, there is a problem in the textbook that says to "Calculate the amount of urea molecules, OC(NH 2 ) 2 in 2.5 x 10 5 g of urea," but gives the answer (3.8 x 10 3 ) in moles. If 1 mol = 6....
Fri Oct 16, 2020 11:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Jumping energy levels vs. Removing an electron
Replies: 3
Views: 33

### Re: Jumping energy levels vs. Removing an electron

From the E = -hR/n^2 equation we know that the greater the n, the closer E gets to 0. How close is close enough to be considered as 0? In other words, after how many levels does an electron have to move up in order for it to be considered as no longer interacting with the atom? Also, is it differen...
Fri Oct 16, 2020 11:40 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8521
Views: 1472238

### Re: Post All Chemistry Jokes Here

what is batman's favorite element?
sodium! na na na na na na na na!
Fri Oct 16, 2020 11:37 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Conservation of energy
Replies: 4
Views: 30

### Re: Conservation of energy

For the hydrogen Bohr model, I was a bit confused about the conservation of energy. Does the electron always start at n=1 since it is a Hydrogen atom? If so, how can the electron end up at a different energy level other than n=1? For example, if the electron is excited to n=3 and drops back down to...
Fri Oct 16, 2020 11:33 pm
Forum: SI Units, Unit Conversions
Topic: Mnemonic
Replies: 6
Views: 59

### Re: Mnemonic

Shana Patel 1C wrote:Thank you so much, that was so helpful! I'm still shocked that both of you used the same one. Did you learn it in high school, or did I miss something during class?

Yes I learned it in high school!
Sat Oct 10, 2020 9:15 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E 23
Replies: 3
Views: 44

### Re: E 23

Yes. You need to multiply it by it's stoichiometric ratio to the other ion. For instance, 10 H20 molecules for every molecule of Sodium Carbonate Hydrate. Hope this helps!
Sat Oct 10, 2020 8:58 pm
Forum: SI Units, Unit Conversions
Topic: Mnemonic
Replies: 6
Views: 59

### Re: Mnemonic

I remember it as K.H.D.U.D.C.M : King Henry Doesn't Usually Drink Chocolate Milk. Or Kilo, Hecto, Deca, Unit (for example: gram), Deci, Centi, Mili. Hope this helps!
Sat Oct 10, 2020 8:56 pm
Forum: SI Units, Unit Conversions
Topic: Unit Rounding
Replies: 11
Views: 79

### Re: Unit Rounding

It really depends! I rely heavily on the significant figure rules I've learned in high school. Try to read up on significant figures in the textbook. The way I solve problems is by not rounding as much as possible as this can make your data inaccurate. Do your calculations then find the needed signi...
Sat Oct 10, 2020 8:53 pm
Forum: Properties of Light
Topic: Sun Spectrum
Replies: 3
Views: 37

### Re: Sun Spectrum

I believe that the sun emits all forms of electromagnetic radiation. If we had a different sun (a different star) I believe we may have found different amounts of each radiation, as our sun emits an unequal amount of each portion of the spectrum. Hope this helps!
Mon Oct 05, 2020 8:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 103
Views: 7154

### Re: Accessing the E-textbook[ENDORSED]

I'm not 100% sure if it's mandatory, but I have used the free trial and completed the Week 1 homework and it showed up it in the gradebook on CCLE. And I'm pretty sure on the syllabus it makes up a part of the grade percentage. Hope this helps!