Search found 109 matches
- Mon Mar 15, 2021 5:19 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q Calculations
- Replies: 21
- Views: 1155
Re: Q Calculations
Since units ALWAYS have to match with the other units given in the equation/ formula, you would have to convert.
- Mon Mar 15, 2021 5:18 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Clarification on Heat Capacity
- Replies: 4
- Views: 459
Re: Clarification on Heat Capacity
Cp in the specific heat capacity formula stands for constant pressure, since the delta T in that formula is what stands for a change in temperature.
- Mon Mar 15, 2021 5:14 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Value of N
- Replies: 24
- Views: 1273
Re: Value of N
N is determined by the number of electrons being transferred, which can be calculated by canceling out the number of electrons in a reaction so that the total charge in reactants equals the total charge of the products.
- Mon Mar 15, 2021 5:10 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 12
- Views: 961
Re: Salt Bridges
A salt bridge basically facilitates the transfer of electrons from the anode to the cathode so that neither side has any charge build-up. It ultimately keeps the solution neutral within the galvanic cell.
- Mon Mar 15, 2021 5:07 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode and Cathode
- Replies: 25
- Views: 1461
Re: Anode and Cathode
That's right, since the loss of electrons occurs through oxidation, the process is carried out in an anode, while the gaining of electrons occurs through reduction, which is carried out in a cathode.
- Sun Mar 14, 2021 9:43 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Arrhenius Eq
- Replies: 12
- Views: 816
Re: Arrhenius Eq
This equation is on the constants and equations sheet that we could use for tests, but we didn't really cover it in lecture.
- Sun Mar 14, 2021 9:41 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Effect of Temp. on K constant
- Replies: 8
- Views: 604
Re: Effect of Temp. on K constant
Yes, it would be the opposite for an exothermic reaction, as when the temperature increases, the reaction favors the products and shifts to the right, resulting in an increase in K.
- Sun Mar 14, 2021 9:38 pm
- Forum: *Enzyme Kinetics
- Topic: catalyst
- Replies: 23
- Views: 2830
Re: catalyst
SamayaJoshi1A wrote:How do catalysts affect activation energy?
Catalysts lower activation energy so the reaction occurs at a faster rate.
- Sun Mar 14, 2021 9:36 pm
- Forum: General Rate Laws
- Topic: Youtube Review
- Replies: 17
- Views: 1054
Re: Youtube Review
Chad's Chemistry videos are so helpful when trying to get a different perspective while learning basic concepts!
- Sun Mar 14, 2021 9:34 pm
- Forum: Second Order Reactions
- Topic: Determining slow step
- Replies: 22
- Views: 1277
Re: Determining slow step
It is only when they are in the overall rate law that the reactants are involved in the slow step.
- Sun Mar 07, 2021 10:51 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gas Constant R
- Replies: 43
- Views: 4321
Re: Gas Constant R
It ultimately depends on the units. 8.314 tends to be used for energy problems which deal with joules, while 0.08206 is used for problems with volume, moles, pressure, or temperature.
- Sun Mar 07, 2021 10:48 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K value
- Replies: 20
- Views: 895
Re: K value
Although the magnitude tends to be different, since it's dependent on the reaction, K is positive because it's the rate.
- Sun Mar 07, 2021 10:44 pm
- Forum: Zero Order Reactions
- Topic: Overall order of the reaction
- Replies: 45
- Views: 2334
Re: Overall order of the reaction
If you take the sum of the orders of all the elementary reactions you can calculate the overall order.
- Sun Mar 07, 2021 10:43 pm
- Forum: *Electrophiles
- Topic: Is F a electrophile or nucleophile?
- Replies: 16
- Views: 3024
Re: Is F a electrophile or nucleophile?
F is an electrophile while F- is a nucleophile. F needs an electron while F- has an extra one.
- Sun Mar 07, 2021 10:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL EXAM QUESTIONS
- Replies: 40
- Views: 3129
Re: FINAL EXAM QUESTIONS
Definitely not all, but I'm sure it'll be a good percentage of them.
- Sun Feb 28, 2021 8:26 pm
- Forum: General Rate Laws
- Topic: Factors Affecting k
- Replies: 83
- Views: 7118
Re: Factors Affecting k
A change in temperature is a factor that would affect k
- Sun Feb 28, 2021 8:25 pm
- Forum: First Order Reactions
- Topic: rate constants
- Replies: 30
- Views: 1570
Re: rate constants
Rate constants tend to always be positive since they are dependent on concentration, and concentration is always a positive value.
- Sun Feb 28, 2021 8:23 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: K meaning
- Replies: 29
- Views: 2363
Re: K meaning
Also, we do not have to memorize this constant, as it is on the constants/equations sheet Dr. Lavelle made for us
- Sun Feb 28, 2021 8:21 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Naming Organic Molecules
- Replies: 20
- Views: 4227
Re: Naming Organic Molecules
Shark wrote:which youtube channels would you recommend?
Khan Academy and The Organic Chemistry Tutor on YouTube have been really helpful for me!
- Sun Feb 28, 2021 8:19 pm
- Forum: *Free Energy of Activation vs Activation Energy
- Topic: Temperature vs. activation energy
- Replies: 33
- Views: 2699
Re: Temperature vs. activation energy
As T increases, so too does K. As a result, increased T leads to more activation energy as a result of more collisions.
- Sun Feb 21, 2021 10:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Solids and Liquids?
- Replies: 26
- Views: 1649
Re: Solids and Liquids?
That's right, Le Chatelier's Principle only applies to gases.
- Sun Feb 21, 2021 10:31 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: percent protonation/deprotonation
- Replies: 15
- Views: 933
Re: percent protonation/deprotonation
Percent deprotonation is used for acids [H+] and percent protonation is used for bases [OH-]
- Sun Feb 21, 2021 10:30 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Strong Acids/Bases
- Replies: 19
- Views: 1485
Re: Strong Acids/Bases
Here's a link with the string acids and bases which should be memorized:
https://www.trentu.ca/online-legacy/mod ... _Bases.pdf
https://www.trentu.ca/online-legacy/mod ... _Bases.pdf
- Sun Feb 21, 2021 10:27 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy related to Enthalpy
- Replies: 20
- Views: 1061
Re: Entropy related to Enthalpy
That would be Gibbs free energy equation in which (change in Gibbs free energy) is equal to (change in enthalpy) minus (temperature in Kelvins times change in entropy).
- Sun Feb 21, 2021 10:24 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: delS at Equilibrium
- Replies: 5
- Views: 443
Re: delS at Equilibrium
It would not be at equilibrium when changing phase, only once the process is complete.
- Sun Feb 14, 2021 6:52 pm
- Forum: Ideal Gases
- Topic: Chem BL
- Replies: 107
- Views: 10872
Re: Chem BL
You could also consider taking chem BL in summer if you don't want to take it with 14 C in spring.
- Sun Feb 14, 2021 6:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs Entropy
- Replies: 39
- Views: 3370
Re: Enthalpy vs Entropy
A difference between the two is that enthalpy tends to be negative, as there is a change in heat, while entropy tends to be positive, as there is a change in disorder.
- Sun Feb 14, 2021 6:39 pm
- Forum: Phase Changes & Related Calculations
- Topic: Define Phase Change
- Replies: 78
- Views: 5932
Re: Define Phase Change
a phase change is any change between the states of matter. This includes solid to liquid, liquid to gas, solid to gas, or vice versa.
- Sun Feb 14, 2021 6:36 pm
- Forum: Phase Changes & Related Calculations
- Topic: Vapor vs gas
- Replies: 121
- Views: 15477
Re: Vapor vs gas
vapor and gas are pretty much the same thing
- Sun Feb 14, 2021 6:34 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs heat
- Replies: 31
- Views: 2726
Re: Enthalpy vs heat
Enthalpy is a state property that measures heat, whereas heat is the flow of energy
- Fri Feb 05, 2021 6:18 pm
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 157766
Re: Reading the textbook
vuongnaomi1L wrote:I actuallly dont read the textbook and whenever I have a question I either ask the UA's or go to the professor's office hours.
Same here, I feel like watching videos as well about the same concepts gives me a better understanding that just reading about it from the textbook.
- Fri Feb 05, 2021 6:16 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 472784
Re: Rusty on High School Chem [ENDORSED]
I took AP chemistry back when I was a sophomore in high school and am now taking 14A as a freshman in college so I understand how frustrating it is to forget the majority of the chemistry once learned. One tip I would have is to finish all the modules Dr. Lavelle posted on his website and also bree...
- Fri Feb 05, 2021 6:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling Reset?
- Replies: 17
- Views: 1590
Re: Sapling Reset?
There is no reset button, but you could try taking a screenshot of the question before solving it so that when you wanna go back and solve it again, you can find the question without it having been answered.
- Fri Feb 05, 2021 6:09 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Accessing the E-textbook [ENDORSED]
- Replies: 125
- Views: 35835
Re: Accessing the E-textbook [ENDORSED]
For anyone who ordered their textbook from the UCLA store and already received it, was it a physical copy? and if so, did it include an access code for sapling and/or the e-book? It's just a pdf which can be accessed and downloaded from sappling. the access code was mailed to me but some people rec...
- Wed Jan 27, 2021 9:32 pm
- Forum: Phase Changes & Related Calculations
- Topic: calculator/ calcutation error
- Replies: 5
- Views: 388
Re: calculator/ calcutation error
Alara Aygen 3K wrote:I sometimes have the same problem. Putting the numbers that have powers in parentheses solves the problem.
I agree, you should make sure you add those paranthesis especially on exams because the slightest miscalculation can cost you the entire question
- Wed Jan 27, 2021 9:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: midterm respondus
- Replies: 19
- Views: 893
Re: midterm respondus
that's right! all you need to do it download it through the link on ccle and it will automatically launch on your device
- Wed Jan 27, 2021 9:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Examples of sublimation
- Replies: 12
- Views: 574
Re: Examples of sublimation
snow and ice also undergo sublimation under certain conditions
- Wed Jan 27, 2021 9:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: midterm 1
- Replies: 11
- Views: 755
Re: midterm 1
It should be up to week three, which is about thermochemistry!
- Wed Jan 27, 2021 9:25 pm
- Forum: Phase Changes & Related Calculations
- Topic: Midterm Scratch Paper? [ENDORSED]
- Replies: 5
- Views: 354
Re: Midterm Scratch Paper? [ENDORSED]
Scratch paper is definitely allowed for this quarter as well!
- Wed Jan 20, 2021 9:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 177774
Re: How to find my posts
Massimo_Capozza_1G wrote:Does anyone else have a problem when logging into Chemistry Community where you have to re-register each time you sign-in?
That should not be the case, perhaps you should try saving your username and password on your device so that you can automatically be logged in when you open the site.
- Wed Jan 20, 2021 9:11 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: When would K be unchanged?
- Replies: 31
- Views: 1346
Re: When would K be unchanged?
The K equilibrium constant can only change through a change in temperature, a change in concentration will not change the value of K.
- Wed Jan 20, 2021 9:09 pm
- Forum: Ideal Gases
- Topic: Equilibrium Constant (Q and K)
- Replies: 13
- Views: 689
Re: Equilibrium Constant (Q and K)
Although they are not the same, they are related. If you have not waited long enough for the reaction to reach equilibrium, you can't use K and, thus, must use Q to determine the reaction quotient.
- Wed Jan 20, 2021 9:07 pm
- Forum: Ideal Gases
- Topic: PV=nRT and Equilibrium
- Replies: 12
- Views: 637
Re: PV=nRT and Equilibrium
I mostly use PV=nRT in equilibrium to convert gases to concentration and vice versa, depending on the information given in the question. The equation is also helpful for Le Chatelier's Principle because you can see how pressure and volume are related to see volume changes would affect the reaction....
- Wed Jan 20, 2021 9:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic v. Exothermic
- Replies: 139
- Views: 18428
Re: Endothermic v. Exothermic
That's right, since exothermic reactions will be losing heat, that means that the delta h must be negative.
- Sat Jan 16, 2021 9:18 pm
- Forum: Student Social/Study Group
- Topic: Course Evals
- Replies: 18
- Views: 1040
Re: Course Evals
These are only optional and recommended to fill out, but it won't hurt you if you don't do them!
- Sat Jan 16, 2021 9:16 pm
- Forum: Student Social/Study Group
- Topic: Midterms?
- Replies: 14
- Views: 848
Re: Midterms?
Madison Wong 3H wrote:the first midterm is january 29 during your lecture time, but it's still 50 minutes. Before it was discussions, but now everyone takes it on the same day during their lecture time.
I didn't know that, thanks for the info! :)
- Sat Jan 16, 2021 9:13 pm
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3493
Re: New Joke Chain
Did you hear oxygen went on a date with potassium?
It went OK.
It went OK.
- Sat Jan 16, 2021 9:10 pm
- Forum: Student Social/Study Group
- Topic: Advice for study
- Replies: 31
- Views: 1652
Re: Advice for study
I like to play jazz music while im studying in order to get rid of any distractions in the house.
- Sat Jan 16, 2021 9:04 pm
- Forum: Student Social/Study Group
- Topic: Chemistry Community Posts
- Replies: 22
- Views: 1132
Re: Chemistry Community Posts
Say if I made up the 5 posts that were due last Sunday for week one.. would I get full credit or be docked down for being late? My ta last quarter said I would not be able to get the points for that week since I had done them the week after they were due, but I ended up getting full points so maybe...
- Sun Jan 10, 2021 12:32 am
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL EXAM QUESTIONS
- Replies: 40
- Views: 3129
Re: FINAL EXAM QUESTIONS
I wouldn't be surprised if not too many questions from homework are on the final, so I suggest focusing more on the type of problems as opposed to specific ones from the textbook.
- Sun Jan 10, 2021 12:29 am
- Forum: Administrative Questions and Class Announcements
- Topic: other resources
- Replies: 5
- Views: 876
Re: other resources
I also agree! Organic Chemistry Tutor on YouTube as helped me solidify whatever Dr. Lavelle taught us in his lectures.
- Sun Jan 10, 2021 12:28 am
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry Community posts after this quarter [ENDORSED]
- Replies: 7
- Views: 1105
Re: Chemistry Community posts after this quarter [ENDORSED]
Since you could see posts dating back from last year, I believe they should remain on the site as long as it is still functioning.
- Sun Jan 10, 2021 12:27 am
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling Assignments
- Replies: 30
- Views: 2185
Re: Sapling Assignments
Those are just one of the extra resources Dr. Lavelle has given us as practice for the midterms/final.
- Tue Dec 15, 2020 6:09 pm
- Forum: Student Social/Study Group
- Topic: Plans for Relaxing After Finals
- Replies: 98
- Views: 21939
Re: Plans for Relaxing After Finals
we can't really go out, so I plan to spend as much time with my family as possible!
- Tue Dec 15, 2020 6:00 pm
- Forum: Student Social/Study Group
- Topic: How are you?
- Replies: 154
- Views: 18122
Re: How are you?
Just finished my last final, FINALLY I can enjoy break!
- Tue Dec 15, 2020 5:58 pm
- Forum: Student Social/Study Group
- Topic: Grades
- Replies: 29
- Views: 1560
Re: Grades
grades should be out by Saturday hopefully!
- Tue Dec 15, 2020 5:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs Angular
- Replies: 20
- Views: 1021
Re: Bent vs Angular
Both bent and angular are the same, so you'd choose whichever one is given in the answer choices if it was a multiple choice format.
- Tue Dec 15, 2020 5:52 pm
- Forum: Properties of Light
- Topic: Wavelength
- Replies: 26
- Views: 1391
Re: Wavelength
wavelength should always be m unless the question is asking for a different unit.
- Tue Dec 15, 2020 5:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 643645
Re: Saying Thank You to Dr. Lavelle
Thank you Dr. Lavelle! Looking forward to chem 14B!
- Tue Dec 15, 2020 5:36 pm
- Forum: Student Social/Study Group
- Topic: Study music
- Replies: 59
- Views: 7476
Re: Study music
I like to listen to jazz music while I study, as it calms me down when I start freaking out over not understanding a certain concept.
- Tue Dec 15, 2020 5:35 pm
- Forum: Balancing Chemical Reactions
- Topic: Diatomic Molecules
- Replies: 7
- Views: 937
Re: Diatomic Molecules
https://www.google.com/url?sa=i&url=https%3A%2F%2Fmccord.cm.utexas.edu%2Fchembook%2Fpage-nonav.php%3Fchnum%3D1%26sect%3D12&psig=AOvVaw1aUqGpVI60plDDL7M-zqye&ust=1608168782649000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCKirzNyt0e0CFQAAAAAdAAAAABAD Here is a link to a good illust...
- Tue Dec 15, 2020 5:06 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: chelating ligands [ENDORSED]
- Replies: 51
- Views: 101193
Re: chelating ligands [ENDORSED]
Jessica Hu 3L wrote:Then to clarify, a ring is what is a chelate? and that forms when it's a ligand-spare atom-spare atom-same ligand?
I am also confused on this. Could someone clarify?
- Thu Dec 10, 2020 2:34 pm
- Forum: Biological Examples
- Topic: chelates
- Replies: 8
- Views: 605
Re: chelates
According to what Dr. Lavelle had mentioned in his previous lecture, a chelate is a complex containing a ligand that forms a ring of atoms, which include central metal atoms. Chelating ligands often bind cations tightly, because they are forming more than one bond.
- Thu Dec 10, 2020 2:30 pm
- Forum: Naming
- Topic: Naming quizlet
- Replies: 41
- Views: 2063
Re: Naming quizlet
Thank you so much for this! It'll be very helpful for when I study!
- Thu Dec 10, 2020 2:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 470
Re: Bond Angles
A slightly smaller or larger bond angle, in this case 109.5 degrees, could be the result of lone paired electrons which take up more space than the usual bonds.
- Thu Dec 10, 2020 2:17 pm
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 435440
Re: Final Jitters
Since the final is cumulative, it might help to review any previous lecture notes from this quarter or watch the lectures themselves.
- Thu Dec 10, 2020 2:14 pm
- Forum: Amphoteric Compounds
- Topic: How to know if a molecule is amphoteric
- Replies: 9
- Views: 2183
Re: How to know if a molecule is amphoteric
How can we identify if a molecule is amphoteric or not? Other than water being a common one? Dr. Lavelle had characterized amphoteric compounds as having both basic and acidic character, so in the presence of a base, this molecule would act as an acid, and in the presence of an acid, it would act a...
- Fri Dec 04, 2020 10:18 pm
- Forum: Coordinate Covalent Bonds
- Topic: Hydrogen bonding
- Replies: 15
- Views: 959
Re: Hydrogen bonding
Since hydrogen bonding occurs through an intramolecular force, it would be considered a type of dipole-dipole interaction as opposed to a coordinate covalent bond.
- Fri Dec 04, 2020 10:14 pm
- Forum: Lewis Structures
- Topic: Most Stable Structure
- Replies: 23
- Views: 3694
Re: Most Stable Structure
MichaelMendozaD1F wrote:is most "stable" the same as most likely or favorable? I believe they are synonymous in these types of problems but I just want to make sure.
yes, more stable lewis structures also tend to be those with the lower formal charge, so they are more favorable .
- Fri Dec 04, 2020 10:11 pm
- Forum: Sigma & Pi Bonds
- Topic: pi bonds
- Replies: 16
- Views: 1253
Re: pi bonds
Think of pi bonds as a vertical overlapping of bonds, so they cannot rotate, while sigma bonds consist of horizontal overlapping, in which they can rotate.
- Fri Dec 04, 2020 10:09 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 24
- Views: 1334
Re: Sigma and Pi Bonds
I think that, in general, since both single and double bonds have a a sigma, but only double bonds have a pi, they could be referred to has simply pi bonds.
- Fri Dec 04, 2020 10:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 14B Enrollment [ENDORSED]
- Replies: 67
- Views: 19147
Re: 14B Enrollment [ENDORSED]
I'm pretty sure that since Dr. Lavelle is increasing his sections, there should be a lot more openings, which means that waitlisted students should be able to get in without a problem.
- Tue Nov 24, 2020 7:20 pm
- Forum: General Science Questions
- Topic: # of chem posts
- Replies: 27
- Views: 2023
Re: # of chem posts
Alison Perkins 2C wrote:jasmineculilap_2J wrote:You need 5 posts per week, so 35 posts are needed.
Do general questions and jokes count? Or strictly chemistry material?
Pretty sure that everything/anything posted counts!
- Mon Nov 23, 2020 11:45 pm
- Forum: *Shrodinger Equation
- Topic: SE importance
- Replies: 4
- Views: 480
Re: SE importance
This equation basically refers to electron density and the likelihood of finding an electron within it.
- Mon Nov 23, 2020 11:42 pm
- Forum: Empirical & Molecular Formulas
- Topic: Finding Mass % Composition
- Replies: 4
- Views: 395
Re: Finding Mass % Composition
SamayaJoshi1A wrote:Hi! I don't think this is a necessary step for any of the questions. Dr. Lavelle just does this to show that there is a ratio and that the percentages should add up to 100 percent.
I agree, Dr. Lavelle just tries to show us the w=actual process, but it is not necessary.
- Mon Nov 23, 2020 11:40 pm
- Forum: Balancing Chemical Reactions
- Topic: States of matter in chem equations
- Replies: 13
- Views: 1078
Re: States of matter in chem equations
Although they should not have much of an effect on your answer, I would put it just in case :)
- Mon Nov 23, 2020 11:39 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3942441
Re: Post All Chemistry Jokes Here
Q: What is the chemical formula for "coffee"?
A: CoFe2
Q: What is the chemical formula for "banana"?
A: BaNa2
A: CoFe2
Q: What is the chemical formula for "banana"?
A: BaNa2
- Mon Nov 23, 2020 11:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 177774
Re: How to find my posts
All you have to do is go to "Quick Links" and then "Your Posts" !
- Mon Nov 23, 2020 11:36 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass and Molecular Mass Difference?
- Replies: 24
- Views: 4882
Re: Molar Mass and Molecular Mass Difference?
Those two are pretty interchangeable, they just require different units I think.
- Sun Nov 15, 2020 11:54 am
- Forum: Trends in The Periodic Table
- Topic: Atomic radius
- Replies: 4
- Views: 293
Re: Atomic radius
Hi! I agree with the post above, and if I recall correctly, the horizontal trend is a bit stronger than the vertical. However, I'm unsure if there are any straight up exceptions to the atomic radius trend. I think Dr. Lavelle might have mentioned these exceptions in his pervious lectures where he d...
- Sun Nov 15, 2020 11:49 am
- Forum: Student Social/Study Group
- Topic: Online textbook answer key
- Replies: 6
- Views: 633
Re: Online textbook answer key
Maybe you could try downloading the the answer key and then opening it from there? That's what I did so now the answer key is saved on my computer and I can access it anytime I want.
- Sun Nov 15, 2020 11:46 am
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 435440
Re: Final Jitters
I always eat a good, healthy, meal the day before my test and something light light a nutrition bar the morning of. That usually keeps me energized helps me think better when taking the test.
- Sun Nov 15, 2020 11:44 am
- Forum: Administrative Questions and Class Announcements
- Topic: How to list Chem_Mod posts
- Replies: 25
- Views: 94406
Re: How to list Chem_Mod posts
This is so helpful, thank you!! Also, I think Chem_mod might be Dr. Lavelle only, not too sure though.
- Sun Nov 15, 2020 11:40 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3942441
Re: Post All Chemistry Jokes Here
I see that everyone is making bad chemistry jokes because all the good ones Argon.
Q: What did the scientist say when he found 2 isotopes of helium?
A: HeHe
Q: What did the scientist say when he found 2 isotopes of helium?
A: HeHe
- Sun Nov 08, 2020 4:18 pm
- Forum: Trends in The Periodic Table
- Topic: # of electrons
- Replies: 23
- Views: 754
Re: # of electrons
We can count the number of elements within an atom based on its atomic number, which is also the number of protons in that element. In an ion, it would be the atomic number plus the charge (negative or positive).
- Sun Nov 08, 2020 4:14 pm
- Forum: Electronegativity
- Topic: Electronegativity trend
- Replies: 18
- Views: 797
Re: Electronegativity trend
Electronegativity trend is ultimately very similar to the ionization energy trend, as it increases in the periodic table from left to right and decreases down the periodic table.
- Sun Nov 08, 2020 4:08 pm
- Forum: Lewis Structures
- Topic: Lone Pairs Question
- Replies: 22
- Views: 1890
Re: Lone Pairs Question
In regards to a Lewis structure, a long pair consists of valence electrons of one atoms which are neither bonded nor shared with any other atom.
- Sun Nov 08, 2020 4:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: Extra Valence Electrons
- Replies: 10
- Views: 513
Re: Extra Valence Electrons
As Dr. Lavelle had mentioned in one of his previous lectures, these elements would be exceptions to the octet rule, which is why they could hold that extra electron.
- Sun Nov 08, 2020 4:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 177774
Re: How to find my posts
All you have to do is click on "Quick links" on the top left, then go to "your posts." You can filter it so that you check what posts you made within a select time frame.
- Fri Oct 30, 2020 5:59 pm
- Forum: Properties of Electrons
- Topic: What does this symbol mean?
- Replies: 18
- Views: 2613
Re: What does this symbol mean?
That symbol stands for "proportional to" and is used to describe how one thing is the same as or equal to another thing. Similarly, it can be used to describe something as "inversely proportional" to another thing when that second term has a "^-1" on it.
- Fri Oct 30, 2020 5:53 pm
- Forum: Properties of Light
- Topic: Wavelength
- Replies: 26
- Views: 1391
Re: Wavelength
When solving a problem, wavelength must always be written in terms of m, since the other variables in the equation would be in m. However, when writing the wavelength as the final answer, it should be converted to nm in order to determine the spectrum.
- Fri Oct 30, 2020 5:49 pm
- Forum: Properties of Light
- Topic: rydberg's constant
- Replies: 11
- Views: 1038
Re: rydberg's constant
The the several practice problems we have done for this class so far, the value for the Rydberg constant was 3.289x10^15, so that should be the only value you use when solving the problems as far as Chem14A goes.
- Fri Oct 30, 2020 5:45 pm
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 6624
Re: Is c always the speed of light?
Yes! At least so far in Chem14A c is always a constant which represents the speed of light, so it should not change.
- Fri Oct 30, 2020 5:42 pm
- Forum: Properties of Light
- Topic: Midterm
- Replies: 42
- Views: 1860
Re: Midterm
The midterm was about 12 problems, with 50 minutes given for us to complete it. We could use the constants and equations handout as well as the periodic table handout as long as we printed it out and did not write anything on it.
- Thu Oct 22, 2020 10:23 pm
- Forum: Properties of Light
- Topic: Electrons Emitted
- Replies: 7
- Views: 338
Re: Electrons Emitted
Since kinetic energy would be 0 in this scenario, you would just have to divide the total energy by the work function, taking into account whatever is already given to you or whatever you have previously solved in the problem.
- Thu Oct 22, 2020 10:17 pm
- Forum: Properties of Light
- Topic: Units for wavelength/frequency
- Replies: 18
- Views: 1446
Re: Units for wavelength/frequency
The units for wavelength is in meters, and the units for frequency is in Hz, or s^-1. Since the midterm is multiple choice, the only thing you should worry about in terms of units is being able to convert if it is given in any other unit, such as nanometers instead of meters.
- Thu Oct 22, 2020 10:14 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: What does mmol stand for? [ENDORSED]
- Replies: 43
- Views: 6442
Re: What does mmol stand for? [ENDORSED]
Just like in mg, the m stand for milligrams, the m in mol stands for milligrams. It is simply the prefix "milli."
- Thu Oct 22, 2020 10:09 pm
- Forum: Balancing Chemical Reactions
- Topic: Writing Equations [ENDORSED]
- Replies: 15
- Views: 1297
Re: Writing Equations [ENDORSED]
So when asking us to write an equation with an element that happens to be diatomic, like oxygen, would we always but a subscript of 2 with it? Because I feel like I have seen instances where there wasn't any subscripts with it.
- Wed Oct 21, 2020 9:41 pm
- Forum: Photoelectric Effect
- Topic: How to calculate the kinetic energy, energy and frequency? [ENDORSED]
- Replies: 25
- Views: 7625
Re: How to calculate the kinetic energy, energy and frequency? [ENDORSED]
AustinMcBrideDisc3C wrote:diegomartinez1F wrote:Mass of electron is given:
Me= 9.10938 x 10^-31 kg
Do we need to convert this to grams or can we keep it as kg?
We need to keep it in kg, as all of the other units include kg, such as Joules (kg.m^2/s^2)
- Thu Oct 15, 2020 2:38 am
- Forum: Balancing Chemical Reactions
- Topic: Whole Number Stoichiometric Coefficients
- Replies: 12
- Views: 1698
Re: Whole Number Stoichiometric Coefficients
It is much easier to work with whole number in balanced stoichiometric equations, so that is recommended, although fractions in a balanced equation would not technically be wrong, just harder to work out. Dr. Lavelle also mentioned it would be better to use whole numbers when balancing stoichiometri...