Search found 100 matches
- Tue Mar 17, 2020 2:45 pm
- Forum: Student Social/Study Group
- Topic: Coronavirus Joke
- Replies: 14
- Views: 1763
Re: Coronavirus Joke
LOL this definitely helped lighten the mood
- Sat Mar 14, 2020 4:29 pm
- Forum: General Science Questions
- Topic: Who makes the Final
- Replies: 23
- Views: 1374
Re: Who makes the Final
I think that Lavelle makes the final and the midterm and the TAs make the tests.
- Sat Mar 14, 2020 4:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading Scale
- Replies: 16
- Views: 1041
Re: Grading Scale
I think he'll use a similar grading scale. The syllabus just says that the cut off for a C- is 50% and nothing in the emails has indicated that the grading scale would be changed.
- Fri Mar 13, 2020 5:02 pm
- Forum: Student Social/Study Group
- Topic: Tips for Staying Focused
- Replies: 64
- Views: 3588
Tips for Staying Focused
Hey guys, I've been finding it really hard to focus with everything that has been going on. Does anyone have tips on how to stay focused? I've been trying to study and it has been hard with all the updates for next quarter and the stress from that. Any tips would be appreciated! Thanks in advance. :)
- Thu Mar 12, 2020 7:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: W20, Week 10 Discussion 2F, 2I, 2L
- Replies: 10
- Views: 7426
Re: W20, Week 10 Discussion 2F, 2I, 2L
My TA just had us email our week 10 homework to her. :) You can probably do the same.
- Wed Mar 11, 2020 2:19 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 5
- Views: 399
Re: Final
Most likely we'll have to turn in the final online. :)
- Sun Mar 08, 2020 10:53 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Study Advice
- Replies: 73
- Views: 6811
Re: Study Advice
I like going through the homework problems to practice doing problems and going through the worksheets from discussion. I like to attend the review sessions that go over the topics I am not understanding or have questions about. Drop-in sessions or office hours would be a good resource if you had sp...
- Sun Mar 08, 2020 10:17 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell Diagram
- Replies: 21
- Views: 1141
Re: Cell Diagram
I think it would be okay for you to assume that the cathode is one the right and the anode is on the left.
- Sun Mar 08, 2020 10:09 pm
- Forum: Balancing Redox Reactions
- Topic: e- amount
- Replies: 9
- Views: 623
Re: e- amount
The number of electrons should be balanced on both sides. You can multiply to get them to equal each other.
- Sun Mar 08, 2020 5:29 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Review Sessions
- Replies: 6
- Views: 354
Re: Final Review Sessions
This is what I found for the review sessions days and times: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Final_Review_Sessions_14B.pdf
- Sun Mar 01, 2020 9:30 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: first order
- Replies: 8
- Views: 616
Re: first order
For a first order reaction the graph has -k slope and the graph is linear. The reaction rate is proportional to one of the reactants concentration.
- Sun Mar 01, 2020 9:22 pm
- Forum: Phase Changes & Related Calculations
- Topic: Van't Hoff Eq
- Replies: 8
- Views: 653
Re: Van't Hoff Eq
It would probably be helpful to know how to derive it, but you would probably be okay just knowing the equations relationships.
- Sun Mar 01, 2020 9:09 pm
- Forum: Biological Examples (*DNA Structural Transitions, etc.)
- Topic: Examples Expected to Know
- Replies: 15
- Views: 1795
Re: Examples Expected to Know
I would think examples that we are expected to know would be in our notes or possibly from a homework question. For 14A the biological examples that we got on exams were covered in class.
- Sun Mar 01, 2020 8:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: HW 9
- Replies: 5
- Views: 400
Re: HW 9
For homework 9 I would think you can do homework from the topics that are going to be on test 2 in order to get some more practice in (2nd and 3rd laws of thermodynamics 2nd page and electrochemistry), or you can do homework from kinetics.
- Sun Mar 01, 2020 8:03 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 19
- Views: 904
Re: Test 2
Test 2 will only cover from the midterm up until the material we covered before kinetics.
- Sun Feb 23, 2020 9:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Extra Credit
- Replies: 17
- Views: 917
Re: Extra Credit
There are no extra credit opportunities. In 14A for Lavelle extra credit wasn't offered and it's not in the syllabus, so I assume there won't be any opportunities for extra credit.
- Sun Feb 23, 2020 9:19 pm
- Forum: Ideal Gases
- Topic: Conjugate acid and bases
- Replies: 7
- Views: 526
Re: Conjugate acid and bases
A conjugate base will have one less proton than the acid and the conjugate acid will have one more H+ than the base.
- Sun Feb 23, 2020 9:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cathode vs Anode
- Replies: 11
- Views: 887
Re: Cathode vs Anode
The cathode is where reduction occurs and the anode is where oxidation occurs. I don't think it necessarily matters what side of the diagram it is on, but the anode is usually on the left side of the diagram and the cathode is on the right side.
- Sun Feb 23, 2020 4:01 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous
- Replies: 23
- Views: 1172
Re: Spontaneous
When delta G is negative the reaction is spontaneous, but when delta G is positive the reaction is not spontaneous. When delta G is equal to 0 then the reaction is not spontaneous because it is at equilibrium.
- Sun Feb 23, 2020 3:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Material
- Replies: 16
- Views: 1013
Re: Test 2 Material
Test 2 won't cover material that we'll learn this coming week. The test will cover material from after the midterm, which is the second page of outline 4 and outline 5.
- Sun Feb 16, 2020 5:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure and Moles
- Replies: 7
- Views: 414
Re: Pressure and Moles
In order to see which way the reaction will shift you would count the coefficients.
- Sun Feb 16, 2020 5:21 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: 3/2R & 5/2R
- Replies: 9
- Views: 675
Re: 3/2R & 5/2R
Cp and Cv are used in finding the heat capacity. Cp is for constant pressure and Cv is for constant volume.
- Sun Feb 16, 2020 5:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: grading curve
- Replies: 10
- Views: 646
Re: grading curve
There is not a curve, but in order to pass the class with a C- you need at least a 50% for your overall grade.
- Sun Feb 16, 2020 5:13 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: delta h and constant temp and pressure
- Replies: 4
- Views: 314
Re: delta h and constant temp and pressure
At constant pressure deltaH will be equal to q and at constant pressure it is for a phase change.
- Sun Feb 16, 2020 5:04 pm
- Forum: Ideal Gases
- Topic: pv=nrt
- Replies: 19
- Views: 1131
Re: pv=nrt
Yes, this can be used. You would need to plug in the standard temperature and pressure (273 K and 1 atm).
- Sun Feb 09, 2020 9:31 pm
- Forum: Calculating Work of Expansion
- Topic: Midterm equation sheet
- Replies: 16
- Views: 689
Re: Midterm equation sheet
We will get the same equation sheet that is on his 14B website.
- Sun Feb 09, 2020 9:27 pm
- Forum: Ideal Gases
- Topic: Gas constant
- Replies: 10
- Views: 515
Re: Gas constant
You will want to use the constant that has the units that apply to the problem you are solving; you will want the units to cancel to give you the unit you want your answer to be in.
- Sun Feb 09, 2020 9:03 pm
- Forum: Ideal Gases
- Topic: Change in pressure
- Replies: 7
- Views: 497
Re: Change in pressure
If the pressure is increased the reaction would want to go back to equilibrium, so the reaction will shift to the side with fewer gas particles. If the pressure were to decrease then the reaction would go towards the side with more gas particles.
- Sun Feb 09, 2020 8:53 pm
- Forum: Ideal Gases
- Topic: reversing reactions
- Replies: 83
- Views: 4881
Re: reversing reactions
For a reverse reaction the value of K would be 1/K which is the inverse.
- Sun Feb 09, 2020 8:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Content
- Replies: 6
- Views: 348
Re: Midterm Content
I believe that will be included, but like others have said before the midterm will cover content from the the first outline all the way up until the first page of outline 4. The content all the way until this past Friday's lecture will be included.
- Sun Feb 02, 2020 9:59 pm
- Forum: Phase Changes & Related Calculations
- Topic: Question about Internal Energy
- Replies: 2
- Views: 132
Re: Question about Internal Energy
Yes, I believe your line of thinking is correct. :) That is what I have in my notes.
- Sun Feb 02, 2020 9:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4A. 3 part c)
- Replies: 1
- Views: 160
Re: 4A. 3 part c)
I am pretty sure you are correct and the answer should be 28 J. I found an old post on chemistry community and that was said to be the correct answer. Also, in my solution manual (old one but the same question) the answer is 28 J. Older post with this question: https://lavelle.chem.ucla.edu/forum/vi...
- Sun Feb 02, 2020 8:50 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Quadratic Equation
- Replies: 5
- Views: 442
Re: Quadratic Equation
Like others have said, you would use the quadratic formula when you have x squared and you need to find the value of x. I found this to be helpful: https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Equil...
- Sun Feb 02, 2020 8:42 pm
- Forum: Ideal Gases
- Topic: PV=nRT
- Replies: 74
- Views: 4238
Re: PV=nRT
P is pressure, V is volume, n is the number of moles, R is the gas constant (it'll be given to us on the equations and constants sheet), and T is temperature.
- Sun Feb 02, 2020 8:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test 1
- Replies: 6
- Views: 226
Re: Test 1
If Q is greater than K, then the reaction will go towards the reactants. If Q is less than K then the reaction will go towards the products.
- Sun Jan 26, 2020 5:54 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 6
- Views: 123
Re: Bond Enthalpies
They were used as an example in lecture, so we won't be expected to draw them.
- Sun Jan 26, 2020 5:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pressure and equilibrium
- Replies: 9
- Views: 247
Re: Pressure and equilibrium
If the pressure is increased the reaction will go towards the side with fewer gas particles. If you decrease the pressure the reaction will go to the side with more gas particles.
- Sun Jan 26, 2020 5:41 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam Burns
- Replies: 9
- Views: 634
Re: Steam Burns
This helped explain it for me: http://scienceline.ucsb.edu/getkey.php?key=1322 More energy is released in a phase change from a gas to a liquid (steam would turn to liquid once it touches skin) compared to boiling water touching skin because it doesn't undergo a phase change (less energy released). ...
- Sun Jan 26, 2020 5:20 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam vs Water
- Replies: 4
- Views: 179
Re: Steam vs Water
For water to go from a gas to a liquid more energy is required. When the gas turns to a liquid on skin more energy is released than boiling water hitting skin because the boiling water doesn't undergo a phase change. This explains it further: http://scienceline.ucsb.edu/getkey.php?key=1322
- Sun Jan 26, 2020 4:54 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: suggestions
- Replies: 16
- Views: 547
Re: suggestions
I find that the Organic Chemistry Tutor really helps, and he does practice problems in the videos too. If you wanted more practice the problems in the book might help since you can check the odd numbered ones in the solution manual.
- Sun Jan 19, 2020 10:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Q
- Replies: 14
- Views: 350
Re: K vs Q
K is used when the reaction is at equilibrium and Q can be used for other random times in the reaction. Q can be compared to K to see which direction the reaction will go.
- Sun Jan 19, 2020 10:04 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q < K
- Replies: 16
- Views: 806
Re: Q < K
When Q<K you have more reactants, so more products form.
- Sun Jan 19, 2020 9:58 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: K less than 10^-3
- Replies: 5
- Views: 282
Re: K less than 10^-3
Since K is less than 10^-3 more reactants are at equilibrium and the reaction sits to the left.
- Sun Jan 19, 2020 9:45 pm
- Forum: Ideal Gases
- Topic: R Constant
- Replies: 18
- Views: 1057
Re: R Constant
The R constant will be provided on the "Constants and Formulas" worksheet which can be found on the 14B class website and will be provided on tests and midterms, so we will not have to remember it. The constant can change depending on what units it is in, but different unit forms are also ...
- Sun Jan 19, 2020 9:33 pm
- Forum: Ideal Gases
- Topic: Topics on Test 1
- Replies: 37
- Views: 1303
Re: Topics on Test 1
I believe in lecture Lavelle said that test 1 will be outline 1 and 2, which is chemical equilibrium and acids and bases.
- Sun Jan 12, 2020 8:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kp
- Replies: 6
- Views: 400
Re: Kp
Kp is used when dealing with gases, it is the equilibrium constant calculated from the partial pressures.
- Sun Jan 12, 2020 7:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: memorization
- Replies: 12
- Views: 574
Re: memorization
I doubt we'll have to memorize any K values. If anything we'll be given that information if it is required to solve a problem.
- Sun Jan 12, 2020 7:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test One Content
- Replies: 6
- Views: 296
Re: Test One Content
I believe we will be tested on outline 1 and outline 2 (or at least parts of outline 2 depending on how far we get). He does let us know what we'll be tested on, but if anything your TA should know too. :) I believe the TAs make the tests so homework problems might not be on the test but they'll be ...
- Sun Jan 12, 2020 7:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: General HW question
- Replies: 9
- Views: 365
Re: General HW question
It depends on the TA I think. Last quarter my TA graded on correctness but others graded on completeness.
- Sun Jan 12, 2020 7:34 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Test 1
- Replies: 6
- Views: 217
Re: Test 1
Test 1 will be given in your discussion section during week 3.
- Sat Dec 07, 2019 3:28 pm
- Forum: Naming
- Topic: Transition Metal Latin Names
- Replies: 3
- Views: 910
Re: Transition Metal Latin Names
I think these are all/the majority of the transition metals with Latin names (this applies when they are in anionic complexes):
Iron - Ferrate
Copper - Cuprate
Lead - Plumbate
Silver - Argentate
Gold - Aurate
Tin - Stannate
Iron - Ferrate
Copper - Cuprate
Lead - Plumbate
Silver - Argentate
Gold - Aurate
Tin - Stannate
- Sat Dec 07, 2019 2:33 pm
- Forum: Naming
- Topic: Naming quizlet
- Replies: 41
- Views: 1695
Re: Naming quizlet
Thank you so much this is really helpful!
- Sat Dec 07, 2019 2:31 pm
- Forum: Sigma & Pi Bonds
- Topic: Marshmallow 41.C
- Replies: 3
- Views: 404
Re: Marshmallow 41.C
I think at the review session they said the answer was C=O because the the atomic radius of oxygen is smaller so it'll form a stronger bond.
- Sat Dec 07, 2019 2:01 pm
- Forum: Properties of Electrons
- Topic: Mass of an electron
- Replies: 9
- Views: 749
Re: Mass of an electron
You do not need to remember the mass of an electron since it is one of the constants that will be given on the formula sheet provided. The formula sheet will the same one from the midterm.
- Sat Dec 07, 2019 1:51 pm
- Forum: Significant Figures
- Topic: pH sig figs
- Replies: 9
- Views: 578
Re: pH sig figs
I think for pH sig figs you count the sig figs after the decimal point, at least that's what I remember hearing from a review session. I found an old post that might answer your question better: https://lavelle.chem.ucla.edu/forum/viewtopic.php?t=790
- Sun Dec 01, 2019 8:29 pm
- Forum: Naming
- Topic: Final Exam?
- Replies: 20
- Views: 1076
Re: Final Exam?
There was an email sent out that said review sessions would begin December 3rd, but the rooms and times haven't been announced yet, they will be announced Monday in class.
- Sun Dec 01, 2019 8:26 pm
- Forum: Naming
- Topic: Final Exam?
- Replies: 20
- Views: 1076
Re: Final Exam?
The final is cumulative and good review would be homework problems, tests, the midterm, and past final questions.
- Sun Dec 01, 2019 8:00 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: Test Grades
- Replies: 6
- Views: 411
Re: Test Grades
It should probably be posted in the next few days, but my TA already input grades so when grades are input probably depends on the TAs.
- Sun Dec 01, 2019 7:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma Bond
- Replies: 10
- Views: 585
Re: Sigma Bond
Single bonds are sigma bonds, in double bonds there is a sigma and pi bond, and in triple bonds there are two pi bonds and one sigma bond.
- Sun Dec 01, 2019 7:45 pm
- Forum: SI Units, Unit Conversions
- Topic: midterm/final
- Replies: 18
- Views: 1421
Re: midterm/final
Based on the midterm there will probably be more calculation problems, but conceptual problems will be on the final as well.
- Sun Nov 24, 2019 8:52 pm
- Forum: Dipole Moments
- Topic: Melting points
- Replies: 15
- Views: 1284
Re: Melting points
Intermolecular forces affect the melting points, so the stronger the intermolecular force the higher the melting point and vice versa.
- Sun Nov 24, 2019 8:49 pm
- Forum: Electronegativity
- Topic: Increasing/Decreasing Electronegativity
- Replies: 14
- Views: 2700
Re: Increasing/Decreasing Electronegativity
Electronegativity increases up and to the right of the periodic table. It also helps to remember that fluorine is the most electronegative element so electronegativity increases in the direction of fluorine.
- Sun Nov 24, 2019 8:44 pm
- Forum: Lewis Structures
- Topic: Bent or Angular?
- Replies: 18
- Views: 1093
Re: Bent or Angular?
The two terms are synonymous, so you can use either one. :)
- Sun Nov 24, 2019 8:39 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Calculating quantum numbers
- Replies: 4
- Views: 443
Re: Calculating quantum numbers
If you're asked to give the quantum numbers for an atom or an ion you can write out the electron configuration of it and from there you can easily find out the quantum numbers.
- Sun Nov 24, 2019 8:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on Cenrtral Atom
- Replies: 11
- Views: 604
Re: Lone Pairs on Cenrtral Atom
Since lone pairs repel the other bonds around the central atom the bond angle between bonds will decrease since they arrange themselves to be away from the lone pair(s).
- Sun Nov 17, 2019 5:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 2
- Replies: 19
- Views: 832
Test 2
When determining the molecular shape and bond angles do the Lewis structures have to be drawn as accurately as possible?
- Sun Nov 17, 2019 5:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs vs Bonding Pairs
- Replies: 2
- Views: 136
Re: Lone Pairs vs Bonding Pairs
I am not sure about “taking up space,” but lone pairs have a high repulsion force so they distort the bond angles and force the bonding pairs in the molecule closer together.
- Sun Nov 17, 2019 5:04 pm
- Forum: Trends in The Periodic Table
- Topic: trends on test 2
- Replies: 4
- Views: 279
Re: trends on test 2
We may not be asked specific questions on periodic trends like we were on the midterm, but the topics we will be tested on rely on knowledge that comes from the periodic table. Since the test will cover material after the midterm we will be focusing on outline 4 and a little bit on outline 3 (things...
- Sun Nov 17, 2019 4:57 pm
- Forum: Significant Figures
- Topic: Sig Figs on Tests
- Replies: 24
- Views: 2179
Re: Sig Figs on Tests
The number of significant figures you put your answer in is based on the question, so the least amount of significant figures in the question is used.
- Sun Nov 17, 2019 4:42 pm
- Forum: Hybridization
- Topic: Homework Outline for Test
- Replies: 5
- Views: 271
Re: Homework Outline for Test
The majority of the test will probably focus mainly on outline 4 (molecular shape and structure) and a little bit of material from outline 3 may be on there too since things like London forces, dispersion forces, etc. were covered after the midterm I believe.
- Sun Nov 10, 2019 4:46 pm
- Forum: Trends in The Periodic Table
- Topic: Electronegativity
- Replies: 9
- Views: 478
Re: Electronegativity
Yes, you are correct. :) Electronegativity increases up and to the right of the periodic table.
- Sun Nov 10, 2019 4:35 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability Trends
- Replies: 4
- Views: 152
Re: Polarizability Trends
Iodine exists as a solid at room temperature because the strength of London forces are in line with iodine's large electron cloud and polarizability. I can't explain it that well, I'm sorry! But this article might be more helpful: https://socratic.org/questions/elemental-iodine-is-a-solid-at-room-te...
- Sun Nov 10, 2019 4:29 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability Trends
- Replies: 4
- Views: 152
Re: Polarizability Trends
The greater the number of electrons there are and the greater distance of electrons from the nuclear charge, the less control the nuclear charge has on charge distribution, therefore there is an increased polarizability of the atom.
- Sun Nov 10, 2019 4:23 pm
- Forum: SI Units, Unit Conversions
- Topic: Homework from Outline 3 due?
- Replies: 5
- Views: 471
Re: Homework from Outline 3 due?
You should be fine doing homework from outline 3, since I don't think we've covered material from outline 4 yet. :)
- Sun Nov 10, 2019 4:13 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Magnetic Quantum numbers
- Replies: 13
- Views: 765
Re: Magnetic Quantum numbers
The magnetic quantum number (ml) is based on l, the angular momentum quantum number, and ranges from -l to l. So, if l=1 then ml=-1,0,1.
- Sun Nov 03, 2019 9:22 pm
- Forum: Bond Lengths & Energies
- Topic: Strength of Bonds
- Replies: 16
- Views: 629
Re: Strength of Bonds
Shorter bonds are stronger than longer bonds. The strength for three types is triple bond>double bond>single bond, so the stronger bonds are shorter.
- Sun Nov 03, 2019 9:16 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Aufbau vs Hunds
- Replies: 6
- Views: 487
Re: Aufbau vs Hunds
Afbau states that the lower energy levels must be occupied before the higher ones can be filled and Hund’s rule states that the orbitals must be filled with one electron before they can be paired.
- Sun Nov 03, 2019 8:50 pm
- Forum: Properties of Light
- Topic: Midterm Exam
- Replies: 21
- Views: 586
Re: Midterm Exam
I think the midterm will be free response/open ended questions. If there are any multiple choice questions there will probably only be a few.
- Sun Nov 03, 2019 8:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Finding electron configurations
- Replies: 4
- Views: 243
Re: Finding electron configurations
You would write the noble gas that comes before the element you are trying to write the electron configuration number then write the electron configuration for additional electrons in the regular way. I found watching videos helped me more than reading explanations so that might help you too! This o...
- Sun Nov 03, 2019 8:29 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Homework Problem 1E. 5
- Replies: 2
- Views: 102
Re: Homework Problem 1E. 5
This is false because Zeffe is affected by the number of electrons in an atom because the electrons are shielded from the full attraction of the nucleus. This occurs because the electron electron repulsions work against the pull of the nucleus.
- Sun Oct 27, 2019 10:47 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Midterm
- Replies: 5
- Views: 255
Re: Midterm
Thank you! Do you have any recommendations for how to review how to write the shorthand configuration?
- Sun Oct 27, 2019 10:44 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Midterm
- Replies: 5
- Views: 255
Midterm
For the midterm will we have to know how to write the shorthand electron configuration of an element?
- Sun Oct 27, 2019 10:30 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 3
- Views: 170
Resonance
When we draw the resonance structures do we have to draw out all of the possible ways or is a resonance hybrid sufficient enough on its own? Or would we have to draw all of the structures plus the hybrid?
- Sun Oct 27, 2019 9:57 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework
- Replies: 13
- Views: 625
Re: Homework
I'm pretty sure you can do problems from both since we covered both sections. Like someone said before it might be beneficial to do problems from the chemical bonds section to get more practice on those problems since it'll be on the midterm.
- Sun Oct 27, 2019 9:39 pm
- Forum: *Particle in a Box
- Topic: TEST 2
- Replies: 14
- Views: 1348
Re: TEST 2
I think one of the suggested ways to prepare for an exam was to work through the assigned homework problems. I would do those problems and study with someone else so we could ask each other questions and teach each other.
- Sun Oct 20, 2019 10:00 pm
- Forum: Properties of Light
- Topic: light regions
- Replies: 4
- Views: 175
Re: light regions
Is there an easy way to memorize the regions with the corresponding values? Do you use any mnemonic devices?
- Sun Oct 20, 2019 9:43 pm
- Forum: Photoelectric Effect
- Topic: 1B.3
- Replies: 3
- Views: 116
Re: 1B.3
The answer would be d, because the photoelectric effect was explained to have electromagnetic radiation and it’s composed of photons that each have fixed energy that equals to h*v.
- Sun Oct 20, 2019 9:35 pm
- Forum: Photoelectric Effect
- Topic: hw 1B.15 part c
- Replies: 3
- Views: 247
Re: hw 1B.15 part c
I think you would use the wavelength you got from part c and find where it is on the electromagnetic spectrum. There is a figure and table in 1A.2 Electromagnetic Radiation that you can refer to.
- Sun Oct 20, 2019 8:55 pm
- Forum: Properties of Light
- Topic: Next test
- Replies: 23
- Views: 1045
Re: Next test
There is a constants and equations sheet posted on the website and I think that is the one we will be given on exams.
link: https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
link: https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
- Sun Oct 20, 2019 8:47 pm
- Forum: Properties of Light
- Topic: What are the units of hertz
- Replies: 41
- Views: 1999
Re: What are the units of hertz
Hertz is cycles per second and it can be written as 1/s or s^-1
- Sun Oct 13, 2019 9:00 pm
- Forum: Significant Figures
- Topic: Significant Figures on Test 1
- Replies: 3
- Views: 270
Re: Significant Figures on Test 1
I don't think sig figs were really important for this test, but if they were to grade based on that you would just base your sig figs off the values given to you in the question. I hope this helps :)
- Sun Oct 13, 2019 8:51 pm
- Forum: Significant Figures
- Topic: Tests and Significant Figures
- Replies: 6
- Views: 332
Re: Tests and Significant Figures
I think you use the least amount of significant figures based on the values of what is given in the question, but I would definitely check out the post mentioned post to make sure. :)
- Sun Oct 13, 2019 8:41 pm
- Forum: Properties of Light
- Topic: Quick question on equations
- Replies: 5
- Views: 254
Quick question on equations
Just to clarify, we are going to be expected to know the equations we have been given in class regarding light, energy, etc. right? Just asking because on the test they did give us an equation sheet with most of the equations.
- Sun Oct 13, 2019 8:31 pm
- Forum: Photoelectric Effect
- Topic: Question about Energy Threshold
- Replies: 7
- Views: 210
Re: Question about Energy Threshold
The energy threshold won’t be enough to create the photoelectric effect but the energy will be conserved. The energy might be reabsorbed or refracted.
- Sun Oct 13, 2019 8:24 pm
- Forum: Photoelectric Effect
- Topic: Question about Energy Threshold
- Replies: 7
- Views: 210
Re: Question about Energy Threshold
I just want to make sure I'm understanding your question :) are you asking what happens if the photon doesn't have enough energy to remove the electron?
- Thu Oct 03, 2019 7:07 pm
- Forum: SI Units, Unit Conversions
- Topic: Formula Names
- Replies: 7
- Views: 401
Re: Formula Names
I'm guessing if there are any questions in the homework like that then it'll be considered fair game. There is review in the textbook which would probably help with this or other resources like khan academy really help.
- Thu Oct 03, 2019 6:37 pm
- Forum: SI Units, Unit Conversions
- Topic: Chemistry Community Question
- Replies: 3
- Views: 123
Re: Chemistry Community Question
I heard Dr. Lavelle say during lecture that they are due Sunday night by 11:59pm
- Thu Oct 03, 2019 6:29 pm
- Forum: SI Units, Unit Conversions
- Topic: Clarification for SI Units
- Replies: 4
- Views: 228
Re: Clarification for SI Units
You wrote the correct prefixes for each conversion :) and I think to be safe you should know them in order to convert during tests, midterms, etc. in case it is required. Also, Dr. Lavelle mentioned that in chemistry we won't be using the larger units, like giga, often.
- Thu Oct 03, 2019 5:53 pm
- Forum: Balancing Chemical Reactions
- Topic: Question on L39
- Replies: 1
- Views: 106
Re: Question on L39
In order to find the total mass of the tin oxide you would use the total mass of the crucible and the product (28.35 g) and subtract that by mass of the crucible (26.45 g) to get the mass of the product formed. 28.35 g - 26.45 g = 1.90 g In the question they gave you the mass of tin (1.50 g Sn) so t...
- Thu Oct 03, 2019 5:11 pm
- Forum: Significant Figures
- Topic: sig figs in calculations
- Replies: 4
- Views: 210
sig figs in calculations
Should I just use significant figures in my final answer or should I use them throughout the entire process leading up to my answer?