Search found 61 matches
- Thu Mar 14, 2019 7:32 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3891014
Re: Post All Chemistry Jokes Here
Lose an electron? Gotta keep ion it.
- Thu Mar 14, 2019 7:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: units
- Replies: 7
- Views: 1019
Re: units
Pressure has a variety of units. Because of this, I double check the units of all the givens so I know which pressure unit to use when solving a problem.
- Thu Mar 14, 2019 7:24 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Intermediate vs catalyst
- Replies: 8
- Views: 858
Re: Intermediate vs catalyst
Catalyst: There to begin with
Intermediate: Formed, not reactant/product
Intermediate: Formed, not reactant/product
- Thu Mar 14, 2019 7:15 pm
- Forum: Student Social/Study Group
- Topic: Studying for the Final
- Replies: 25
- Views: 2870
Re: Studying for the Final
I have been going to UA sessions and doing plenty of homework problems! That way, I am exposed to the different questions that may be asked during the exam.
- Wed Mar 06, 2019 9:49 pm
- Forum: Van't Hoff Equation
- Topic: Temp Units
- Replies: 11
- Views: 1366
Re: Temp Units
Kelvin! When you write out the Van’t Hoff equation, the K cancels out from the R constant.
- Wed Mar 06, 2019 9:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Curve
- Replies: 11
- Views: 1795
Re: Class Curve
On the syllabus, it states, "50% or higher is required to pass with a C- or higher." Therefore, if your overall grade in the class is 50% or higher, you pass the class. However, I am not entirely sure about the breakdown...
- Wed Mar 06, 2019 9:41 pm
- Forum: Second Order Reactions
- Topic: graph for second order
- Replies: 7
- Views: 803
Re: graph for second order
The graph for the second-order reaction is a straight positive slope line with an equation of k=-slope.
- Wed Mar 06, 2019 9:38 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test #2
- Replies: 10
- Views: 1080
Re: Test #2
Students should get their test #2 this week (Week 9) during their section time.
- Tue Feb 19, 2019 5:56 pm
- Forum: Student Social/Study Group
- Topic: Test
- Replies: 17
- Views: 1602
Re: Test
My TA specified Test 2 will most likely circulate thermodynamics. However, I am sure Gibbs free energy will be a part of it too since we are currently learning about it.
- Tue Feb 19, 2019 5:54 pm
- Forum: Student Social/Study Group
- Topic: Best Midterm Review
- Replies: 7
- Views: 773
Re: Best Midterm Review
Personally, I think attending UA sessions are really helpful (i.e., Lyndon and Karen). The UAs usually provide you worksheets for you to work on prior to the workshop so you get a chance to practice the actual content. In addition, it is nice to have another former student's perspective on the actua...
- Tue Feb 19, 2019 5:53 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Final exam
- Replies: 8
- Views: 942
Re: Final exam
The final exam is on Sunday, March 17th from 11:30 AM -2:30 PM! Usually, Lavelle posts the exam locations near the date of the exam.
- Tue Feb 19, 2019 5:50 pm
- Forum: General Rate Laws
- Topic: test 3
- Replies: 6
- Views: 642
Re: test 3
Although it is not stated yet on the website, my TA specified Test 2 will most likely circulate thermodynamics. However, I am sure Gibbs free energy will be a part of it too since we are currently learning about it.
- Tue Feb 19, 2019 5:34 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: What to do when temperature isn't given
- Replies: 8
- Views: 905
Re: What to do when temperature isn't given
A common general temperature seen throughout problems is 25C. However, most of the time the temperature is given.
- Sun Feb 10, 2019 8:07 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Study Guides
- Replies: 15
- Views: 1287
Re: Study Guides
A lot of the UA sessions provide worksheets for students to use. For example, Lyndon and Karen provide online worksheets for student to access during their workshops or individual study time.
- Sun Feb 10, 2019 7:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Tutoring? [ENDORSED]
- Replies: 121
- Views: 292357
Re: Tutoring? [ENDORSED]
On some occasions, you can contact your TA and try scheduling an appointment outside of office hours to get further assistance.
jlinwashington1D wrote:Are there any one on one sessions ?
- Sun Feb 10, 2019 5:02 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 8
- Views: 930
Re: Midterm
Last Friday, Lavelle said everything up until entropy will be on the midterm.
- Sun Feb 10, 2019 5:00 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm [ENDORSED]
- Replies: 49
- Views: 4999
Re: Midterm [ENDORSED]
Personally, what really helps me prepping for exams attending UA workshops. There are a variety of selections (i.e., drop-in, workshops, step-up) for you to choose from depending on your mastery.
- Fri Feb 01, 2019 1:25 am
- Forum: Calculating Work of Expansion
- Topic: Work
- Replies: 5
- Views: 575
Re: Work
When given the term of work, I think of the amount of energy being transferred from one form to another in order to do something. Personally, some keywords that help when determining work are: work being done (positive), does/doing (negative).
- Fri Feb 01, 2019 1:22 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Work
- Replies: 3
- Views: 544
Re: Work
Personally, what helps me the most is by looking at the keywords the problem is giving me. For example, if I see "work being done", I automatically assume it is positive because there is energy being entered on a system.
- Fri Feb 01, 2019 1:18 am
- Forum: Phase Changes & Related Calculations
- Topic: J vs. kJ
- Replies: 9
- Views: 1103
Re: J vs. kJ
It depends on what the question is specifically asking. However, it is crucial to make sure that as you are solving a problem, all the units are consistent (i.e., if you are using just Joules, make sure it is just Joules.)
- Thu Jan 31, 2019 4:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: What Does U and q stand for?
- Replies: 9
- Views: 2394
Re: What Does U and q stand for?
ΔU = q+w
ΔU = Internal Energy
q = Net heat transfer in the system
w = Work being done in the system
ΔU = Internal Energy
q = Net heat transfer in the system
w = Work being done in the system
- Thu Jan 31, 2019 3:45 pm
- Forum: Phase Changes & Related Calculations
- Topic: Test #1
- Replies: 11
- Views: 994
Re: Test #1
Yes, your TA will distribute your test during this week's section.
- Thu Jan 31, 2019 3:45 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Work Question
- Replies: 4
- Views: 469
Re: Work Question
When I think of work, I think of the amount of energy transferred from one form to another in order to do something. Some keywords that help when determining work are: work being done (positive), does/doing (negative).
- Thu Jan 31, 2019 3:39 pm
- Forum: Ideal Gases
- Topic: atm vs. bar?
- Replies: 25
- Views: 2996
Re: atm vs. bar?
Both atm and bar are units of partial pressures of gases! However, it's important you stick to just one or the other when calculating equilibrium constant with pressure.
- Mon Jan 14, 2019 2:57 pm
- Forum: Ideal Gases
- Topic: R in PV=nRT
- Replies: 34
- Views: 7096
Re: R in PV=nRT
PV=nRT is the Ideal Gas Law equation. To answer your question, the R is the ideal gas law constant and there are varying corresponding values (for the most part, problems will specify which value to use.) Some examples can include bar or atm.
- Mon Jan 14, 2019 2:53 pm
- Forum: General Science Questions
- Topic: Lecture Powerpoints
- Replies: 9
- Views: 761
Re: Lecture Powerpoints
From my experience, the lecture slides are not posted anywhere. However, if you ever find yourself unable to keep up with the slides, Lavelle does have three lectures MWF that you can catch up on.
- Mon Jan 14, 2019 2:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test Dates
- Replies: 3
- Views: 405
Re: Test Dates
Test 1 starts Tuesday January 22 (Week 3) in discussion section and Test 2 starts Tuesday February 26 (Week 8) in discussion section.
- Mon Jan 14, 2019 2:47 pm
- Forum: Student Social/Study Group
- Topic: New to Lavelle
- Replies: 32
- Views: 5341
Re: New to Lavelle
Personally, I found going to the UA workshops very helpful. Depending on how you feel on the mastery of the course, you can choose which workshop fits for you (Step-Up, Drop-In, Workshop)! That being said, there are plenty of resources for you to be able to choose from to succeed in this class.
- Mon Jan 14, 2019 2:46 pm
- Forum: Ideal Gases
- Topic: Units
- Replies: 19
- Views: 1214
Re: Units
Always use Kelvin! If a problem states a temperature in Celsius (this is very common) or Fahrenheit, convert it to Kelvin.
- Mon Jan 14, 2019 2:42 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3891014
Re: Post All Chemistry Jokes Here
I don't trust atoms. I heard they make up everything.
- Mon Dec 03, 2018 8:55 pm
- Forum: Bronsted Acids & Bases
- Topic: Difference
- Replies: 2
- Views: 246
Re: Difference
Acid:
Bronsted-Lowry definition → Proton donor
Lewis definition → Accepts e- pair
Base:
Bronsted-Lowry definition → Proton acceptor
Lewis definition → Donates e- pair
Bronsted-Lowry definition → Proton donor
Lewis definition → Accepts e- pair
Base:
Bronsted-Lowry definition → Proton acceptor
Lewis definition → Donates e- pair
- Mon Dec 03, 2018 8:46 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs angular?
- Replies: 15
- Views: 1215
Re: Bent vs angular?
Both bent and angular are the same shape!
- Mon Dec 03, 2018 8:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39575
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Hi! Thank you for the workshop and answering all of my burning questions this quarter. I appreciate it!
- Mon Dec 03, 2018 8:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39575
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Hi! Thank you for the workshop and answering all of my burning questions this quarter. I appreciate it!
- Mon Dec 03, 2018 8:44 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3891014
Re: Post All Chemistry Jokes Here
I try to tell Chemistry jokes but there are no reactions.
- Mon Dec 03, 2018 4:40 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Degeneracy
- Replies: 6
- Views: 714
Re: Degeneracy
Degeneration refers to all the orbitals having the same energy. For example, the three orbitals in 3p are considered degenerate because they have the same energy. Hope this helps.
- Mon Dec 03, 2018 4:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar
- Replies: 12
- Views: 2053
Re: Square Planar
The bond angles of a square planar are 90 degrees.
- Mon Dec 03, 2018 4:32 pm
- Forum: Naming
- Topic: Naming the Shape
- Replies: 6
- Views: 635
Re: Naming the Shape
Personally, I think drawing the Lewis structure is most helpful when determining the formal charge. Visually seeing the bonds and lone pairs of each element help reassure you are calculating the charge correctly.
- Sat Nov 24, 2018 9:59 pm
- Forum: Electronegativity
- Topic: octet expansion
- Replies: 2
- Views: 526
Re: octet expansion
A quick way to think of the "octet expansion involving d-orbitals": Elements that would be considered to have an expanded octet are those in period 3 and beyond because these specific elements can/are able to hold electrons in the d-orbital shell.
Hope this helps.
Hope this helps.
- Sat Nov 24, 2018 9:53 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 8
- Views: 3537
Re: Formal Charge
Personally, the way I look at calculating the formal charge is through this equation: Number of valence electrons - (Lone pairs + Bonds) # of valence electrons: Given through the periodic table based on their period position (Ex: Carbon has 4 V.E. because it is located in Period 4.) Lone pairs: The ...
- Sat Nov 24, 2018 9:48 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Degeneracy
- Replies: 4
- Views: 5240
Re: Degeneracy
When speaking in terms of degeneration, this refers to all the orbitals having the same energy. For example, the three orbitals in 3p are considered to be degenerate because they have the same energy.
- Sat Nov 24, 2018 9:44 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework for week 9
- Replies: 11
- Views: 1192
Re: Homework for week 9
I think as long as you have your total amount of 14 problems, you should be good.
- Sat Nov 24, 2018 9:42 pm
- Forum: Electronegativity
- Topic: Nonmetals?
- Replies: 6
- Views: 754
Re: Nonmetals?
Nonmetals are usually more electronegative than metals because these specific elements are closer to a full outer shell. Additionally, those who have a higher amount of valence electrons (which is determined through their position in the periodic table) are more electronegative.
- Sun Nov 11, 2018 8:52 pm
- Forum: Lewis Structures
- Topic: Expanded Octets
- Replies: 9
- Views: 2847
Re: Expanded Octets
Elements that would be considered to have an expanded octet are those in period 3 and beyond because these specific elements can/are able to hold electrons in the d-orbital shell.
- Sun Nov 11, 2018 8:49 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Equation
- Replies: 13
- Views: 3449
Re: Formal Charge Equation
The way I look at the formal charge equation is: Number of valence electrons - (Lone pairs + Bonds) # of valence electrons: Given through the periodic table based on their period position Lone pairs: The number of "dots" around an element Bonds: The number of "lines" in between t...
- Sun Nov 11, 2018 8:36 pm
- Forum: Bond Lengths & Energies
- Topic: Tests
- Replies: 5
- Views: 646
Re: Tests
Yes!
Test #3: Starting Week 9 - During your discussion section
Final: Finals week - Sunday, December 9 11:30 AM - 2:00 PM
Test #3: Starting Week 9 - During your discussion section
Final: Finals week - Sunday, December 9 11:30 AM - 2:00 PM
- Thu Nov 01, 2018 3:45 pm
- Forum: Lewis Structures
- Topic: Most stable lewis
- Replies: 3
- Views: 396
Re: Most stable lewis
The most stable Lewis structure is determined by finding a structure that has the least formal charge on each atom. In order to find the formal charge of an atom, you use this formula: Formal Charge = [# of valence electrons on atom] – [non-bonded electrons + number of bonds]
- Thu Nov 01, 2018 3:39 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Degeneration
- Replies: 3
- Views: 471
Re: Degeneration
Degeneration refers to all the orbitals having the same energy. For example, the three orbitals in 3p are considered degenerate because they have the same energy.
- Thu Nov 01, 2018 3:31 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 12
- Views: 1015
Re: Speed of Light
Nothing is faster than the speed of light. There is a theory that only particles with a zero rest mass may travel at the speed of light.
- Sat Oct 27, 2018 5:02 pm
- Forum: Student Social/Study Group
- Topic: Studying
- Replies: 7
- Views: 800
Re: Studying
I personally found attending TA office hours helpful. From the TA office hours I have been to, I was able to get a lot of my burning questions answered when I was not able to ask them during lecture or discussion. The TAs were able to personally guide me through different problems (extremely helpful...
- Sat Oct 27, 2018 4:57 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Meaning of Z
- Replies: 5
- Views: 589
Re: Meaning of Z
For the most part, Z symbolizes the atomic number (or it is also correct referring to it as the number of protons) of an element.
- Wed Oct 24, 2018 12:53 am
- Forum: Trends in The Periodic Table
- Topic: Test 2
- Replies: 3
- Views: 336
Re: Test 2
Based on the website, it states, " Test 2 covers all quantum material up to and including quantum numbers (all quantum material up to the end of Week 3 ." Additionally, you can use https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Chem14A_Outline2_The_Quantum_World.pdf to h...
- Sun Oct 21, 2018 6:41 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 16
- Views: 852
Re: Work Function
Josephine Lu 1L wrote:Is the unit of work function Joules, or Joules per photon?
The unit for work function is Joules. Moreover--work function is a measure of energy, and energy is measured in the units of Joules.
- Thu Oct 18, 2018 1:39 pm
- Forum: Einstein Equation
- Topic: The symbol v?
- Replies: 16
- Views: 8903
Re: The symbol v?
Just to reiterate the comment above, there is a difference between the symbols of frequency and velocity. Furthermore, frequency is represented by the Greek letter nu (similar to v but has a curly/curvy edge to it) and velocity is represented by a lowercase v.
- Tue Oct 16, 2018 11:08 pm
- Forum: Properties of Light
- Topic: Test 2
- Replies: 17
- Views: 1343
Re: Test 2
To answer some of the questions above, Test 2 will start on Tuesday, October 23 during your discussion section (next week!)
- Thu Oct 11, 2018 10:23 am
- Forum: Einstein Equation
- Topic: sig fig numbers
- Replies: 4
- Views: 342
Re: sig fig numbers
When it comes to significant numbers, the rules of thumb I use are:
Multiplication/division: Answers will be in the least number of significant figures
Addition/subtraction: Answers will be in the least number of decimal places
Hope this helps!
Multiplication/division: Answers will be in the least number of significant figures
Addition/subtraction: Answers will be in the least number of decimal places
Hope this helps!
- Thu Oct 11, 2018 10:17 am
- Forum: Limiting Reactant Calculations
- Topic: Test 1
- Replies: 8
- Views: 1162
Re: Test 1
I definitely think practice problems help! Not only are you strengthing your skills with the topics you are studying for, but you can familiarize yourself with the way problems can be written for that specific topic and get used to the different terms. In addition, if you feel like you may be strugg...
- Thu Oct 11, 2018 10:11 am
- Forum: Significant Figures
- Topic: Calculators
- Replies: 20
- Views: 1954
Re: Calculators
Personally, I always brought a scientific calculator with me for an exam/test. On the Chem14A syllabus, it does say you may only bring "non-programmable and non-graphing calculators". Hope this helps!
- Sat Oct 06, 2018 8:20 pm
- Forum: Significant Figures
- Topic: Rounding numbers ending in 5
- Replies: 9
- Views: 905
Re: Rounding numbers ending in 5
Personally, I have always used the method of rounding up whenever the ending number is above 5, so I think you should be good. For your specific example, I would have rounded 2.65 to 2.7.
- Sat Oct 06, 2018 8:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Tutoring? [ENDORSED]
- Replies: 121
- Views: 292357
Re: Tutoring? [ENDORSED]
To add on to all the comments already posted about the different tutoring programs offered at UCLA, I personally found attending TA office hours helpful. From the TA office hours I have been to, I was able to get a lot of my burning questions answered when I was not able to ask them during lecture o...
- Sat Oct 06, 2018 7:57 pm
- Forum: Empirical & Molecular Formulas
- Topic: homework problem F9
- Replies: 3
- Views: 281
Re: homework problem F9
To begin with, you would first convert the given mass percentages into grams. For example, 63.15% of Carbon would translate to 63.15 grams of Carbon. Following up with answering your question, you divide the number of grams of each element by their respective molar mass (in which can be found throug...