Search found 50 matches
- Wed Mar 11, 2020 4:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: final
- Replies: 14
- Views: 977
Re: final
I think we are all waiting for the same answers! Professor Lavelle said he would get back to us with more information soon! I think the answers will come when he sends another email.
- Tue Mar 10, 2020 4:38 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Review Sessions
- Replies: 2
- Views: 262
Re: Review Sessions
I think Dr. Lavelle will send a clarifying email soon.
- Mon Mar 09, 2020 11:19 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step
- Replies: 7
- Views: 472
Slow step
Will we be given the intermediate reactions? Or should we be able to tell from the original reaction? Also how do we tell which intermediate reaction is the slow one?
- Mon Mar 09, 2020 6:33 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell diagram
- Replies: 7
- Views: 428
Re: Cell diagram
Use the vertical line! Also make sure to add in the inert metal on both ends separated with another vertical line.
- Mon Mar 09, 2020 6:32 am
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 2
- Views: 276
Final
Do Lavelle’s 14B finals usually take the whole 3 hours to finish?
- Mon Mar 09, 2020 5:32 am
- Forum: Administrative Questions and Class Announcements
- Topic: Review session on Friday
- Replies: 3
- Views: 303
Review session on Friday
Will the review session Friday 6-9 be Bruin casted?
- Wed Mar 04, 2020 11:11 am
- Forum: Administrative Questions and Class Announcements
- Topic: Excellence in Chemistry Award!
- Replies: 27
- Views: 10018
Re: Excellence in Chemistry Award!
[img]IMG_1899.jpeg[/img]
- Sun Mar 01, 2020 8:19 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 3
- Views: 312
Re: Nernst Equation
start with the two different delta G equations. Set them equal to each other and solve for E. then separately Solve the delta G equation(the one with Estandard) for Estandard. youll then notice you can plug that into the equation you got for E. Also change p/r to q. That is the derivation of Nerst.
- Sun Mar 01, 2020 7:58 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: cell diagrams
- Replies: 8
- Views: 499
Re: cell diagrams
on page 550 of the book there is an example where the cathode and anode have flipped sides in the diagram. In class I believe Dr. Lavelle said to look at which one is being reduced and which one is being oxidized and that will tell you which one is the anode/cathode.
- Fri Feb 28, 2020 8:05 pm
- Forum: First Order Reactions
- Topic: Slopes of a plot
- Replies: 7
- Views: 1229
Re: Slopes of a plot
Yes the graph of the first order has a negative slope. The slope is -k and since k is always positive the slope is always negative for 1st order.
- Fri Feb 28, 2020 8:01 pm
- Forum: General Rate Laws
- Topic: Overall reaction order
- Replies: 4
- Views: 342
Overall reaction order
What do you set rate 1/rate 2 equal to when trying to find m or n. In the example from class, they set it equal to 2 so that it was 2^m= 2 and m was just 1. I’m confused how to know what to set 2^m equal to.
- Fri Feb 28, 2020 7:45 pm
- Forum: General Rate Laws
- Topic: Deriving the laws
- Replies: 5
- Views: 468
Deriving the laws
Each time we use the different laws, are we supposed to derive them from the start or are we allowed to plug and chug?
- Mon Feb 24, 2020 11:12 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 13
- Views: 700
Re: Test 2
Second page of the thermodynamics outline and all of the electrochemistry outline.
- Mon Feb 24, 2020 11:10 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: midterm
- Replies: 5
- Views: 484
Re: midterm
Can we go to any TA for our own?
- Mon Feb 24, 2020 11:09 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Today in lecture, Dr. Lavelle
- Replies: 4
- Views: 336
Re: Today in lecture, Dr. Lavelle
I loved that love! Thank you now I can down load it!!
- Fri Feb 21, 2020 12:01 pm
- Forum: General Science Questions
- Topic: What are Workshops?
- Replies: 10
- Views: 888
Re: What are Workshops?
Are step up sessions worth the time? I need help but I don’t have a lot of free time to go to a session that might just be the exact thing from class.
- Fri Feb 21, 2020 12:00 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation numbers
- Replies: 6
- Views: 441
Re: Oxidation numbers
Are all diatomic molecules neutral charge?
- Fri Feb 21, 2020 11:59 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standards
- Replies: 2
- Views: 214
Standards
What makes something a standard quality? When do I know to use standard vs not standard?
- Wed Feb 19, 2020 7:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: midterm 3C
- Replies: 4
- Views: 358
Re: midterm 3C
Yes! Bcs NH4CL dissociates, it produces more NH4 which is acidic. Having more of an acid will ultimately decrease the pH even if it’s a weak acid.
- Wed Feb 19, 2020 7:45 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible Reaction
- Replies: 6
- Views: 464
Re: Reversible Reaction
Most of the questions I’ve come across have stated that the process was reversible or nonreversible. Reversible reactions must be at constant temp as well and that’s why we use the equations for w that includes T not delta T.
- Wed Feb 19, 2020 7:40 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E as intensive property
- Replies: 5
- Views: 386
Re: E as intensive property
I think intensive means that the voltage difference doesn’t depend on the amount of times that the voltage occurs??
- Wed Feb 19, 2020 7:35 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpies of formation
- Replies: 2
- Views: 231
Re: Enthalpies of formation
Is it because it releases more energy to form bonds than it takes to break bonds? Resulting in a larger negative value?
- Wed Feb 19, 2020 7:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: midterm Q1A
- Replies: 7
- Views: 484
Re: midterm Q1A
Since it is an exothermkc reaction, heat is a product and therefore heating up the reaction would add product, shifting the reaction equilibrium to the left towards the reactants.
- Wed Feb 19, 2020 7:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 2
- Views: 195
Re: Salt Bridge
^^How does a salt bring deliver those charges? I can’t understand what a salt bridge physically is.
- Sat Feb 08, 2020 3:29 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Calculating bond enthalpies
- Replies: 4
- Views: 142
Re: Calculating bond enthalpies
Its on the practice midterm so I would study up on it. There is a really good example in the text book.
- Sat Feb 08, 2020 3:28 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Calculating bond enthalpies
- Replies: 4
- Views: 142
Re: Calculating bond enthalpies
Only multiply it by 3 if all three of the bonds are broken. IF two of the bonds are broken, then multiply that bond breakage by 2.
- Sat Feb 08, 2020 12:18 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 17
- Views: 1001
Re: Midterm
How similar will this practice test be to the actual midterm?
- Fri Feb 07, 2020 8:30 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Equations
- Replies: 3
- Views: 128
Re: Equations
I think the best way to remember them is to separate the equations into groups of categories\learning objectives and then by what is constant in the equations. The way they are separated in class notes make it easier so I would try making a study guide from that. rewriting the equations and when you...
- Fri Feb 07, 2020 8:26 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated vs Closed [ENDORSED]
- Replies: 34
- Views: 4303
Re: Isolated vs Closed [ENDORSED]
If the system doesn’t exchange energy(heat) or matter then it is isolated. If it exchanges Energy(heat) but not matter then it is closed. If it exchanges both then it is open.
An isolated water bottle doesn’t exchange heat with surroundings or matter so it is isolated.
An isolated water bottle doesn’t exchange heat with surroundings or matter so it is isolated.
- Fri Feb 07, 2020 8:25 pm
- Forum: Calculating Work of Expansion
- Topic: Units for Work
- Replies: 5
- Views: 273
Re: Units for Work
The SI units for pressure are Pascals and for V they are m^3. For work it is Joules so I think Pa times m^3 gives J.
- Sun Feb 02, 2020 6:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Variables
- Replies: 3
- Views: 143
Re: Variables
I was talking to a past student and they said that you should familiar yourself with the variables and equation sheet prior to the test. You will have a lot of equations in front of you but it’s important to know which equation and variables to use!
- Sun Feb 02, 2020 6:12 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter
- Replies: 5
- Views: 295
Re: Calorimeter
There are adiabatic calorimeters, oxygen bomb calorimeters, and differential scanning calorimeters (DSC). But in this class I’m pretty sure we focus on bomb calorimeters.
- Sun Feb 02, 2020 6:10 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A.13
- Replies: 3
- Views: 114
Re: 4A.13
I think because the temp change between temp in K and temp in C is the same?
- Sun Feb 02, 2020 6:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy of Rxn
- Replies: 9
- Views: 433
Re: Enthalpy of Rxn
Multiply. Also always look at the units for help. You need moles to cancel
- Sun Feb 02, 2020 6:07 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta U vs Delta H
- Replies: 4
- Views: 133
Delta U vs Delta H
What’s the difference between the delta U and delta H? How do I know when to use which one?
- Tue Jan 21, 2020 11:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Prepping for Test
- Replies: 6
- Views: 338
Re: Prepping for Test
I went to the test bank today to look for past exams but there were none! So I don;t suggest going there for help. 'Im going to stick with the homework problems and reviewing the learning outcomes.
- Tue Jan 21, 2020 11:13 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Week 3 hmwrk problems
- Replies: 2
- Views: 126
Re: Week 3 hmwrk problems
Yes. Homework problems should be from relevant and current lessons from lecture and section. And since we have a test on the first two topics in sections this week, homework should be from those two topics!
- Tue Jan 21, 2020 11:11 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximation
- Replies: 6
- Views: 251
Re: Approximation
It has to be smaller. Also check once you have your x value to make sure its less than 5% of the initial concentration,if it is then its a good approximation.
- Mon Jan 20, 2020 11:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6d.1
- Replies: 2
- Views: 156
Re: 6d.1
There is a table in the book. However sometimes you will need the Ka but you only have the KB for the conjugate and you’ll have to use (Ka)(Kb)=Kw relationship to solve for what you need.
- Mon Jan 20, 2020 11:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test One-
- Replies: 1
- Views: 164
Test One-
Will topic 6G be covered on test one? It’s not on the syllabus but we discussed buffers in class.
- Wed Jan 15, 2020 8:22 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Kw
- Replies: 16
- Views: 453
Re: Kw
Equilibrium constant and ionization constant of water are the same thing in this case.
- Wed Jan 15, 2020 8:20 am
- Forum: Administrative Questions and Class Announcements
- Topic: Study Guide Test One
- Replies: 17
- Views: 688
Study Guide Test One
Will there be a study guide given for test one? Or even just a practice test?
- Wed Jan 15, 2020 8:19 am
- Forum: Administrative Questions and Class Announcements
- Topic: Section 1D
- Replies: 1
- Views: 85
Section 1D
Was 1D’s section TA changed? My class is sitting in section that was supposed to start at 8am and no TA has shown up. It’s now 8:18. We don’t know what to do.
- Wed Jan 15, 2020 8:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What is K
- Replies: 6
- Views: 244
Re: What is K
I think of K as the blanket term for the equilibrium constant. Then more specifically we have Kc, Kp and Kw which are all slightly different but refer to the equilibrium constant as well.
- Wed Jan 15, 2020 8:12 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Hw for next week
- Replies: 19
- Views: 808
Re: Hw for next week
On the syllabus, it states that we can do any 5 questions from relevant and current topics. So since we just moved in to acids and bases on Monday I would say we can also do questions from equilibrium.
- Fri Jan 10, 2020 9:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Graphing K and Q Values
- Replies: 4
- Views: 187
Re: Graphing K and Q Values
In the textbook there is a small section describing graphs I believe. Not sure on the page numbers tho. So if it’s in the test it could possibly be tested. Maybe check the objectives and see if it’s there!
- Fri Jan 10, 2020 9:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Week 1 lecture note
- Replies: 4
- Views: 247
Re: Week 1 lecture note
Thank you! Will these be posted every week?
- Wed Jan 08, 2020 1:58 pm
- Forum: Ideal Gases
- Topic: Q and K
- Replies: 7
- Views: 289
Re: Q and K
K is used at equilibrium. Q can be used at any time during the reaction. You can find Q and then compare it to K. For instance is K=Q, then you know the reaction is at equilibrium.
- Wed Jan 08, 2020 1:56 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 413434
Re: Advice from a Medical Student [ENDORSED]
Coming into the chemistry 14 series was kinda scary for me, since I’ve never taken chemistry before. But after discovering chemistry community and posts like this, I’m very reassured that even if I struggle with the course it will be worth it in the long run(like when I eventually take the mcat). ju...
- Tue Jan 07, 2020 6:09 pm
- Forum: Ideal Gases
- Topic: Review Ideal Gases
- Replies: 6
- Views: 334
Re: Review Ideal Gases
Adding on to the previous answer with suggesting Khan Academy. They have great videos that flow in a logical and easy to remember way(for FREE). There is a whole section on ideal gases that includes review videos, mini quizzes and written text!