Search found 51 matches

by vibha gurunathan 1h
Sat Mar 14, 2020 5:40 pm
Forum: Ideal Gases
Topic: Weak vs Strong Acids and Bases
Replies: 3
Views: 14

Re: Weak vs Strong Acids and Bases

strong acids/bases dissociate completely; in contrast, weak acids/bases only partially dissociate, so you'd have to use the ka/kb value to figure out pH, concentration, etc.
by vibha gurunathan 1h
Sat Mar 14, 2020 5:39 pm
Forum: Student Social/Study Group
Topic: Coronavirus Joke
Replies: 14
Views: 143

Re: Coronavirus Joke

only good thing to come out of the coronavirus are memes like this
by vibha gurunathan 1h
Sat Mar 14, 2020 5:37 pm
Forum: Ideal Gases
Topic: Kc
Replies: 7
Views: 19

Re: Kc

for gases and aqueous substances you use concentrations
by vibha gurunathan 1h
Sat Mar 14, 2020 5:34 pm
Forum: Administrative Questions and Class Announcements
Topic: final exam - question
Replies: 6
Views: 76

final exam - question

sorry to ask this because I know Professor Lavelle's been working on the easiest/simplest way for us to take the final, but I was wondering whether we just submit the answers on the final exam? or do we have to write out the work on CCLE? If not, are we still able to get partial credit or is it all ...
by vibha gurunathan 1h
Fri Mar 13, 2020 9:03 pm
Forum: Administrative Questions and Class Announcements
Topic: take home FINAL DEADLINE
Replies: 15
Views: 212

Re: take home FINAL DEADLINE

I'm pretty sure it's going to be the same timeframe as the normal final.
by vibha gurunathan 1h
Fri Mar 13, 2020 7:22 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Identification
Replies: 4
Views: 23

Re: Identification

In addition to what everyone else said, it also includes certain elements that exist in their normal state in multiples (like P5)
by vibha gurunathan 1h
Fri Mar 13, 2020 6:31 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 8
Views: 26

Re: Arrhenius Equation

Sidharth D 1E wrote:To expand on that, reactions that give a straight line when lnkr is plotted against 1/T are said to show Arrhenius behavior


What is arrhenius behavior?
by vibha gurunathan 1h
Wed Mar 11, 2020 10:01 pm
Forum: Administrative Questions and Class Announcements
Topic: ENDGAME Review Session
Replies: 71
Views: 1811

Re: ENDGAME Review Session

Thanks so much Lyndon! Your review sessions and worksheets were incredibly helpful!
by vibha gurunathan 1h
Wed Mar 11, 2020 9:59 pm
Forum: Administrative Questions and Class Announcements
Topic: "Open Book" Final?
Replies: 30
Views: 324

Re: "Open Book" Final?

Do you know if chemistry community will be locked while we take the final?
by vibha gurunathan 1h
Wed Mar 11, 2020 9:58 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 22
Views: 256

Re: Final Exam

Diana Chavez-Carrillo 2L wrote:Does anyone know when we will be given our take-home final? Is it still going to be on Sunday?


I think it's still going to be sunday, as there's nothing to indicate otherwise
by vibha gurunathan 1h
Wed Mar 11, 2020 9:56 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 22
Views: 256

Re: Final Exam

Philip wrote:How are you guys going to be studying for the final


I'm planning to look over the study guide Dr. Lavelle sent out, do the endgame worksheet Lyndon posted, and review my notes/ do practice hw problems.
by vibha gurunathan 1h
Wed Mar 11, 2020 9:54 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 22
Views: 256

Re: Final Exam

Clara Cho 2K wrote:Do you think we will still meet for discussion?


I don't think so, I'm pretty sure we just email our hw in
by vibha gurunathan 1h
Wed Mar 11, 2020 9:53 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Activation Energy
Replies: 7
Views: 307

Re: Activation Energy

Catalysts create an alternate pathway - they speed up reactions by lowering Ea.
by vibha gurunathan 1h
Wed Mar 11, 2020 9:51 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: K vs k1/k'1
Replies: 6
Views: 318

Re: K vs k1/k'1

I'm pretty sure either work
by vibha gurunathan 1h
Wed Mar 11, 2020 9:47 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: What is 'A'?
Replies: 5
Views: 54

Re: What is 'A'?

In my notes, 'A' is defined as the frequency factor or pre-exponential factor (including # of collisions with correct orientation). What does this mean? Is this what we're trying to calculate with the Arrhenius equation? I'm pretty sure it's given. From what I remember in class, Dr. Lavelle said it...
by vibha gurunathan 1h
Wed Mar 11, 2020 9:34 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts and Reaction Pathways
Replies: 6
Views: 25

Re: Catalysts and Reaction Pathways

Besides adding a catalyst, can increasing the temperature, increasing pressure, or decreasing volume speed up a reaction with the large activation energy? I'd assume that it would change the reaction forwards/backwards in terms of Le Chatelier's Principle? but I'm honestly not too sure how it inter...
by vibha gurunathan 1h
Wed Mar 11, 2020 9:32 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Pre-Equilibrium Approach
Replies: 2
Views: 16

Re: Pre-Equilibrium Approach

The pre-equilibrium approach says that the intermediate is formed and sustained in a rapid formation reaction and its reverse, and you assume it reaches a sort of equilibrium. Instead, the steady state approach assumes that concentrations of the intermediates are low and don't change. As you don't w...
by vibha gurunathan 1h
Wed Mar 11, 2020 9:22 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Temperature and Reaction Rate
Replies: 6
Views: 19

Re: Temperature and Reaction Rate

K and temperature are proportional, so increasing temperature also increases k (increasing your rxn rate)
by vibha gurunathan 1h
Wed Mar 11, 2020 9:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 275
Views: 108564

Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle,

Thank you so much for all the work you put into teaching us this quarter! I really appreciate all the effort you put into lectures and organizing our review sessions, and I learned so much.
by vibha gurunathan 1h
Wed Mar 11, 2020 4:08 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: intermediate
Replies: 22
Views: 401

Re: intermediate

The intermediate is formed and used up, and it doesn't appear in the overall chemical equation
by vibha gurunathan 1h
Wed Mar 11, 2020 4:05 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Units for Thermo Calculations
Replies: 2
Views: 14

Re: Units for Thermo Calculations

I'm not completely sure, but I think Gibb's free energy is usually given in kJ/mol and delta H is given in J/mol. To be honest, though, I think either would work as long as it's the right one for the problem/right one with the information given
by vibha gurunathan 1h
Wed Mar 11, 2020 4:02 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Bottle Neck Effect
Replies: 4
Views: 30

Re: Bottle Neck Effect

005162520 wrote:Is the second step our first step and the second step or fast step?


I'm pretty sure it's when the second step is slow, so it limits how fast the first step can go
by vibha gurunathan 1h
Tue Mar 10, 2020 4:32 pm
Forum: Administrative Questions and Class Announcements
Topic: final
Replies: 6
Views: 58

Re: final

Rida Ismail 2E wrote:My guess is there will probably be an online alternative. I'm sure that Dr. Lavelle will send out an email in the next few hours about what he is going to do about finals.

Gotchu, thanks!!
by vibha gurunathan 1h
Tue Mar 10, 2020 4:15 pm
Forum: Administrative Questions and Class Announcements
Topic: final
Replies: 6
Views: 58

final

I know the news just broke, but does anyone know how the final is going to work?
by vibha gurunathan 1h
Tue Mar 10, 2020 3:04 pm
Forum: Second Order Reactions
Topic: determining order
Replies: 9
Views: 26

Re: determining order

You determine the order from experimental data - the method usually depends on the information given in the problem.
by vibha gurunathan 1h
Tue Mar 10, 2020 2:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 150
Views: 4892

Re: Advice from a Medical Student - Part II [ENDORSED]

Does anyone know when the best time to start preparing for the MCAT is? This is something that depends on each individual. Some people try to study while still taking classes. I took a gap year where I studied for the MCAT and did more clinical work. It's completely up to you. What's important to k...
by vibha gurunathan 1h
Tue Mar 10, 2020 2:55 pm
Forum: Administrative Questions and Class Announcements
Topic: ENDGAME Review Session
Replies: 71
Views: 1811

Re: ENDGAME Review Session

Thank you so much for creating this!!
by vibha gurunathan 1h
Mon Mar 09, 2020 2:09 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Study Advice
Replies: 73
Views: 3411

Re: Study Advice

KatrinaPho_2I wrote:If you look up the worksheets that the TA Joyce posts on chem community, they are really helpful. Lyndon's review sessions are also very helpful.


how do you look up the worksheets?
by vibha gurunathan 1h
Mon Mar 09, 2020 1:22 pm
Forum: General Science Questions
Topic: Who makes the Final
Replies: 23
Views: 109

Re: Who makes the Final

I'm pretty sure Professor Lavelle makes it.
by vibha gurunathan 1h
Thu Feb 27, 2020 12:15 pm
Forum: Balancing Redox Reactions
Topic: Oxygen's oxidation #
Replies: 6
Views: 43

Re: Oxygen's oxidation #

in addition to what everyone else said, elements in their standard state have an oxidation number of 0 (so like O2 would have an oxidation number of 0 or H2 would have an oxidation number of 0)
by vibha gurunathan 1h
Tue Feb 11, 2020 6:28 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: delta h and constant temp and pressure
Replies: 4
Views: 51

delta h and constant temp and pressure

How is delta H impacted when the system's at constant temperature and pressure?
by vibha gurunathan 1h
Sat Feb 08, 2020 11:07 am
Forum: Ideal Gases
Topic: Compressing a gas
Replies: 5
Views: 51

Compressing a gas

If a reaction is compressed, I know that it goes to the side with less molecules of gas, but I don't remember the explanation he used in class. Could someone explain that?
by vibha gurunathan 1h
Sat Feb 08, 2020 11:00 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 150
Views: 4892

Re: Advice from a Medical Student - Part II [ENDORSED]

Does anyone know when the best time to start preparing for the MCAT is?
by vibha gurunathan 1h
Sat Feb 08, 2020 10:49 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Addition of a solid product/reactant
Replies: 3
Views: 23

Addition of a solid product/reactant

If you add a solid product/reactant, does the reaction shift? (b/c it isn't in the K expression)
by vibha gurunathan 1h
Fri Feb 07, 2020 10:24 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy
Replies: 5
Views: 43

Re: Gibbs Free Energy

- if delta H is negative and delta S is positive, Gibbs Free energy is negative (spontaneous) - if delta H is positive and delta S is positive, T(delta S) has to be greater than delta H for Gibbs Free energy to be negative - if delta H is negative and delta S is negative, delta H has to be larger th...
by vibha gurunathan 1h
Fri Feb 07, 2020 9:56 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: state occupation of phases
Replies: 7
Views: 23

Re: state occupation of phases

Gases have their molecules a lot more spread out, liquids are only slightly spread out, and solids have their molecules tightly packed.
by vibha gurunathan 1h
Wed Jan 29, 2020 11:35 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Cpm and Cvm
Replies: 2
Views: 35

Cpm and Cvm

Why is Cpm (5/2)R and why is Cvm (3/2)R?
by vibha gurunathan 1h
Wed Jan 29, 2020 11:34 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4C.3
Replies: 3
Views: 66

Re: 4C.3

Ruby Tang 2J wrote:In the relevant section of the textbook, it is explained that for a monatomic ideal gas, Cp = 5/2R, while Cv = 3/2R, where R = 8.3145 J*K-1*mol-1.


Do you know if we'd need to know this on our test, or if they'd give us these values?
by vibha gurunathan 1h
Wed Jan 29, 2020 11:32 am
Forum: Ideal Gases
Topic: Inert Gas
Replies: 12
Views: 48

Re: Inert Gas

Inert gases don't react with any of the reactants or products.
by vibha gurunathan 1h
Wed Jan 29, 2020 11:31 am
Forum: Ideal Gases
Topic: Temperature
Replies: 17
Views: 97

Re: Temperature

It depends on the units of the constants in the problem. If it's a problem with molar heat capacity, use kelvin. If specific heat capacity, you would use celsius. Furthermore, usually you'd do delta T, which either would work. The ideal gas law, however, is always in kelvin, and usually if they ask ...
by vibha gurunathan 1h
Wed Jan 29, 2020 11:29 am
Forum: Ideal Gases
Topic: non ideal gases
Replies: 8
Views: 46

Re: non ideal gases

Increasing the amount of intermolecular forces causes more deviations from ideality, so gases that have a larger molar mass would be less ideal that gases with a lower molar mass. (E.g. CO2 would be less ideal than He)
by vibha gurunathan 1h
Wed Jan 29, 2020 11:26 am
Forum: Ideal Gases
Topic: ideal gases
Replies: 13
Views: 72

Re: ideal gases

Adding on to that, most gases are not "perfectly" ideal but they're close enough to the ideal. Gases with large volumes, a high pressure, or a very low temperature can cause deviations from this ideal.
by vibha gurunathan 1h
Sun Jan 26, 2020 6:59 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Aqueos and Gaseous Problems
Replies: 3
Views: 256

Re: Aqueos and Gaseous Problems

Use the concentration's (you can still use concentrations for gases).
by vibha gurunathan 1h
Sun Jan 26, 2020 6:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing K
Replies: 13
Views: 72

Re: Changing K

Only temperature can change K. (Pressure, volume, etc. can change the concentrations of reactants/products, but cannot change the equilibrium constant).
by vibha gurunathan 1h
Thu Jan 23, 2020 1:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb
Replies: 10
Views: 63

Re: Ka and Kb

Ka greater than 10^3 signifies a strong acid. Ka = [CB][H+]/ [HA] The more the acid (HA) dissociates, the more H+ is produced. This increases the Ka because the concentration of the products increases. If the Ka is greater than 10^3, that means it dissociates a lot, making it a strong acid and not a...
by vibha gurunathan 1h
Thu Jan 23, 2020 1:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H20 in the ICE table
Replies: 26
Views: 137

Re: H20 in the ICE table

Alexaaguilera wrote:I think you only include gases when doing an ICE


you include gases as well as aqueous reactants/products
by vibha gurunathan 1h
Thu Jan 23, 2020 12:29 pm
Forum: Ideal Gases
Topic: Inert Gases and Equilibrium
Replies: 6
Views: 44

Re: Inert Gases and Equilibrium

They don't react with either the reactants or products, so it does not shift equilibrium in either direction.
by vibha gurunathan 1h
Thu Jan 23, 2020 12:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B.3
Replies: 2
Views: 12

Re: 6B.3

I don't think there's a part c for 6B.3. Maybe it's a different problem that you're looking at?
by vibha gurunathan 1h
Sat Jan 18, 2020 1:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between K and Q?
Replies: 11
Views: 52

Re: Difference between K and Q?

The formula's the same and you find it in the same way, but you use current concentrations/pressures for Q and equilibrium concentrations/pressures for K.
by vibha gurunathan 1h
Thu Jan 09, 2020 5:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q
Replies: 2
Views: 29

Re: Q

It tells you relatively how much of the products or reactants are made. If Q is smaller than K, you don't have as many products made, so the reaction progresses forward to make more products to make Q larger and reach the value of K. If Q is larger than K, it will proceed in the direction of the rev...

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