Search found 16941 matches

by Chem_Mod
Sat Mar 16, 2019 4:20 pm
Forum: First Order Reactions
Topic: deriving integrated forms
Replies: 1
Views: 23

Re: deriving integrated forms

You most likely won't be asked to derive the integrated rate laws on the final exam.

Cheers! :)
by Chem_Mod
Sat Mar 16, 2019 4:13 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Test 1 problem 5
Replies: 6
Views: 65

Re: Test 1 problem 5

You'd do an ICE table with this reaction C3H5O2-(aq) + H20(l) --> C3H6O2(aq) + OH-(aq) You'd plug in the initial concentration of C3H5O2- to be 0.02 M and you'd solve for the Kb of C3H5O2- using Ka*Kb = 10^-14. Once you solve for x, x will be the [OH-]. Taking the negative log of [OH-] will give you...
by Chem_Mod
Sat Mar 16, 2019 4:06 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Law with Intermediates
Replies: 1
Views: 21

Re: Rate Law with Intermediates

Typically you can create a new rate constant which includes several k terms in it. For example, let's say you get rate = k 1 k 2 [OH-][KCl]/k -1 k -2 [PCl3], you can simplify this equation to being rate = k'[OH-][KCl]/[PCl3] if you write, "k' = k 1 k 2 /k -1 k -2 " Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:57 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Vant Hoff equation on formula sheet
Replies: 6
Views: 77

Re: Vant Hoff equation on formula sheet

The formula sheets can vary from exam to exam, so your best bet is to probably do enough problems with the Vant Hoff equation so it's very familiar to you for the next exam.

Cheers! :)
by Chem_Mod
Sat Mar 16, 2019 3:50 pm
Forum: Balancing Redox Reactions
Topic: multiplying half reactions [ENDORSED]
Replies: 4
Views: 26

Re: multiplying half reactions [ENDORSED]

You would not multiply the cell potential by that same factor. So for example, Ag+1 + e- -> Ag has a standard E value of 0.8 V.

If I were to multiply it by 3, giving me 3Ag+1 + 3e- -> 3Ag, this reaction would also have a standard E value of 0.8 V.

Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: standard cell potentials
Replies: 5
Views: 27

Re: standard cell potentials

Standard cell potentials do not have to be positive, but when a cell potential is positive, then, the delta G value is going to be negative which results in the cell reaction being spontaneous.

Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Porous Disk vs Salt Bridge
Replies: 2
Views: 13

Re: Porous Disk vs Salt Bridge

The porous disk and salt bridge essentially serve the same function. That being said, when using a porous disk, in the cell diagram, you would show the porous disk with one line "|" while you would show a salt bridge using 2 lines "||"

Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:38 pm
Forum: Balancing Redox Reactions
Topic: cell diagram
Replies: 3
Views: 26

Re: cell diagram

You would add Pt (s) when either the oxidation and/or reduction reaction does not have a pure metal solid in the reaction. So for example, if the oxidation reaction was Fe2+ -> Fe3+ + e-, then you would have to add Pt (s) on the left-most side of the cell diagram.

Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:33 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: e- transfer
Replies: 1
Views: 24

Re: e- transfer

By measuring the E (potential) for the anode and adding it to the E for the cathode, you will get the E for the redox reaction produced. The E for the anode and cathode can be measured by using a reference electrode such as the Standard Hydrogen Electrode (SHE). Typically, the E can be measured usin...
by Chem_Mod
Sat Mar 16, 2019 3:24 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Midterm Question 6
Replies: 6
Views: 51

Re: Midterm Question 6

Please, provide the full question when possible since we don't have full access to the midterms.

Thanks in advance! :)
by Chem_Mod
Sat Mar 16, 2019 3:18 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanisms without unknown rate-determining step
Replies: 2
Views: 21

Re: Reaction Mechanisms without unknown rate-determining step

If a mechanism is provided, but there isn't enough information given to figure out which step is slow and which step(s) are fast, then there isn't enough information to be able to solve for the rate law of this reaction mechanism.

Hope this helps! :)
by Chem_Mod
Sat Mar 16, 2019 3:13 pm
Forum: First Order Reactions
Topic: half life
Replies: 3
Views: 24

Re: half life

The half-life equations are derived using the integrated rate law formulas by setting the final concentration equal to half the initial concentration and solving for time (t). When deriving the half-life equation for the 1st order reactions, the initial concentration terms will cancel out. However, ...
by Chem_Mod
Sat Mar 16, 2019 3:06 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst equation
Replies: 1
Views: 14

Re: Nernst equation

Eo are the standard reduction potential values that are typically given as constants. At equilibrium E is = 0 because there is no net transfer of electrons, which is how you go from the first equation to the second.
by Chem_Mod
Sat Mar 16, 2019 3:05 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: delta s
Replies: 2
Views: 19

Re: delta s

When delta S total is positive, the process is spontaneous. This means that if the delta S total is negative, then the process is not spontaneous. When bonds are formed, the delta S total is typically negative since forming bonds usually decreases the amount of disorder (entropy) overall. This is be...
by Chem_Mod
Sat Mar 16, 2019 2:59 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Question 15.79 (Sixth Edition)
Replies: 1
Views: 19

Re: Question 15.79 (Sixth Edition)

If the product that is formed due to the faster reaction is under kinetic control then that is the reaction with a lower activation energy. We know this because lower activation energy means higher reaction rate. Kinetic control predominates at lower temperature because due to the lack of sufficient...
by Chem_Mod
Sat Mar 16, 2019 2:50 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.3c, 6th edition
Replies: 1
Views: 11

Re: 14.3c, 6th edition

The products are H+1 and Cl-1 because we know that HCl dissolves in an aqueous solution. To answer your second question, you add a solid such as Pt when there is no solid present to facilitation the transfer of electrons.
by Chem_Mod
Sat Mar 16, 2019 2:49 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Week 10 Discussion Notes (2E,2I,2K)
Replies: 6
Views: 225

Re: Week 10 Discussion Notes (2E,2I,2K)

Hi, does anyone know why delta H was 300 and not -300 when calculating the reverse activation energy? Didn't they give it as -300, and it's an exothermic reaction so deltaH should be negative? For the reverse reaction, new delta H = - delta H. The forward reaction is exothermic and delta H = -300, ...
by Chem_Mod
Sat Mar 16, 2019 2:48 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: justified approximation
Replies: 1
Views: 26

Re: justified approximation

I am not sure what you are referring to when you say second ionization but if you are referring to the second ionization for a diprotic or polyprotic acid we can, for the most part, ignore it because the amount of hydronium (H +1 ) produced from the first deprotonation is significantly greater than ...
by Chem_Mod
Sat Mar 16, 2019 2:41 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Reducing Power and Oxidation Power
Replies: 1
Views: 17

Re: Reducing Power and Oxidation Power

Reducing power is the ability of a substance to reduce another substance. Therefore, in order for something to have high reducing power it itself must easily be oxidized. Thus, the relationship is as reducing power increases, reduction potential (desire to gain electrons) decreases. Oxidizing power ...
by Chem_Mod
Sat Mar 16, 2019 2:39 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Homogenous/Heterogeneous Catalysts
Replies: 2
Views: 25

Re: Homogenous/Heterogeneous Catalysts

In terms of the difference between the two, understand that a homogenous catalyst is more effective because it mixes much better with your reactants. This makes sense if you think about liquid reactants mixing with a liquid catalyst as opposed to liquid reactants interacting with a solid catalyst. T...
by Chem_Mod
Sat Mar 16, 2019 2:36 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 7th Edition 7D.5
Replies: 3
Views: 39

Re: 7th Edition 7D.5

Please post the entire problem.
by Chem_Mod
Sat Mar 16, 2019 2:35 pm
Forum: First Order Reactions
Topic: ln
Replies: 1
Views: 15

Re: ln

No, taking the natural log of a number with units will lead to an answer without units.
by Chem_Mod
Sat Mar 16, 2019 2:33 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Homework 7E3
Replies: 1
Views: 19

Re: Homework 7E3

Please post the entire problem
by Chem_Mod
Sat Mar 16, 2019 2:32 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N.3c Cell Potential
Replies: 1
Views: 9

Re: 6N.3c Cell Potential

The left side of this cell notation is the anode and the right side is the cathode. This applies for all cell notations.
by Chem_Mod
Sat Mar 16, 2019 2:30 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: K
Replies: 1
Views: 13

Re: K

K represents the equilibrium constant
by Chem_Mod
Sat Mar 16, 2019 2:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35
Replies: 3
Views: 46

Re: 5.35

So the reason why they divide by 100 is to convert kPa into atm. We do this because atm is the standard unit when calculating Kp, and if we used kPa, it would deviate from the expected answer.
by Chem_Mod
Sat Mar 16, 2019 1:14 pm
Forum: Ideal Gases
Topic: Bar for partial pressure [ENDORSED]
Replies: 4
Views: 38

Re: Bar for partial pressure [ENDORSED]

Yes, bar is the standard unit for partial pressure in K calculation
by Chem_Mod
Sat Mar 16, 2019 12:41 pm
Forum: Administrative Questions and Class Announcements
Topic: LYNDON'S PORK RAMEN REVIEW
Replies: 37
Views: 1692

Re: LYNDON'S PORK RAMEN REVIEW

I do not have an answer key made to be able to post anything. In addition, many of the questions involve drawing or explaining and I unfortunately do not have the time to make an adequate postable key. During my session, I will ask for some neat note-takers to post their notes here though.
by Chem_Mod
Sat Mar 16, 2019 12:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Problem 11.27 (sixth edition)
Replies: 1
Views: 14

Re: Problem 11.27 (sixth edition)

The equilibrium constant K which is 25 = Partial Pressure of Products /Partial Pressure of reactants. Therefore,
25 = ( PPCL3 PCl2 )/ PPCl5

You can then plug in the values that you have and solve for the partial pressure of PCl3.
by Chem_Mod
Sat Mar 16, 2019 12:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: HW problem 15.67
Replies: 1
Views: 21

Re: HW problem 15.67

In order to answer this question you have to set a ratio for the Arrhenius Equations and solve for the ratio of the rate constants. You then realize that by whatever factor the rate constants changed is the factor by which the rates changed because there is a linear relationship between the two give...
by Chem_Mod
Sat Mar 16, 2019 12:08 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: HW problem 15.73
Replies: 1
Views: 14

Re: HW problem 15.73

Within the individual steps it may appear that the catalyst is being consumed, however this question is trying to get at the fact that in the course of the overall reaction a catalyst is not consumed, which is true.
by Chem_Mod
Sat Mar 16, 2019 12:06 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Coefficients for the rate of reaction
Replies: 1
Views: 27

Re: Coefficients for the rate of reaction

You can only do this for an elementary reaction because that is the only step that leads to your products. With other reactions, the overall reaction often times contains multi-step mechanisms that are not shown, therefore the rate would be dependent only on the slow step of the mechanism.
by Chem_Mod
Sat Mar 16, 2019 11:59 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Combustion
Replies: 1
Views: 13

Re: Combustion

The spontaneity of combustion reactions can be understood by looking at the entropy and enthalpy of the system. Combustion reaction have a negative enthalpy change because heat is released in going from reactants to products. That coupled with the fact that entropy change is almost always positive l...
by Chem_Mod
Sat Mar 16, 2019 11:52 am
Forum: First Order Reactions
Topic: Using Plots to determine order
Replies: 1
Views: 15

Re: Using Plots to determine order

You do not need to worry about something like that, just know that a zeroth order reaction has a negative slope of [A] vs t,
first order has a negative slope of ln[A] vs t, and second order has a positive slope of 1/[A] vs t.
by Chem_Mod
Sat Mar 16, 2019 11:49 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Nernst Equation
Replies: 2
Views: 15

Re: Nernst Equation

These are essentially the same thing. The 0.05916 is the constant that you get when you calculate RT/F.
by Chem_Mod
Sat Mar 16, 2019 1:32 am
Forum: Student Social/Study Group
Topic: Studying for the Final
Replies: 25
Views: 269

Re: Studying for the Final

viewtopic.php?f=160&t=44659

For material after the midterm
by Chem_Mod
Sat Mar 16, 2019 1:30 am
Forum: Student Social/Study Group
Topic: Lyndon's Review Session
Replies: 8
Views: 231

Re: Lyndon's Review Session

viewtopic.php?f=160&t=44659

For material after the midterm
by Chem_Mod
Fri Mar 15, 2019 11:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law Problem (8.55 in the Sixth Edition)
Replies: 2
Views: 31

Re: Hess's Law Problem (8.55 in the Sixth Edition)

The second reaction in the question is not balanced, the 3/2 is used to balance the reaction.
by Chem_Mod
Fri Mar 15, 2019 11:29 pm
Forum: Second Order Reactions
Topic: Half-life of Second-Order
Replies: 1
Views: 36

Re: Half-life of Second-Order

I am not sure what that means but you definitely want to know the expression of half-lives for both 0th 1st and 2nd order reactions.
by Chem_Mod
Fri Mar 15, 2019 11:12 pm
Forum: Student Social/Study Group
Topic: Michelle Nguyen Photos
Replies: 1
Views: 55

Re: Michelle Nguyen Photos

These are great Katelin.
Thank you!
by Chem_Mod
Fri Mar 15, 2019 10:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.9) 7th edition [ENDORSED]
Replies: 1
Views: 97

Re: 4D.9) 7th edition [ENDORSED]

Super long day.

Nothing has a negative density.

The equivalent would be a negative density for water.

-1g/ml it makes no sense.

Similary, there is no negative energy per gram.

Thank you for all the good wishes, hugs, cards, photos, and smiles.

Wishing you all the Best with your finals.
by Chem_Mod
Fri Mar 15, 2019 7:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Practice Problem
Replies: 3
Views: 76

Re: Final Exam Practice Problem

Here are the answer keys!

Week 10-1 Workshop Key.docx
(523.29 KiB) Downloaded 29 times

Week 10-2 Workshop Key.docx
(3.66 MiB) Downloaded 36 times
by Chem_Mod
Fri Mar 15, 2019 7:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Practice Problem
Replies: 3
Views: 76

Final Exam Practice Problem

Hello Everyone!

Here are my worksheets from my sessions during week 10. They contain questions from most of the chapters that we went through this quarter. Let me know if you have any questions. Good luck studying!

Week 10-1 Workshop.docx
(126.76 KiB) Downloaded 36 times

Week 10-2 Workshop.docx
(2.05 MiB) Downloaded 27 times


Best Wishes,
Cindy Chen
by Chem_Mod
Fri Mar 15, 2019 7:07 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 7th edition 6N.1
Replies: 1
Views: 13

Re: 7th edition 6N.1

I am not sure about other calculation but the n should be 2 because there are two moles of electron transfer.
by Chem_Mod
Fri Mar 15, 2019 6:14 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: modeling enthalpy
Replies: 1
Views: 46

Re: modeling enthalpy

Do you mean the enthalpies of formation of each species or the enthalpies of reaction or the enthalpies of activation? The enthalpy of reaction for one step corresponds to the vertical distance between reactant and the product of that step (either of which could actually be intermediates). Positive ...
by Chem_Mod
Fri Mar 15, 2019 4:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework #115 Ch.8 Ed.6
Replies: 1
Views: 30

Re: Homework #115 Ch.8 Ed.6

dN = N final - N initial. This is a state function.
by Chem_Mod
Fri Mar 15, 2019 4:35 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: problem 7E3
Replies: 1
Views: 23

Re: problem 7E3

Please show us the problem and show your work so we can see where you are struggling and better assist you.
by Chem_Mod
Fri Mar 15, 2019 4:34 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Homework help
Replies: 1
Views: 36

Re: Homework help

Please show us the problem and your work so we can better assist you.
by Chem_Mod
Fri Mar 15, 2019 4:34 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Problem 61 6th Edition
Replies: 1
Views: 21

Re: Problem 61 6th Edition

Please post the question on this platform so that we do not need to reference back to the textbook. Also, which chapter is question 61 refering to.
by Chem_Mod
Fri Mar 15, 2019 4:34 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Homework 6N17
Replies: 1
Views: 22

Re: Homework 6N17

If Q is less than one than one, than there is a drive (energy to be released) to make more products. Please show us the problem so we know exactly where you are struggling and better assist you.
by Chem_Mod
Fri Mar 15, 2019 4:31 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Homework 6N13a
Replies: 1
Views: 21

Re: Homework 6N13a

Please show us the problem so we don't have to reference the text book on this platform.
by Chem_Mod
Fri Mar 15, 2019 4:30 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: problem 6N5a and b
Replies: 1
Views: 26

Re: problem 6N5a and b

Please show us the problem so we don't have to reference the text book on this platform and show your work so we know where you may struggle.
by Chem_Mod
Fri Mar 15, 2019 4:28 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 7th 6.65
Replies: 2
Views: 33

Re: 7th 6.65

Please attempt the problem, show us your work, so we can gage where you may be struggling with it.
by Chem_Mod
Fri Mar 15, 2019 4:26 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Kinetic Energy
Replies: 1
Views: 37

Re: Kinetic Energy

Hint: Is the rate-determining step the fastest or the slowest step?
by Chem_Mod
Fri Mar 15, 2019 4:25 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: homework question
Replies: 1
Views: 32

Re: homework question

Please thoroughly show your work so students do not have to reference the text book.
by Chem_Mod
Fri Mar 15, 2019 4:23 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: solutions manual error?
Replies: 1
Views: 29

Re: solutions manual error?

Please thoroughly show your work so students don't have to reference the text books.
by Chem_Mod
Fri Mar 15, 2019 4:23 pm
Forum: General Rate Laws
Topic: Q 15.29 6th edition
Replies: 1
Views: 22

Re: Q 15.29 6th edition

I have attached a detailed worked out solution. Hope this helps.
by Chem_Mod
Fri Mar 15, 2019 3:54 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6th ed 14.55
Replies: 1
Views: 39

Re: 6th ed 14.55

We have are Ni^(2+), SO4^ (2-), and H2O. Oxidation: 0.5 O2 + 2H + +2e - --> H2O E=0.82 Reduction: SO4 2- + 4H + + 4e - --> H2SO3 + H2O E=0.17 Ni 2+ + 2e - --> Ni E=-0.26 2H2O + 2e - --> H2 + 2OH - E=-0.41 I believe SO4 2- is not included because the solution is neutral Anode: H 2 O --> 0.5O 2 + 2H +...
by Chem_Mod
Fri Mar 15, 2019 3:39 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 7E5 Intermediates
Replies: 1
Views: 20

Re: 7E5 Intermediates

An intermediate is formed and then consumed. It does NOT show up in the net equation. On the other hand, an enzyme is present at the beginning and end of a reaction. By the Induced Fit Theory, an enzyme changes its conformation slightly during the reaction, but is unchanged after. Enzymes are regene...
by Chem_Mod
Fri Mar 15, 2019 3:04 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Week 10 Discussion Notes (2E,2I,2K)
Replies: 6
Views: 225

Week 10 Discussion Notes (2E,2I,2K)

Dear all,

Attached please find the worksheet answer key and discussion notes.

Good luck on your finals! ٩(๑>◡<๑)۶

Best,
Joyce
by Chem_Mod
Fri Mar 15, 2019 2:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Yekan Final review slides and solutions 0312
Replies: 8
Views: 206

Re: Yekan Final review slides and solutions 0312

Christine Chen 1H wrote:How do you find the number of moles and V2, V1 for this problem?

Number of moles are from dividing the mass by the molar mass. V2 is the final volume after mixing, which is the sum of volume of the two sides, and V1 is the initial volume which is given for each part (7.6L and 5.3L).
by Chem_Mod
Fri Mar 15, 2019 12:39 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Number 7.31 7th Edition
Replies: 1
Views: 25

Re: Number 7.31 7th Edition

They omit the negative sign in front of the Ea/R so the order of 1/T is flipped.
by Chem_Mod
Fri Mar 15, 2019 12:34 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2, Number 6 part b
Replies: 1
Views: 34

Re: Test 2, Number 6 part b

Yes. The more positive, the stronger the oxidation power.
by Chem_Mod
Fri Mar 15, 2019 7:21 am
Forum: Administrative Questions and Class Announcements
Topic: LAST LECTURE
Replies: 1
Views: 24

Re: LAST LECTURE

Yes that is what I said.
by Chem_Mod
Fri Mar 15, 2019 6:41 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Review Session-Thermo-files- Wednesday-Q11-clarification [ENDORSED]
Replies: 10
Views: 257

Re: Review Session-Thermo-files- Wednesday-Q11-clarification [ENDORSED]

You don’t have to necessarily be given a diagram. But it has to be stated in words that it is a constant pressure process while changing T.
by Chem_Mod
Fri Mar 15, 2019 4:51 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: homework
Replies: 1
Views: 32

Re: homework

You will have the Arrhenius equations for the two temperatures and subtract the two. So, at T1: lnk_{1} = ln A - \frac{E_{a}}{RT_{1}} and at T2: lnk_{2} = ln A - \frac{E_{a}}{RT_{2}} . lnA is eliminated when we subtract the two equations and we get lnk_{2} - lnk_{1} =- \frac{E_{a}}{RT_{2}} + \frac{E...
by Chem_Mod
Fri Mar 15, 2019 4:50 am
Forum: General Rate Laws
Topic: Sealed vessel
Replies: 1
Views: 26

Re: Sealed vessel

According to the solutions manual, since the vessel is sealed the masses and concrentartions are proportional. Therefore, any change in mass, causes a proportional change in concentration. So it is uneccesary to take the extra steps and convert the masses to moles and then concentrations when you ca...
by Chem_Mod
Fri Mar 15, 2019 4:49 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calomel electrode
Replies: 1
Views: 24

Re: Calomel electrode

Calomel electrodes are beyond the scope of this class. What's more important is distinguishing between anodes and cathodes within various types of cells like galvanic or electrolytic.
by Chem_Mod
Fri Mar 15, 2019 4:48 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35
Replies: 3
Views: 46

Re: 5.35

Please post the entire question.
by Chem_Mod
Fri Mar 15, 2019 4:47 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 7D.5
Replies: 1
Views: 25

Re: 7D.5

You will have the Arrhenius equations for the two temperatures and subtract the two. So, at T1: lnk_{1} = ln A - \frac{E_{a}}{RT_{1}} and at T2: lnk_{2} = ln A - \frac{E_{a}}{RT_{2}} . lnA is eliminated when we subtract the two equations and we get lnk_{2} - lnk_{1} =- \frac{E_{a}}{RT_{2}} + \frac{E...
by Chem_Mod
Fri Mar 15, 2019 3:35 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: HW 5I.33 7th edition
Replies: 1
Views: 20

Re: HW 5I.33 7th edition

Please post the entire question.
by Chem_Mod
Fri Mar 15, 2019 1:43 am
Forum: Administrative Questions and Class Announcements
Topic: LYNDON'S PORK RAMEN REVIEW
Replies: 37
Views: 1692

LYNDON'S PORK RAMEN REVIEW

The title is called "Pork Ramen" so that you can search "Pork Ramen" and easily find this post! This is your UA, Lyndon Bui, with information on the much anticipated Pork Ramen Review Session! This review session will feature a second lovely UA, Hannah Chew! This packet covers m...
by Chem_Mod
Thu Mar 14, 2019 11:23 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pseudo 1st order reaction
Replies: 2
Views: 42

Re: Pseudo 1st order reaction

We use pseudo first order reactions when we are studying a reaction with multiple reactants with concentrations that could affect the rate law. For example if the reaction in question is A+B-->P we would design an experiment to find out how the rate changes with the concentrations of each reactant. ...
by Chem_Mod
Thu Mar 14, 2019 11:18 pm
Forum: *Enzyme Kinetics
Topic: Do we need to know enzyme kinetics for the final?
Replies: 1
Views: 34

Re: Do we need to know enzyme kinetics for the final?

Kinetics is fair game.
by Chem_Mod
Thu Mar 14, 2019 11:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Bronsted Neutralization Reaction
Replies: 1
Views: 24

Re: Bronsted Neutralization Reaction

Notice the number of electrons for each set of reactions. This becomes important when calculating deltaGo, since it equals nFEocell. Voltage is an intrinsic property, so as long as the identify of the reaction is the same, the voltage/potential should be the same.
by Chem_Mod
Thu Mar 14, 2019 11:03 pm
Forum: First Order Reactions
Topic: Linear Plots
Replies: 1
Views: 27

Re: Linear Plots

Well, rate would equal k[A]. In this case, k would be the slope, and rate with respect to [A] would be linear.
by Chem_Mod
Thu Mar 14, 2019 10:59 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: given Ecell
Replies: 2
Views: 44

Re: given Ecell

You can think of it that way, but normally the progression of thought is that galvanic/voltaic cells are spontaneous with positive Ecell, whereas electrolytic cells are nonspontaneous with negative Ecell.
by Chem_Mod
Thu Mar 14, 2019 10:57 pm
Forum: General Rate Laws
Topic: Determining rate order
Replies: 3
Views: 27

Re: Determining rate order

You determine the order of one reactant each time so you want to pick the experiments where the only variation is the concentration of the reactant you are studying.
by Chem_Mod
Thu Mar 14, 2019 10:52 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energy v. Free Energy of Activation
Replies: 1
Views: 23

Re: Activation Energy v. Free Energy of Activation

It is probably beyond the scope of this class. Free energy of activation contains an entropic term in addition to the enthalpic one. On the other hand, the activation energy doesn't, entropic part is accounted for by the pre-exponential factor A.
by Chem_Mod
Thu Mar 14, 2019 10:46 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 15.67 6th Edition (Catalyst)
Replies: 1
Views: 23

Re: 15.67 6th Edition (Catalyst)

The idea is that you want to calculate the ratio of the rate constant k. You can use two Arrhenius equations and take the ratio or the solution manual used the law of log which also works
by Chem_Mod
Thu Mar 14, 2019 10:44 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Hmwrk 15.65
Replies: 1
Views: 19

Re: Hmwrk 15.65

To figure out (b), you have to compare the activation energies for the forward and reverse reactions. Exothermic reactions have a larger activation energy for the reverse reaction, whereas endothermic reactions have a larger activation energy for the forward reaction. You then can use this informati...
by Chem_Mod
Thu Mar 14, 2019 10:42 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: k’ and A
Replies: 4
Views: 36

Re: k’ and A

k is the rate constant and A is the collision factor
by Chem_Mod
Thu Mar 14, 2019 10:40 pm
Forum: General Rate Laws
Topic: Questions with different Experiments
Replies: 1
Views: 14

Re: Questions with different Experiments

The reason to run different experiments is to figure out the order with respect to each reactant. After you figure out all the orders, you can plug in data from any experiment to figure out the rate constant k.
by Chem_Mod
Thu Mar 14, 2019 10:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Conductivity
Replies: 1
Views: 18

Re: Conductivity

Generally, all the metals are good conductors.
by Chem_Mod
Thu Mar 14, 2019 10:37 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Entropy for irreversible reaction
Replies: 1
Views: 21

Re: Entropy for irreversible reaction

I think you are talking about irreversible free expansion, because it is free expansion, there is no heat transfer.
by Chem_Mod
Thu Mar 14, 2019 10:35 pm
Forum: First Order Reactions
Topic: integrated rate laws
Replies: 3
Views: 23

Re: integrated rate laws

Both of them should work, but usually, the ln one is more convenient in term of doing calculation
by Chem_Mod
Thu Mar 14, 2019 10:24 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: C in a diatomic molecule
Replies: 3
Views: 31

Re: C in a diatomic molecule

Cv is 5/2 R, whereas Cp is 7/2R. Cp = Cv + R always.
by Chem_Mod
Thu Mar 14, 2019 10:21 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst vs intermediate
Replies: 9
Views: 45

Re: catalyst vs intermediate

A catalyst is used up and regenerated. An intermediate is formed and used up.
by Chem_Mod
Thu Mar 14, 2019 9:19 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanisms
Replies: 2
Views: 35

Re: Reaction Mechanisms

Please give an example of what you saw. Usually, reaction mechanisms are not used to judge if a reaction is endo or exothermic
by Chem_Mod
Thu Mar 14, 2019 9:17 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: DeltaG dependence on equilibrium constant and pressure
Replies: 1
Views: 28

Re: DeltaG dependence on equilibrium constant and pressure

Delta G = -RTlnK, this equation shows the relationship between equilibrium constant and the Gibbs free energy. Meanwhile, the K can bewrite in terms of partial pressure if gases are involved in your reaction.
by Chem_Mod
Thu Mar 14, 2019 8:28 pm
Forum: General Rate Laws
Topic: when to use what
Replies: 1
Views: 22

Re: when to use what

average rate: over some period of time (ex: rate from 30s to 60s)
instantaneous rate: at a specific point in time (Ex: rate at 1s)
"non unique" rate: what is the rate with respect to x reactant or x product
Unique rate: will usually specify
by Chem_Mod
Thu Mar 14, 2019 8:22 pm
Forum: General Rate Laws
Topic: 15.19 6th edition
Replies: 4
Views: 23

Re: 15.19 6th edition

It would help to post your work to see where the error is!
by Chem_Mod
Thu Mar 14, 2019 8:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Pseudo Equlibrium
Replies: 2
Views: 18

Re: Pseudo Equlibrium

Be prepared to answer any questions related to lecture notes or homework.
by Chem_Mod
Thu Mar 14, 2019 8:18 pm
Forum: General Rate Laws
Topic: Unique, Instantaneous, and Average Rate
Replies: 1
Views: 19

Re: Unique, Instantaneous, and Average Rate

Instantaneous rate is exactly what it sounds like: at a specific point in time, what is the rate? Average rate, on the other hand: what is the rate over a given period of time? Keep in mind that this is less accurate than instantaneous rate. At each point in time, the rate varies, so taking an avera...

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