Search found 57 matches

Wed Mar 11, 2020 3:32 pm
Forum: General Rate Laws
Topic: Rate limiting step
Replies: 13
Views: 127

Re: Rate limiting step

how would u determine which elementary step is the limiting?
Tue Mar 10, 2020 9:06 pm
Forum: Student Social/Study Group
Topic: Lyndon Review
Replies: 6
Views: 259

Re: Lyndon Review

Angela Prince 1J wrote:did lyndon already put up the worksheet?

yes search for "endgame"
Tue Mar 10, 2020 9:04 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Coming up with Reaction steps
Replies: 2
Views: 53

Re: Coming up with Reaction steps

Deepika Reddy 1A wrote:You would never have to come up with the reaction mechanism. You would just have to interpret them or see if with the information you have you can prove the reaction mechanism is correct or wrong.

can you briefly explain how we would do that?
Tue Mar 10, 2020 5:44 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: reaction mechanism
Replies: 2
Views: 25

reaction mechanism

do we need to know how to find the elementary steps given an overall reaction?
Tue Mar 10, 2020 4:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Worksheet for Review Session?
Replies: 3
Views: 127

Re: Worksheet for Review Session?

i'm not sure there is since I have also been on the lookout but haven't come across any.
Mon Mar 09, 2020 8:47 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Quick inquiry about enzyme catalysis
Replies: 1
Views: 30

Re: Quick inquiry about enzyme catalysis

Brian_Ho_2B wrote:Do we have to know anything about the equation: Rate of Product formation = k2[E]o[S]/(Km + [S]) and do we need to know anything about Km = (k1' + k2)/k1 ?

I was wondering the same thing because they aren't on the equation sheet? would we need to know its implications instead?
Mon Mar 09, 2020 8:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What do we do when we are faced with a cubic equation?
Replies: 2
Views: 24

Re: What do we do when we are faced with a cubic equation?

if I remember correctly, when he discussed ice tables he also mentioned that he wouldn't give us a scenario involving cubic equations. if it came down to it, you would need to remember that if the K value is less than 5%, you can get rid of the x In addition or subtraction to make it a quadratic. I ...
Sun Mar 08, 2020 7:05 pm
Forum: Student Social/Study Group
Topic: 03/06 Lecture
Replies: 2
Views: 96

Re: 03/06 Lecture

Deena Doan 2F wrote:I can. What's your email?

thank you so much! it's dinamelkonian@gmail.com
Sat Mar 07, 2020 4:10 pm
Forum: Student Social/Study Group
Topic: 03/06 Lecture
Replies: 2
Views: 96

03/06 Lecture

Hello! can someone please share the lecture notes from Friday's class? thank you
Thu Mar 05, 2020 10:23 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Electromotive force (emf)
Replies: 9
Views: 104

Re: Electromotive force (emf)

the book mentions that EMF is the same as the cell potential of a cell.
Thu Mar 05, 2020 7:55 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: max work and cell potential
Replies: 3
Views: 61

max work and cell potential

I know that max work= -nFE but where does that comes from or what is the logic behind it/ what does it signify?
Wed Mar 04, 2020 6:36 pm
Forum: Balancing Redox Reactions
Topic: Homework Problem 6K.1
Replies: 3
Views: 58

Re: Homework Problem 6K.1

the balanced reduction reaction is missing a 6e- on the left side in order to balance the charges. so the oxidation reaction is multiplied by 3 so that the 2e- can balance with the 6e- from the reduction So for the final balanced redox reaction, we just have to make sure that the electrons cancel o...
Tue Mar 03, 2020 2:56 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating Q
Replies: 3
Views: 52

Re: Calculating Q

for a concentration cell, the side with the lower concentration is the anode. My TA mentioned that in that case, Q=anode/cathode, which is the same as lower concentration/higher concentration.
Sun Mar 01, 2020 5:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating Q
Replies: 3
Views: 52

Re: Calculating Q

You find Q the same we did in chemical equilibria however, now the chemical equation will be the balanced redox reactions. A concentration cell is when a galvanic or voltaic cell is made using the same components but at different concentrations. if the Ecell has the same solution of cathode and anod...
Sun Mar 01, 2020 5:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 62

Re: Cell Diagrams

I don't think they would make us draw out the galvanic cell diagrams but they might test us on the understanding of writing out the cell diagram, ie:
Al(s) | Al3+(aq) || Sn2+(aq) | Sn(s)
Sun Mar 01, 2020 5:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating E°cell
Replies: 2
Views: 38

Re: Calculating E°cell

E°cell= E°cathode − E°anode is used when the half reactions are both in reduction form so ie: Cu ^2+ + 2e -> Cu. E°cell= E°cathode + E°anode is used when the half reaction of the anode is in its real state, oxidized, ie: Cu -> Cu^2+ + 2e. if done right, both ways give you the same answer.
Thu Feb 27, 2020 5:40 pm
Forum: Administrative Questions and Class Announcements
Topic: UA sessions
Replies: 5
Views: 54

UA sessions

if we go to sessions during week 9, will they be going over week 9 material or can we still get help with electrochemistry?
Thu Feb 27, 2020 5:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Common Solutions in Salt Bridges
Replies: 2
Views: 26

Re: Common Solutions in Salt Bridges

A salt bridge is a non-covalent interaction between two ionized sites. It has two components: a hydrogen bond and an electrostatic interaction. it provides negative ions to excess positive charge and positive ions to excess negative charge. A common one is KCL/KNO3.
Thu Feb 27, 2020 5:33 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Standard electron potential
Replies: 2
Views: 22

Standard electron potential

how does the standard electrode potential value tell us its ability to act as a reducing or oxidizing agent?
Tue Feb 25, 2020 11:04 am
Forum: Balancing Redox Reactions
Topic: reducing agent
Replies: 5
Views: 64

Re: reducing agent

"Reducing agent is an element or compound that loses an electron to an electron recipient in a redox chemical reaction. A reducing agent is thus oxidized when it loses electrons in the redox reaction."
Mon Feb 24, 2020 2:42 pm
Forum: Student Social/Study Group
Topic: 2/24 lecture
Replies: 5
Views: 67

2/24 lecture

I wasn't able to make it to lecture today, so can anyone give me a brief synopsis of the class from today? Thank you!
Thu Feb 20, 2020 7:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reaction A
Replies: 1
Views: 31

Re: Reaction A

The Daniell cell is an early example of a galvanic cell that makes use of the oxidation of copper by zinc ions, as in reaction A. this can be found in 6L.1, I'm pretty sure this is the first time Reaction A has been used.
Thu Feb 20, 2020 7:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 8
Views: 52

Re: Galvanic Cells

Galvanic cells harness the electrical energy available from the electron transfer in a redox reaction to perform useful electrical work. The key to gathering the electron flow is to separate the oxidation and reduction half-reactions. "Galvanic cells are very important to our lives because they...
Thu Feb 20, 2020 5:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard reduction potential
Replies: 2
Views: 46

Re: Standard reduction potential

the professor mentioned how the standard reduction potential says the same throughout balancing half reactions. only the sign changes if the half reaction has to be reversed.
Thu Feb 20, 2020 5:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: calculating E(cell)
Replies: 2
Views: 20

calculating E(cell)

in class, we went over two different ways in finding the standard reduction potential. both ways gave the same answer so which is the preferred method?
Thu Feb 20, 2020 5:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Extensive and Intensive Properties
Replies: 12
Views: 232

Re: Extensive and Intensive Properties

standard reduction potential of cell is also an intensive property since the voltage difference is the same and does not depend on how much of the reaction occurs.
Thu Feb 13, 2020 6:01 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Cv vs Cp
Replies: 17
Views: 282

Re: Cv vs Cp

the values are usually given to us, unless it's for an ideal gas, in which the equation sheet gives the formula.
Thu Feb 13, 2020 5:59 pm
Forum: Administrative Questions and Class Announcements
Topic: homework
Replies: 3
Views: 45

homework

For this week's homework, can we do problems from thermodynamics, and any one of the problems from focus 4F-J?
Thu Feb 13, 2020 5:56 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Midterm Curve
Replies: 45
Views: 517

Re: Midterm Curve

how soon does he usually have it graded and back to us?
Tue Feb 11, 2020 6:54 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 4I.9 Irreversible Expansion
Replies: 2
Views: 33

Re: 4I.9 Irreversible Expansion

In isothermal irreversible free expansion there is no work done as there is no external external pressure. The basic difference between reversible and irreversible processes is that in the reversible process the system remains in thermodynamic equilibrium, while in the irreversible process the syste...
Tue Feb 11, 2020 6:49 pm
Forum: Phase Changes & Related Calculations
Topic: 4D.7
Replies: 2
Views: 50

4D.7

Not sure if this question has been asked, but the problem states: "Oxygen difluoride is a colorless, very poisonous gas that reacts rapidly and exothermically with water vapor to produce 02 and HF. Delta H= -1368 kJ. What is the change in internal energy for the reaction of 1 mol of OF2?" ...
Thu Feb 06, 2020 8:58 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzmann Constant
Replies: 2
Views: 23

Re: Boltzmann Constant

the constant defines the relation between absolute temperature and the kinetic energy contained in each molecule of an ideal gas. energy in a gas molecule is proportional to the temperature. as temp increases, kinetic energy increases which means pressure increases if the volume is constant.
Thu Feb 06, 2020 8:54 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Free energy
Replies: 6
Views: 121

Free energy

what is the relationship between standard free energy and free energy change?
Wed Feb 05, 2020 6:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 7
Views: 102

Midterm

have the UAs posted a midterm review yet?
Wed Feb 05, 2020 6:02 pm
Forum: Phase Changes & Related Calculations
Topic: ΔH
Replies: 4
Views: 72

ΔH

I remember discussing how to find ΔH(Fusion/Vaporization) but I can't find it in my notes. Can someone please eloborate a bit on the equation used? and if we are told to calculate heat of fusion (q), will we be given ΔHf?
Wed Feb 05, 2020 5:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Max work
Replies: 2
Views: 29

Max work

Can someone explain how max work= W(reversible)?
Thu Jan 30, 2020 12:45 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4A.3 part c
Replies: 4
Views: 63

Re: 4A.3 part c

the change in internal energy is from doing work so essentially Δv=w=28J. my solution manual also agrees with 28J.
Thu Jan 30, 2020 12:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Thermal Equilibrium
Replies: 1
Views: 17

Re: Thermal Equilibrium

When two systems are in contact with each other and no energy flow takes place between them, then the two systems are said to be in thermal equilibrium with each other. I found a great example in understanding the concept from Khan Academy. "For instance, let's say you have a bowl of hot soup a...
Thu Jan 30, 2020 12:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpy
Replies: 2
Views: 35

Bond enthalpy

how do we use bond enthalpies to calculate ΔH? and was that the least inaccurate method?
Wed Jan 29, 2020 5:49 pm
Forum: Phase Changes & Related Calculations
Topic: energy of a system
Replies: 4
Views: 67

energy of a system

can someone briefly explain the piston example the professor did in class today? how would the energy of the system decrease?
Mon Jan 27, 2020 10:47 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework sections
Replies: 7
Views: 80

Re: Homework sections

the concepts in focus 4a, 4b and 4c have been covered in class
Thu Jan 23, 2020 5:48 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D.15
Replies: 1
Views: 90

6D.15

is the solution manual set up for 6D.15 and 17 wrong? the chemical equations they have presented is for different molecules so im having a hard time figuring out what is right vs wrong in the answer.
Thu Jan 23, 2020 1:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% rule
Replies: 13
Views: 131

Re: 5% rule

is the formula to check to see if the answer is in the 5% range x/[HA]x100% (given its an acid). and isn't this the same formula to find percent deprotonated?
Wed Jan 22, 2020 6:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: test 1 worksheet
Replies: 1
Views: 45

Re: test 1 worksheet

commenting so I know if anyone posts it as well :)
Wed Jan 22, 2020 5:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW 5I.35
Replies: 2
Views: 29

HW 5I.35

can someone explain how to approach that hw problem. the answer is k=p^2/(1-2p)^2. I don't understand the reasoning behind the answer for the denominator.
Mon Jan 20, 2020 3:59 pm
Forum: Student Social/Study Group
Topic: Test 1
Replies: 9
Views: 150

Test 1

are there any past exams to help us study for test 1? does the professor usually post a practice test beforehand?
Mon Jan 20, 2020 3:51 pm
Forum: Identifying Acidic & Basic Salts
Topic: Buffers
Replies: 1
Views: 72

Buffers

Can someone explain what the professor was saying about buffers on Friday. what makes a buffer/what are its properties?
Thu Jan 16, 2020 7:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.19
Replies: 2
Views: 22

Re: 6A.19

did you happen to get 3.2x10^-15 as the solution for 3.1M?
Thu Jan 16, 2020 7:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pOH
Replies: 1
Views: 24

Re: pOH

if this is for 6A.19, I did [OH-]=kw/[H3O+] and got 3.2x10^-15 as well. curious to know if it's a mistake in the solution manual or we are missing something.
Thu Jan 16, 2020 6:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in Equilibrium Constant Eq.
Replies: 3
Views: 26

Re: Water in Equilibrium Constant Eq.

if a different solvent was used, besides water, would it be included in the calculations?
Thu Jan 16, 2020 2:11 pm
Forum: Ideal Gases
Topic: Topics for Test 1
Replies: 17
Views: 210

Re: Topics for Test 1

has anyone done the peer learning worksheets? are the problems beginner level to provide guidance or a great tool to use when studying for the tests?
Tue Jan 14, 2020 12:29 pm
Forum: Polyprotic Acids & Bases
Topic: 6E.1
Replies: 1
Views: 68

6E.1

the outline mentions to look over box 6E.1 that illustrates the acidity constants of polyprotic acids. do we have to memorize them or just understand the reasoning?
Wed Jan 08, 2020 10:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Writing K expression with or without aq?
Replies: 5
Views: 64

Re: Writing K expression with or without aq?

Aqueous solutions are included since it's not a pure liquid. it is present as a water solution, but it may change how it behaves in a reaction. anything labeled as a liquid is a pure substance therefore not included when calculating K. pure liquids and solids have activities that are equal to 1.
Wed Jan 08, 2020 7:21 pm
Forum: Student Social/Study Group
Topic: Discussion Sections
Replies: 7
Views: 96

Re: Discussion Sections

Also, are the peer learning worksheets the same each week?
Wed Jan 08, 2020 7:13 pm
Forum: Student Social/Study Group
Topic: Discussion Sections
Replies: 7
Views: 96

Re: Discussion Sections

did the Professor mention how many discussion sections you can miss without losing points?
Wed Jan 08, 2020 7:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K for Gases
Replies: 12
Views: 96

Re: K for Gases

Can someone explain 5H.1?
Tue Jan 07, 2020 10:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 156

Re: Q vs K

I'm not sure if this has been asked, but how did you guys come to the conclusion for the answer to 5G.11a. I understand that to find Q, its the same process as finding K, but the solution manual for 11a doesn't show that.