Search found 67 matches
- Sun Mar 18, 2018 9:24 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt electrode
- Replies: 2
- Views: 456
Re: Pt electrode
You add it when there is no solid on that side of the cell diagram. So if there is already a solid then you don't add it.
- Sat Mar 17, 2018 12:13 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.103
- Replies: 2
- Views: 472
Re: 9.103
For this question does anyone know where they got the values from??
- Thu Mar 15, 2018 11:35 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: HW 14.15
- Replies: 1
- Views: 260
Re: HW 14.15
I think it is because they are both in the same state. But can someone please confirm this?
- Tue Mar 13, 2018 11:07 am
- Forum: Balancing Redox Reactions
- Topic: Winter 2013 final Q4
- Replies: 9
- Views: 1139
Re: Winter 2013 final Q4
Here is the question
- Mon Mar 12, 2018 10:27 am
- Forum: Balancing Redox Reactions
- Topic: Half-reactions
- Replies: 4
- Views: 584
Half-reactions
Are we always supposed to flip one of the half-reactions to give you the MOST positive E value?
- Mon Mar 12, 2018 10:26 am
- Forum: Balancing Redox Reactions
- Topic: Winter 2013 final Q4
- Replies: 9
- Views: 1139
Winter 2013 final Q4
For this question, I know how to calculate everything except n. Could someone please explain how they got n because it does not explain that part? Is it the half reactions? because those are not given either...
- Mon Mar 12, 2018 9:23 am
- Forum: Experimental Details
- Topic: Final [ENDORSED]
- Replies: 4
- Views: 1427
Final [ENDORSED]
Is this topic going to be on the final?
- Wed Mar 07, 2018 10:09 am
- Forum: First Order Reactions
- Topic: Pseudo orders
- Replies: 3
- Views: 486
Re: Pseudo orders
how would you identify them?
- Wed Mar 07, 2018 10:01 am
- Forum: First Order Reactions
- Topic: Pseudo orders
- Replies: 3
- Views: 486
Pseudo orders
Are there any homework problems in the textbook that talk about this because I feel like I need practice on this or is it more of a conceptual thing??
- Wed Mar 07, 2018 9:50 am
- Forum: Zero Order Reactions
- Topic: zero order rate?
- Replies: 14
- Views: 1556
Re: zero order rate?
i'm a little confused.. how is [A] different from ln[A] or 1/[A]?
- Wed Mar 07, 2018 9:26 am
- Forum: Zero Order Reactions
- Topic: zero order rate?
- Replies: 14
- Views: 1556
zero order rate?
In my notes, I wrote down that for a zero order the rate does not depend on concentration.. is this correct or did I write down incorrect information??
- Thu Mar 01, 2018 1:23 pm
- Forum: First Order Reactions
- Topic: 15.21
- Replies: 3
- Views: 1081
Re: 15.21
I think my TA told me that it does not necessarily have to be concentration. As long as you keep it the same throughout the problem.
- Thu Mar 01, 2018 10:03 am
- Forum: Second Order Reactions
- Topic: Example?
- Replies: 4
- Views: 579
Example?
What’s a real life example of a second order reaction?
- Thu Mar 01, 2018 10:01 am
- Forum: General Rate Laws
- Topic: Differential vs integrated
- Replies: 2
- Views: 379
Differential vs integrated
What’s the significant difference between differential and integrated and when do you use either of the equations?
- Thu Mar 01, 2018 10:00 am
- Forum: Zero Order Reactions
- Topic: Zero order common?? [ENDORSED]
- Replies: 5
- Views: 722
Zero order common?? [ENDORSED]
Is zero order common or uncommon???
- Thu Feb 22, 2018 7:17 pm
- Forum: General Rate Laws
- Topic: 15.3(c)
- Replies: 2
- Views: 394
15.3(c)
For this part of the question, it asks "What is the unique rate of the reaction" and I am not really sure what it is asking me to find..?
- Tue Feb 20, 2018 8:44 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing number of electrons
- Replies: 10
- Views: 1055
Re: Balancing number of electrons
Yes because you want to make sure that the electrons cancel out when you write the final balanced redox reaction.
- Tue Feb 20, 2018 8:43 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 3
- Views: 406
Re: Cell Diagram
I think if they are in the same state then you can use commas. However, whenever there is a solid and another state involved, you have to put the line.
- Tue Feb 20, 2018 8:16 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: metals dissolving
- Replies: 1
- Views: 300
metals dissolving
How can you tell if a metal will dissolve in a solution?
- Sun Feb 18, 2018 7:08 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Reduction Potential Values
- Replies: 2
- Views: 338
Re: Standard Reduction Potential Values
Ammar Amjad 1L wrote:Appendix 2B: Standard Potentials at 25 celsius
Thank you!!!!
- Sun Feb 18, 2018 3:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Reduction Potential Values
- Replies: 2
- Views: 338
Standard Reduction Potential Values
Does anyone know where in the book we find these values??
- Sun Feb 18, 2018 3:34 pm
- Forum: Balancing Redox Reactions
- Topic: 14.9
- Replies: 1
- Views: 312
14.9
For this question it tell you to find DG and i understand that you are supposed to use the equation DG=-nFE but i am not sure how the solutions manual got the value of n.. can someone help to explain that please. Thank you.
- Thu Feb 15, 2018 10:09 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: log vs. ln [ENDORSED]
- Replies: 2
- Views: 461
log vs. ln [ENDORSED]
I have seen some NERNST equations with logQ and others with lnQ... is there a difference or is it just a change of constants when using one or the other?
- Thu Feb 15, 2018 9:58 am
- Forum: Balancing Redox Reactions
- Topic: electrons
- Replies: 3
- Views: 372
electrons
when you separate the redox reaction into the half reactions, should the electrons be put in both half reactions?
- Thu Feb 15, 2018 9:57 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Reduction Potential
- Replies: 1
- Views: 253
Standard Reduction Potential
The value for standard reduction potential will always be a given right?
- Thu Feb 08, 2018 10:33 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.83 moles
- Replies: 1
- Views: 261
Re: 9.83 moles
I think it is because HBr has a coefficient of 2 in front of it.
- Tue Feb 06, 2018 10:29 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: constant pressure and constant volume
- Replies: 3
- Views: 384
constant pressure and constant volume
I am very confused because I am doing problems in which some say constant volume = 5/2R and others say constant pressure is 5/2R. Isn't one of these supposed to be 3/2R??
- Tue Feb 06, 2018 9:57 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Differing Equations Used For delta S with Change in Temperature
- Replies: 3
- Views: 604
Re: Differing Equations Used For delta S with Change in Temperature
I think it just depends on how the problem is worded. For example, for #13, it states that it is ideal behavior. For #19, it gives the "molar heat capacities at constant pressure" which is equivalent to Cp,m. For #43, it just states that it is at constant pressure, which is equivalent to C...
- Tue Feb 06, 2018 9:49 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode vs. Cathode
- Replies: 2
- Views: 1026
Anode vs. Cathode
In Monday's lecture, Lavelle explained how the anode is the negative side and the cathode would be the positive side. However, in my biology class, when we were discussing gel electrophoresis, the anode was the positive side and the cathode was the negative side. Is there a difference between the tw...
- Mon Feb 05, 2018 5:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Equations
- Replies: 4
- Views: 506
Re: Equations
We are usually given the equations on the formula sheet so knowing how to derive should not be required.
- Mon Feb 05, 2018 5:22 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sig Figs
- Replies: 6
- Views: 708
Re: Sig Figs
Try to see what the lowest sig figs are in the problem given if that makes sense.
- Mon Feb 05, 2018 5:19 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Q vs. K
- Replies: 2
- Views: 344
Q vs. K
This is probably from 14A but are both Q and K raised to their coefficients or is it just K?
- Thu Feb 01, 2018 12:29 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Adiabatic [ENDORSED]
- Replies: 4
- Views: 480
Adiabatic [ENDORSED]
So just to make sure, this means that q=0, meaning that only work is being done by or on the system? I feel like my resoning might be wrong.
- Thu Feb 01, 2018 12:20 pm
- Forum: Calculating Work of Expansion
- Topic: Expansion
- Replies: 3
- Views: 427
Expansion
When the temperature is constant and pressure and volume are both changing, this means that work is being done BY the system right? aka expansion? or am I missing something?
- Thu Feb 01, 2018 12:07 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: DeltaS= q(rev)/T
- Replies: 1
- Views: 223
DeltaS= q(rev)/T
What determines whether q is reversible or irreversible??
- Thu Jan 25, 2018 8:30 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Chem 14A final
- Replies: 2
- Views: 394
Chem 14A final
I was not sure where to post this but does anyone know when we will be able to see our finals from last quarter???
- Mon Jan 22, 2018 4:21 pm
- Forum: Phase Changes & Related Calculations
- Topic: 8.87 Temperatures
- Replies: 5
- Views: 513
Re: 8.87 Temperatures
I think it is because 0 degrees is the melting point and 100 degrees is the boiling point and those are like important states.
- Mon Jan 22, 2018 2:13 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: N: number of particle [ENDORSED]
- Replies: 4
- Views: 507
Re: N: number of particle [ENDORSED]
so if it was asking for the number of atoms would you use avogadro's number?
- Mon Jan 22, 2018 2:05 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: N: number of particle [ENDORSED]
- Replies: 4
- Views: 507
N: number of particle [ENDORSED]
In today’s lecture, Lavelle was explaining about N being the number of particles that can occupy the states but I’m confused on the last example that he gave about the CO molecules and why he put N=4 instead of N=2
Thank you
Thank you
- Wed Jan 17, 2018 6:56 pm
- Forum: Phase Changes & Related Calculations
- Topic: 8.31
- Replies: 2
- Views: 230
Re: 8.31
If this is specific heat then i think specific heat is always given but im not sure
- Wed Jan 17, 2018 6:52 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Enthalpy Equation
- Replies: 3
- Views: 496
Re: Enthalpy Equation
PdeltaV represents work. so the equation would be deltaU= q+w and w=-PdeltaV.
- Wed Jan 17, 2018 6:48 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Question 8.29
- Replies: 2
- Views: 358
Re: Question 8.29
More complex molecules have higher specific/molar heat capacity because they have more atoms present
- Wed Jan 10, 2018 7:57 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Equations
- Replies: 6
- Views: 569
Equations
what are some general equations that we should know for like heat of fusion or heat of vaporization?
- Wed Jan 10, 2018 5:40 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: tables in chapter 8
- Replies: 5
- Views: 337
tables in chapter 8
will we be given tables like 8.3 on tests or are we supposed to memorize specific important values?
- Wed Jan 10, 2018 5:35 pm
- Forum: Phase Changes & Related Calculations
- Topic: chapter 8
- Replies: 6
- Views: 596
chapter 8
so chapter 8 starts with thermodynamics and Lavelle is starting with thermochemistry, right?
- Mon Jan 08, 2018 4:29 pm
- Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
- Topic: aqueous equilibria
- Replies: 2
- Views: 1273
aqueous equilibria
are we gonna go over this topic at all since we didn't go over it last quarter?
- Wed Dec 06, 2017 8:37 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: negligible rule [ENDORSED]
- Replies: 3
- Views: 4292
negligible rule [ENDORSED]
So when K is small enough, then X can be negligible. Does this apply only to weak acids and bases or any type of reaction?
- Wed Dec 06, 2017 8:34 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 12.23 [ENDORSED]
- Replies: 7
- Views: 1200
Re: 12.23 [ENDORSED]
I think that as long as the temp stays the same throughout the problem then it should not cause any changes in the way that you do the problem.
- Wed Nov 29, 2017 10:35 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Test 4 [ENDORSED]
- Replies: 4
- Views: 717
Test 4 [ENDORSED]
Is this topic supposed to be in test 4? I do not remember ever talking about it in class but I have heard from other students that we are required to know this.
Thank You!
Thank You!
- Tue Nov 28, 2017 5:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: chapter 4
- Replies: 1
- Views: 263
chapter 4
"Describe the structure of a molecule, cation, or anion in terms of hybrid orbitals and sigma and
pi bonds"
can someone please explain this to me?
pi bonds"
can someone please explain this to me?
- Mon Nov 20, 2017 6:45 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Binding
- Replies: 1
- Views: 203
Binding
Is it not possible there not to be a binding site when there is a double bond??
- Mon Nov 20, 2017 6:42 pm
- Forum: Biological Examples
- Topic: Ligands [ENDORSED]
- Replies: 3
- Views: 631
Ligands [ENDORSED]
Is it necessary to memorize the charges of the ligands?
- Tue Nov 14, 2017 4:42 pm
- Forum: Dipole Moments
- Topic: dipole moment arrows [ENDORSED]
- Replies: 2
- Views: 978
Re: dipole moment arrows [ENDORSED]
Yes, the arrow will always point to the most electronegative atom because the electrons are being pulled in that direction. To figure out whether a molecule is polar or non polar you need to figure out whether the dipole moments cancel. It is possible that the dipole moments will be in the same dir...
- Mon Nov 13, 2017 12:29 pm
- Forum: Dipole Moments
- Topic: dipole moment arrows [ENDORSED]
- Replies: 2
- Views: 978
dipole moment arrows [ENDORSED]
the arrow always points to the most electronegative right??
and when they point in the same direction it is polar?
and when they point in opposite directions its nonpolar?
and when they point in the same direction it is polar?
and when they point in opposite directions its nonpolar?
- Mon Nov 13, 2017 12:18 pm
- Forum: Sigma & Pi Bonds
- Topic: # of sigma and pi bonds [ENDORSED]
- Replies: 4
- Views: 583
# of sigma and pi bonds [ENDORSED]
So there is always one sigma bond and then all other bonds created after that are going to be pi bonds??
- Tue Nov 07, 2017 4:35 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Lengths [ENDORSED]
- Replies: 8
- Views: 1116
Re: Bond Lengths [ENDORSED]
are we supposed to know about pi bonds for the midterm?? I do not remember going over them in class.
- Tue Nov 07, 2017 4:08 pm
- Forum: Electronegativity
- Topic: electronegativity chart
- Replies: 11
- Views: 1790
electronegativity chart
Is it necessary to know or memorize the electronegativity chart in the book? It is figure 3.12 in the book. Will we be asked questions that require these specific values? or should we just know the trend?
Thank You!
Thank You!
- Mon Oct 30, 2017 1:17 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Chapter 2, #43 [ENDORSED]
- Replies: 3
- Views: 428
Re: Chapter 2, #43 [ENDORSED]
This follows the patterns of Copper. The reason is to make it more stable. When going to the next element, you would then fill the s subshell.
- Mon Oct 30, 2017 1:04 pm
- Forum: Lewis Structures
- Topic: HW 3.19 [ENDORSED]
- Replies: 4
- Views: 693
Re: HW 3.19 [ENDORSED]
When it is asking for electron pairs it is always helpful to draw out the orbital diagram so that you have a visual representation of it. Remember Pauli's rule and Hund's rule.
- Mon Oct 23, 2017 12:34 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy [ENDORSED]
- Replies: 1
- Views: 289
Ionization Energy [ENDORSED]
Why does the ionization energy decrease down a group? And why does it increase across a period? I don't fully understand why.
- Mon Oct 23, 2017 12:31 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals and quantum numbers [ENDORSED]
- Replies: 2
- Views: 404
Re: Orbitals and quantum numbers [ENDORSED]
Just remember that each l value corresponds to the orbitals.
l=0 corresponds to s
l=1 corresponds to p
l=2 corresponds to d
l=3 corresponds to f
l=0 corresponds to s
l=1 corresponds to p
l=2 corresponds to d
l=3 corresponds to f
- Mon Oct 16, 2017 7:09 pm
- Forum: Properties of Electrons
- Topic: Electromagnetic Spectrum
- Replies: 2
- Views: 384
Electromagnetic Spectrum
Is it necessary to memorize the chart (1.9) in the book or is it just a reference?
- Mon Oct 16, 2017 6:59 pm
- Forum: *Black Body Radiation
- Topic: Black body for quiz 2 [ENDORSED]
- Replies: 11
- Views: 1689
Re: Black body for quiz 2 [ENDORSED]
Dr. Lavelle told our lecture that we did not have to worry about black bodies for this upcoming test.
- Thu Oct 12, 2017 8:23 pm
- Forum: Properties of Electrons
- Topic: Series
- Replies: 6
- Views: 827
Re: Series
what are the n-levels associated with series that are listed above??
- Thu Oct 12, 2017 8:19 pm
- Forum: Properties of Light
- Topic: Figure 1.9
- Replies: 4
- Views: 517
Figure 1.9
So is it necessary to know or memorize this chart in the textbook for future tests?
- Thu Oct 05, 2017 12:12 am
- Forum: Balancing Chemical Reactions
- Topic: Order of molecules balanced
- Replies: 6
- Views: 1135
Re: Order of molecules balanced
For me, I look at each problem individually and I decide which element looks easiest to balance first and it usually works out. So I would just go on a problem to problem basis.
- Wed Oct 04, 2017 11:56 pm
- Forum: Balancing Chemical Reactions
- Topic: H7 // Book Problem Clarification
- Replies: 4
- Views: 797
Re: H7 // Book Problem Clarification
You do not include the catalyst in the equation because its only purpose is to speed up the process of the reaction.