Search found 72 matches
- Sun Mar 17, 2019 12:42 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: adiabatic vs isothermal
- Replies: 2
- Views: 504
adiabatic vs isothermal
what is the difference between adiabatic and isothermal?
- Sat Mar 16, 2019 11:23 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Final
- Replies: 5
- Views: 920
Re: Final
i have heard from past students that there is also a large portion based on thermodynamics.
- Sat Mar 16, 2019 11:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: atm to torr
- Replies: 3
- Views: 677
atm to torr
what is the conversion from atm to torr?
- Sat Mar 16, 2019 11:18 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: A in the arrhenius equation
- Replies: 2
- Views: 817
A in the arrhenius equation
conceptually, what does A mean in the arrhenius equation mean?
- Sat Mar 16, 2019 11:15 pm
- Forum: First Order Reactions
- Topic: Rate Law
- Replies: 4
- Views: 652
Re: Rate Law
lyndon said that we probably wouldn't have to know how to derive equations, but if it's on the syllabus it may appear on the test
- Sat Mar 16, 2019 11:13 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: adiabatic systems
- Replies: 10
- Views: 1010
Re: adiabatic systems
it means that q=0, so delta=w. it will usually be specified in the problem.
- Sat Mar 16, 2019 11:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7698
Re: LYNDON'S PORK RAMEN REVIEW
thank you lyndon !!!
- Sat Mar 16, 2019 11:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Porous Disk vs Salt Bridge
- Replies: 3
- Views: 627
Re: Porous Disk vs Salt Bridge
yes, a porous disc is notated by a single line
- Sat Mar 16, 2019 11:08 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
- Replies: 179
- Views: 25298
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
thank you so much karen! these worksheets were so helpful!
- Sat Mar 16, 2019 11:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
- Replies: 179
- Views: 25298
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
in worksheet 5 problem 6, how do we know that work is 0?
- Sat Mar 16, 2019 10:33 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Steady State Approximation
- Replies: 3
- Views: 680
Re: Steady State Approximation
i think dr. lavelle said that he wouldn't make us do it because the math is too complicated.
- Sat Mar 16, 2019 10:32 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: when is w=0 and when is q=0?
- Replies: 6
- Views: 1031
when is w=0 and when is q=0?
when is w=0 and when is q=0? what are the key words that indicate these two conditions?
- Sat Mar 16, 2019 10:31 pm
- Forum: Van't Hoff Equation
- Topic: neutral pH not 7?
- Replies: 6
- Views: 1060
Re: neutral pH not 7?
at different temperatures, ph 7 is not always neutral.
- Thu Mar 14, 2019 12:58 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: deltaU=0
- Replies: 1
- Views: 399
deltaU=0
what are scenarios/conditions where deltaU=0?
- Sun Mar 10, 2019 6:12 pm
- Forum: Second Order Reactions
- Topic: Final
- Replies: 32
- Views: 2507
Re: Final
it will be cumulative, but watch out for topics that have not yet been tested in class (kinetics)
- Sun Mar 10, 2019 6:08 pm
- Forum: First Order Reactions
- Topic: graph
- Replies: 3
- Views: 2329
Re: graph
the actual concentration of A in first order reactions is exponentially decaying; however, we plot the y axis using ln, which gives us a linear graph with a slope
- Sun Mar 10, 2019 6:05 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Molecularity
- Replies: 3
- Views: 488
Re: Molecularity
molecularity is based upon the number of types of reactant molecules in a reaction
- Sun Mar 10, 2019 6:00 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Orders
- Replies: 2
- Views: 291
Re: Orders
the order of a reaction is equal to the sum of the powers of each term in the rate law. for example, if you had rate=[A]^2[B]^1[C]^3 then 2+1+3=6 so the order of the reaction described by that particular rate law would be 6
- Sun Mar 10, 2019 5:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Calculating E naught
- Replies: 5
- Views: 981
Re: Calculating E naught
when you find the two half reactions in the from of reductions from an original equation, whichever one has the reactants and product on the same side as the original is the cathode and the one where the reactants and products are flipped is the anode.
- Sun Mar 10, 2019 5:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm average
- Replies: 5
- Views: 668
Re: Midterm average
Dr. Lavelle announced in lecture that the midterm average was an 80%.
- Sun Mar 10, 2019 5:52 pm
- Forum: Student Social/Study Group
- Topic: Final
- Replies: 24
- Views: 2279
Re: Final
when lyndon posts his review worksheet, it will probably be announced in lecture.
- Sun Mar 10, 2019 5:47 pm
- Forum: General Rate Laws
- Topic: writing rate laws
- Replies: 4
- Views: 475
Re: writing rate laws
from my understanding: they both refer to the same equation; however, "the rate of consumption of ____" could change the sign. for example, if it is the rate of consumption of a reactant then it will be positive, but if it is the rate of consumption of a product then it will be negative.
- Sun Mar 10, 2019 5:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equation I've never seen before?
- Replies: 3
- Views: 411
Re: Equation I've never seen before?
it is just a specific case of the gas law equation pv=nrt
- Wed Feb 13, 2019 12:05 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 3/2R vs 5/2R
- Replies: 8
- Views: 2106
3/2R vs 5/2R
how can we tell when to use 3/2R and 5/2R as C?
- Tue Feb 12, 2019 4:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: deltaU=0
- Replies: 3
- Views: 464
Re: deltaU=0
delta u is 0 when q=-w
- Tue Feb 12, 2019 4:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 6
- Views: 664
Re: Midterm
I believe everything in that lecture could be in it, except for the Gibbs free energy.
- Tue Feb 12, 2019 4:17 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: temp units
- Replies: 3
- Views: 371
Re: temp units
You should do the calculations with kelvin.
- Wed Feb 06, 2019 5:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Do we have discussion on the day of the midterm?
- Replies: 2
- Views: 288
Do we have discussion on the day of the midterm?
Do we have discussion on the day of the midterm?
- Tue Feb 05, 2019 7:30 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: U total - 3/2nRT
- Replies: 3
- Views: 450
Re: U total - 3/2nRT
Also, I believe it can only be used for ideal gases.
- Tue Feb 05, 2019 7:25 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy
- Replies: 3
- Views: 512
Re: Internal Energy
Dr. Lavelle explained it in lecture and it is required for several homework problems, so I think he considers it fair game for the midterm.
- Tue Feb 05, 2019 7:22 pm
- Forum: Calculating Work of Expansion
- Topic: Work
- Replies: 3
- Views: 425
Re: Work
Is there a conceptional reason as to why a reversible reaction does more work than a reversible one? The textbook gave the example of a reversible reaction occurring in a container with the same pressure inside and outside, making the system work against the equal pressure to expand. On the other ha...
- Sun Jan 27, 2019 4:38 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 3
- Views: 227
Re: Bond Enthalpies
Bond enthalpy is the least accurate method because it based on the average enthalpies required to break a type of bond across all different types of molecules, rather than a specific molecule.
- Sun Jan 27, 2019 4:10 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why are phase changes endothermic?
- Replies: 11
- Views: 1041
Re: Why are phase changes endothermic?
Phase changes involving the breaking of bonds (solid->liquid->gas) are endothermic because they require/absorb heat. Phase changes involving the formation of bonds (gas->liquid->solid) are exothermic because the release heat.
- Sun Jan 27, 2019 4:06 pm
- Forum: Phase Changes & Related Calculations
- Topic: Week 4 Homework
- Replies: 12
- Views: 1272
Re: Week 4 Homework
Technically speaking, I believe that any homework problems are accepted, but we should begin to work on the thermodynamics outline to stay up to date in the class.
- Tue Jan 22, 2019 8:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Polyprotic Solutions on Test 1?
- Replies: 1
- Views: 223
Polyprotic Solutions on Test 1?
I noticed that one homework problem and one worksheet for this section had questions regarding polyprotic solutions, but I didn't think that they were covered in lecture. Does anyone know if they will be on Test 1 or not?
- Tue Jan 15, 2019 2:57 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 10
- Views: 829
Re: Reaction Quotient
K specifically describes the reaction at equilibrium, whereas Q can describe the reaction at any time.
- Tue Jan 15, 2019 2:55 pm
- Forum: Ideal Gases
- Topic: pressure [ENDORSED]
- Replies: 13
- Views: 1123
Re: pressure [ENDORSED]
Pressure can be changed by changing the temperature or adding an inert gas without changing the volume.
- Tue Jan 15, 2019 2:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: test 1 [ENDORSED]
- Replies: 7
- Views: 932
Re: test 1 [ENDORSED]
I am assuming that the test will include acids and bases because last quarter Dr. Lavelle tested everything covered in lecture up until the Friday before the test.
- Thu Jan 10, 2019 8:58 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Spontaneous reverse reaction? [ENDORSED]
- Replies: 4
- Views: 408
Re: Spontaneous reverse reaction? [ENDORSED]
It means that the reverse reaction is thermodynamically favored, so it is happening at a greater rate than the forward reaction.
- Thu Jan 10, 2019 8:56 pm
- Forum: Student Social/Study Group
- Topic: New to Lavelle
- Replies: 32
- Views: 5380
Re: New to Lavelle
I recommend doing as many practice problems as possible by doing those from the book and attending workshops with practice handouts.
- Thu Jan 10, 2019 8:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Kp [ENDORSED]
- Replies: 4
- Views: 2948
Re: K vs Kp [ENDORSED]
Yes, you can assume Kp as essentially the only way to find the K of homogenous gas is through the partial pressure. Similarly, you can assume Kc when dealing with the K of homogenous aqueous reactions because you use molarity to find it.
- Sat Dec 08, 2018 8:43 pm
- Forum: Naming
- Topic: bis-, tris-, etc.
- Replies: 4
- Views: 577
bis-, tris-, etc.
do we use the bis-, tris-, etc. if a ligand is a polydentate or if it has another greek prefix? basically does oxalate need them or not?
- Sat Dec 08, 2018 5:51 pm
- Forum: Dipole Moments
- Topic: London Dispersion
- Replies: 5
- Views: 1000
Re: London Dispersion
If a molecule has many atoms with high polarizability, the LDF can actually be quite strong.
- Sat Dec 08, 2018 5:48 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: HOCl vs HOI
- Replies: 9
- Views: 4290
Re: HOCl vs HOI
Cl is more electronegative, making the electron density around the H atom less. Therefore, it can more easily be donated.
- Sat Dec 08, 2018 5:46 pm
- Forum: Lewis Acids & Bases
- Topic: Binary Acids with H
- Replies: 1
- Views: 256
Binary Acids with H
In the textbook, it says if A (the element bonded to H) is more electronegative, then the acid will be stronger. However, this rule doesn't work considering between HF and HCl, F is more electronegative than Cl, but HF is a weaker acid than HCl. Why does the rule not apply?
- Sat Dec 08, 2018 5:35 pm
- Forum: Lewis Acids & Bases
- Topic: H vs H30+
- Replies: 2
- Views: 365
Re: H vs H30+
To expand from the previous reply, their concentrations are therefore interchangeable in the pH equation.
- Sat Dec 08, 2018 5:30 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strengths of H2S vs H2Se
- Replies: 1
- Views: 531
Re: Strengths of H2S vs H2Se
London dispersion forces are intermolecular forces so they only affect how the molecule interacts with others, not affect bond strength.
- Sat Dec 08, 2018 5:25 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 4659
Re: pH formula?
I think you also need to know that pH + pOH = 14.
- Sat Dec 08, 2018 5:24 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Shape vs Molecular Geometry
- Replies: 3
- Views: 520
Re: VSEPR Shape vs Molecular Geometry
They are the same thing. Electron geometry would be when lone pairs are considered when determining shape, but it seems like this is almost never considered.
- Sat Dec 08, 2018 5:10 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Churro question 38
- Replies: 1
- Views: 491
Re: Churro question 38
We have to assume from the problem that the LDF of H2Se overwhelm that of H2S because Se has a higher polarizability than S, so it has stronger LDF.
- Sat Dec 08, 2018 5:08 pm
- Forum: SI Units, Unit Conversions
- Topic: Final Time
- Replies: 1
- Views: 463
Final Time
In regards to time, does anyone know if the final will have a similar amount of time allotted to each question as the midterm? Or will we have more time?
- Sat Dec 08, 2018 5:01 pm
- Forum: Sigma & Pi Bonds
- Topic: Test 3 Q3D
- Replies: 4
- Views: 694
Re: Test 3 Q3D
There should be overlap if you are referring to the the diagram of the s hybridizing with the p orbital. If you are referring to the diagram of the bond between two atoms, there should not be overlap.
- Sat Dec 08, 2018 4:54 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty
- Replies: 1
- Views: 446
Re: Uncertainty
When you give your answer you will always use the greater than or equal to sign, unless the question is asking for the minimum uncertainty.
- Sat Dec 08, 2018 4:52 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Concept of Chelation
- Replies: 3
- Views: 409
Re: Concept of Chelation
From my understanding, chelation occurs when a polydentate ligand bonds with a central metal in more than two places, creating a ring. Therefore, only polydentate ligands can be chelating.
- Sat Dec 08, 2018 4:38 pm
- Forum: Naming
- Topic: polydentate?
- Replies: 2
- Views: 233
Re: polydentate?
you can tell if a ligand is polydentate by looking at the figure and finding the places where it could bond to a central metal, considering the angles.for example, if a ligand could bond in two places, but they are on different side of the molecule, it is still monodentate.
- Sat Dec 08, 2018 4:35 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 21974
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
thank you so much!
- Sun Nov 11, 2018 7:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm [ENDORSED]
- Replies: 14
- Views: 1592
Re: Midterm [ENDORSED]
my TA said that the midterms will be handed out after lecture on Wednesday
- Sun Nov 11, 2018 7:13 pm
- Forum: Lewis Structures
- Topic: Formal charges
- Replies: 15
- Views: 1325
Re: Formal charges
usually you do not have to write the formal charge of each atom for points unless instructed to do so, but it will help you find the correct lewis structure by demonstrating which structure will have the lowest energy.
- Sun Nov 11, 2018 7:08 pm
- Forum: Electronegativity
- Topic: Electron Affinity vs. Ionization Energy
- Replies: 8
- Views: 853
Re: Electron Affinity vs. Ionization Energy
Also note that C,N,O and F all have exceptions to the trends!
in order from least to greatest in electronic affinity: N,C,O,F
in order from least to greatest in ionization energy: C,O,N,F
in order from least to greatest in electronic affinity: N,C,O,F
in order from least to greatest in ionization energy: C,O,N,F
- Sat Nov 03, 2018 9:58 pm
- Forum: Lewis Structures
- Topic: Brackets around ions
- Replies: 2
- Views: 179
Re: Brackets around ions
I would assume that you should always include the brackets during the exam just to safe.
- Sat Nov 03, 2018 9:56 pm
- Forum: Octet Exceptions
- Topic: Formal charge
- Replies: 7
- Views: 948
Re: Formal charge
Yes because it will determine where the double bond should go
- Sat Nov 03, 2018 9:31 pm
- Forum: Lewis Structures
- Topic: Expanded Valence Shells
- Replies: 2
- Views: 237
Re: Expanded Valence Shells
I don't think that there is limit. Either way, I think it is arbitrary because finding the lowest formal charge will keep you from ever getting close to what the limit would be, so I wouldn't worry about it.
- Sat Nov 03, 2018 8:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 24204
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Thank you so much! This was really helpful!
- Mon Oct 22, 2018 2:30 pm
- Forum: *Particle in a Box
- Topic: Midterm
- Replies: 17
- Views: 4308
Re: Midterm
I believe it will be cumulative from the beginning of the course.
- Mon Oct 22, 2018 2:27 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What is the equation used for?
- Replies: 9
- Views: 883
Re: What is the equation used for?
More specifically, it determines the MINIMUM uncertainty of the position.
- Mon Oct 22, 2018 2:20 pm
- Forum: Properties of Light
- Topic: kg or g [ENDORSED]
- Replies: 11
- Views: 1710
Re: kg or g [ENDORSED]
Kg is used because it is the SI unit.
- Mon Oct 15, 2018 3:47 pm
- Forum: Student Social/Study Group
- Topic: Note Taking
- Replies: 145
- Views: 20771
Re: Note Taking
I prefer taking hand-written notes in class, then going over them the next day and typing them on Google Docs. This is a good review and also ensures organization, clarity, makes it easier to find a specific subject later on.
- Mon Oct 15, 2018 3:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 479368
Re: Advice from a Medical Student [ENDORSED]
Thank you so much for this insight!
- Mon Oct 15, 2018 3:39 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9632
Re: How does grading for discussion posts work?
My T.A. said that the deadline for the posts each week is Sunday night!
- Sun Oct 07, 2018 9:30 pm
- Forum: SI Units, Unit Conversions
- Topic: mol vs. mmol
- Replies: 12
- Views: 2880
Re: mol vs. mmol
My TA taught my discussion class that a good way to convert units is to simply substitute the power of 10 associated with the prefix for the prefix when doing calculations. For example, 1 mmol would become 1x10^-3mol.
- Sun Oct 07, 2018 9:24 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Atomic Weight, Molecular Weight, Formula Weight [ENDORSED]
- Replies: 2
- Views: 267
Re: Atomic Weight, Molecular Weight, Formula Weight [ENDORSED]
From my understanding, although the atomic weight, molecular weight, and formula weight are slightly different, they can all be found by finding the total weight of the atom(s) in a given atom, molecule, or formula. Therefore, the basic concept is the same.
- Sat Oct 06, 2018 1:13 pm
- Forum: Significant Figures
- Topic: Rounding numbers ending in 5
- Replies: 9
- Views: 919
Re: Rounding numbers ending in 5
I have always been taught to round up numbers ending in 5 as well.