Search found 49 matches

by Lisa Werner 2F
Wed Feb 13, 2019 12:05 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 3/2R vs 5/2R
Replies: 8
Views: 39

3/2R vs 5/2R

how can we tell when to use 3/2R and 5/2R as C?
by Lisa Werner 2F
Tue Feb 12, 2019 4:22 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: deltaU=0
Replies: 3
Views: 18

Re: deltaU=0

delta u is 0 when q=-w
by Lisa Werner 2F
Tue Feb 12, 2019 4:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 6
Views: 79

Re: Midterm

I believe everything in that lecture could be in it, except for the Gibbs free energy.
by Lisa Werner 2F
Tue Feb 12, 2019 4:17 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: temp units
Replies: 3
Views: 13

Re: temp units

You should do the calculations with kelvin.
by Lisa Werner 2F
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: 1
Views: 17

Do we have discussion on the day of the midterm?

Do we have discussion on the day of the midterm?
by Lisa Werner 2F
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: 28

Re: U total - 3/2nRT

Also, I believe it can only be used for ideal gases.
by Lisa Werner 2F
Tue Feb 05, 2019 7:25 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy
Replies: 3
Views: 42

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.
by Lisa Werner 2F
Tue Feb 05, 2019 7:22 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 3
Views: 16

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...
by Lisa Werner 2F
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: 21

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.
by Lisa Werner 2F
Sun Jan 27, 2019 4:10 pm
Forum: Phase Changes & Related Calculations
Topic: Why are phase changes endothermic?
Replies: 11
Views: 49

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.
by Lisa Werner 2F
Sun Jan 27, 2019 4:06 pm
Forum: Phase Changes & Related Calculations
Topic: Week 4 Homework
Replies: 12
Views: 96

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.
by Lisa Werner 2F
Tue Jan 22, 2019 8:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Polyprotic Solutions on Test 1?
Replies: 1
Views: 33

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?
by Lisa Werner 2F
Tue Jan 15, 2019 2:57 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient
Replies: 8
Views: 63

Re: Reaction Quotient

K specifically describes the reaction at equilibrium, whereas Q can describe the reaction at any time.
by Lisa Werner 2F
Tue Jan 15, 2019 2:55 pm
Forum: Ideal Gases
Topic: pressure
Replies: 7
Views: 59

Re: pressure

Pressure can be changed by changing the temperature or adding an inert gas without changing the volume.
by Lisa Werner 2F
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: 89

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.
by Lisa Werner 2F
Thu Jan 10, 2019 8:58 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Spontaneous reverse reaction? [ENDORSED]
Replies: 4
Views: 41

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.
by Lisa Werner 2F
Thu Jan 10, 2019 8:56 pm
Forum: Student Social/Study Group
Topic: New to Lavelle
Replies: 32
Views: 408

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.
by Lisa Werner 2F
Thu Jan 10, 2019 8:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kp [ENDORSED]
Replies: 4
Views: 48

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.
by Lisa Werner 2F
Sat Dec 08, 2018 8:43 pm
Forum: Naming
Topic: bis-, tris-, etc.
Replies: 4
Views: 32

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?
by Lisa Werner 2F
Sat Dec 08, 2018 5:51 pm
Forum: Dipole Moments
Topic: London Dispersion
Replies: 5
Views: 73

Re: London Dispersion

If a molecule has many atoms with high polarizability, the LDF can actually be quite strong.
by Lisa Werner 2F
Sat Dec 08, 2018 5:48 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: HOCl vs HOI
Replies: 9
Views: 59

Re: HOCl vs HOI

Cl is more electronegative, making the electron density around the H atom less. Therefore, it can more easily be donated.
by Lisa Werner 2F
Sat Dec 08, 2018 5:46 pm
Forum: Lewis Acids & Bases
Topic: Binary Acids with H
Replies: 1
Views: 24

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?
by Lisa Werner 2F
Sat Dec 08, 2018 5:35 pm
Forum: Lewis Acids & Bases
Topic: H vs H30+
Replies: 2
Views: 18

Re: H vs H30+

To expand from the previous reply, their concentrations are therefore interchangeable in the pH equation.
by Lisa Werner 2F
Sat Dec 08, 2018 5:30 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strengths of H2S vs H2Se
Replies: 1
Views: 22

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.
by Lisa Werner 2F
Sat Dec 08, 2018 5:25 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 7
Views: 48

Re: pH formula?

I think you also need to know that pH + pOH = 14.
by Lisa Werner 2F
Sat Dec 08, 2018 5:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Shape vs Molecular Geometry
Replies: 3
Views: 31

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.
by Lisa Werner 2F
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: 25

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.
by Lisa Werner 2F
Sat Dec 08, 2018 5:08 pm
Forum: SI Units, Unit Conversions
Topic: Final Time
Replies: 1
Views: 32

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?
by Lisa Werner 2F
Sat Dec 08, 2018 5:01 pm
Forum: Sigma & Pi Bonds
Topic: Test 3 Q3D
Replies: 4
Views: 36

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.
by Lisa Werner 2F
Sat Dec 08, 2018 4:54 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty
Replies: 1
Views: 25

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.
by Lisa Werner 2F
Sat Dec 08, 2018 4:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Concept of Chelation
Replies: 3
Views: 35

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.
by Lisa Werner 2F
Sat Dec 08, 2018 4:38 pm
Forum: Naming
Topic: polydentate?
Replies: 2
Views: 24

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.
by Lisa Werner 2F
Sun Nov 11, 2018 7:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm [ENDORSED]
Replies: 14
Views: 255

Re: Midterm [ENDORSED]

my TA said that the midterms will be handed out after lecture on Wednesday
by Lisa Werner 2F
Sun Nov 11, 2018 7:13 pm
Forum: Lewis Structures
Topic: Formal charges
Replies: 15
Views: 111

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.
by Lisa Werner 2F
Sun Nov 11, 2018 7:08 pm
Forum: Electronegativity
Topic: Electron Affinity vs. Ionization Energy
Replies: 8
Views: 86

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
by Lisa Werner 2F
Sat Nov 03, 2018 8:58 pm
Forum: Lewis Structures
Topic: Brackets around ions
Replies: 2
Views: 33

Re: Brackets around ions

I would assume that you should always include the brackets during the exam just to safe.
by Lisa Werner 2F
Sat Nov 03, 2018 8:56 pm
Forum: Octet Exceptions
Topic: Formal charge
Replies: 7
Views: 74

Re: Formal charge

Yes because it will determine where the double bond should go
by Lisa Werner 2F
Sat Nov 03, 2018 8:31 pm
Forum: Lewis Structures
Topic: Expanded Valence Shells
Replies: 2
Views: 18

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.
by Lisa Werner 2F
Mon Oct 22, 2018 1:30 pm
Forum: *Particle in a Box
Topic: Midterm
Replies: 14
Views: 401

Re: Midterm

I believe it will be cumulative from the beginning of the course.
by Lisa Werner 2F
Mon Oct 22, 2018 1:27 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: What is the equation used for?
Replies: 9
Views: 97

Re: What is the equation used for?

More specifically, it determines the MINIMUM uncertainty of the position.
by Lisa Werner 2F
Mon Oct 22, 2018 1:20 pm
Forum: Properties of Light
Topic: kg or g [ENDORSED]
Replies: 11
Views: 181

Re: kg or g [ENDORSED]

Kg is used because it is the SI unit.
by Lisa Werner 2F
Mon Oct 15, 2018 2:47 pm
Forum: Student Social/Study Group
Topic: Note Taking
Replies: 25
Views: 787

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.
by Lisa Werner 2F
Mon Oct 15, 2018 2:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 86
Views: 25201

Re: Advice from a Medical Student [ENDORSED]

Thank you so much for this insight!
by Lisa Werner 2F
Mon Oct 15, 2018 2:39 pm
Forum: SI Units, Unit Conversions
Topic: How does grading for discussion posts work?
Replies: 73
Views: 1298

Re: How does grading for discussion posts work?

My T.A. said that the deadline for the posts each week is Sunday night!
by Lisa Werner 2F
Sun Oct 07, 2018 8:30 pm
Forum: SI Units, Unit Conversions
Topic: mol vs. mmol
Replies: 12
Views: 222

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.
by Lisa Werner 2F
Sun Oct 07, 2018 8:24 pm
Forum: Molarity, Solutions, Dilutions
Topic: Atomic Weight, Molecular Weight, Formula Weight [ENDORSED]
Replies: 2
Views: 59

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.
by Lisa Werner 2F
Sat Oct 06, 2018 12:13 pm
Forum: Significant Figures
Topic: Rounding numbers ending in 5
Replies: 9
Views: 70

Re: Rounding numbers ending in 5

I have always been taught to round up numbers ending in 5 as well.

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