Search found 66 matches

by Marcela Udave 1F
Mon Mar 11, 2019 11:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D7 temperature
Replies: 2
Views: 58

Re: 4D7 temperature

I believe it's because it's a constant temperature.
by Marcela Udave 1F
Mon Mar 11, 2019 11:43 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 7th edition 6N.15
Replies: 1
Views: 49

Re: 7th edition 6N.15

6N.15
Calculate the potential of a cell constructed with two nickel electrodes. The electrolyte in one compartment is 1.0M Ni(NO3)2(aq). In the other compartment, NaOH has been added to a Ni(NO3)2 solution until the pH=11.0 at 298K. See Table 6I.1.
by Marcela Udave 1F
Mon Mar 11, 2019 11:35 pm
Forum: Student Social/Study Group
Topic: Studying for the Final
Replies: 25
Views: 740

Re: Studying for the Final

Yeah, I plan on doing the homework problems, the tests and midterm questions.
by Marcela Udave 1F
Sun Mar 10, 2019 8:24 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Final Material
Replies: 4
Views: 56

Re: Final Material

I think questions that are also brought up on chemistry community.
by Marcela Udave 1F
Wed Mar 06, 2019 7:49 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Disproportionation
Replies: 1
Views: 62

Re: Disproportionation

I believe disproportionation usually involves redox reaction; disproportionation reactions follow the form: 2A → A' + A"
by Marcela Udave 1F
Wed Mar 06, 2019 7:45 pm
Forum: Student Social/Study Group
Topic: Final
Replies: 24
Views: 745

Re: Final

I believe the sessions start Saturday but he has yet to give the times.
by Marcela Udave 1F
Sat Mar 02, 2019 12:22 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.3
Replies: 2
Views: 55

Re: 6M.3

Sorry! What I meant to say was why was C(gr) not included in Sn4+(aq)+2e- → Sn2+(aq) ?
by Marcela Udave 1F
Wed Feb 27, 2019 6:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: platinum [ENDORSED]
Replies: 6
Views: 138

Re: platinum [ENDORSED]

You add Pt to the side that doesn't have a solid.
by Marcela Udave 1F
Wed Feb 27, 2019 6:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential [ENDORSED]
Replies: 2
Views: 58

Re: Standard Cell Potential [ENDORSED]

The standard cell potential measures the driving force for a given redox reaction.
by Marcela Udave 1F
Wed Feb 27, 2019 12:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.3
Replies: 2
Views: 55

6M.3

6M.3 Predict the standard potential of each of the following galvanic cells:
For part d, why is C(gr) not included for the anode?
(d) C(gr)|Sn4+ (aq),Sn2+ (aq)||Pb4+ (aq),Pb2+ (aq)| Pt(s)
by Marcela Udave 1F
Wed Feb 27, 2019 12:15 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 3
Views: 66

Re: Cell Diagram

Okay that makes sense. Thank you!
by Marcela Udave 1F
Tue Feb 26, 2019 10:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 3
Views: 66

Cell Diagram

Why isn't H2O included in the cell diagram?
by Marcela Udave 1F
Tue Feb 26, 2019 10:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt
Replies: 2
Views: 39

Re: Pt

I think you include it if you have gases and there's no solids.
by Marcela Udave 1F
Mon Feb 25, 2019 2:15 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Voltage
Replies: 2
Views: 54

Re: Voltage

If I'm not mistaken, it's just a matter of preference.
by Marcela Udave 1F
Mon Feb 25, 2019 2:13 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: DeltaG at Equilibrium
Replies: 2
Views: 46

Re: DeltaG at Equilibrium

If the free energy is zero, then the reaction is at equilibrium meaning that an no more work can be done.
by Marcela Udave 1F
Sun Feb 24, 2019 11:52 pm
Forum: Balancing Redox Reactions
Topic: balancing redox reactions
Replies: 2
Views: 57

Re: balancing redox reactions

I second that, they can get confusing. Tips would be helpful!
by Marcela Udave 1F
Sun Feb 24, 2019 11:51 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridges
Replies: 3
Views: 58

Re: Salt Bridges

Potassium chloride or sodium chloride are usually used.
by Marcela Udave 1F
Sat Feb 23, 2019 8:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: How can a change in entropy be negative?
Replies: 3
Views: 66

Re: How can a change in entropy be negative?

If there is less disorder in a system, then entropy is negative.
by Marcela Udave 1F
Sat Feb 23, 2019 8:10 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: What is the difference between entropy and free energy?
Replies: 2
Views: 70

Re: What is the difference between entropy and free energy?

Gibbs free energy is energy available to do work and can be used to determine the spontaneity of a reaction. Entropy is a measure of the molecular disorder of a system.
by Marcela Udave 1F
Sat Feb 23, 2019 3:50 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 3
Replies: 14
Views: 271

Re: Test 3

I believe so since if ΔG=0 then it's at equilibrium.
by Marcela Udave 1F
Sat Feb 23, 2019 3:44 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Equation
Replies: 2
Views: 202

Re: Van't Hoff Equation

I'm not too certain but i think you do.
by Marcela Udave 1F
Fri Feb 22, 2019 10:17 pm
Forum: Balancing Redox Reactions
Topic: difference between oxidation and reduction
Replies: 8
Views: 119

Re: difference between oxidation and reduction

Remember that when an atom gains an electron, its reduction and when it loses electrons its oxidation.
by Marcela Udave 1F
Fri Feb 22, 2019 8:39 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta G at equilibrium
Replies: 1
Views: 36

Re: delta G at equilibrium

Gibbs free energy measures how much potential a reaction has left. Hence if the free energy is zero, then the reaction is at equilibrium, and no more work can be done.
by Marcela Udave 1F
Fri Feb 22, 2019 8:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 174

Re: Test 2

Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation!
by Marcela Udave 1F
Thu Feb 21, 2019 10:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: electrodes
Replies: 1
Views: 32

Re: electrodes

https://chem.libretexts.org/Bookshelves ... _Chemistry)/Electrochemistry/Voltaic_Cells/The_Cell_Potential

This link is very helpful in explaining cell potential!
by Marcela Udave 1F
Thu Feb 21, 2019 10:15 pm
Forum: Van't Hoff Equation
Topic: Practice Problems
Replies: 3
Views: 91

Re: Practice Problems

I haven't seen any practice problems but do you know if we'll have to have graphical methods for Van't Hoff's equation?
by Marcela Udave 1F
Wed Feb 20, 2019 9:52 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Midterm Question (#3.D)
Replies: 2
Views: 192

Re: Midterm Question (#3.D)

The solutions for the midterm are posted on the class website!
by Marcela Udave 1F
Wed Feb 20, 2019 9:39 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: entropy
Replies: 4
Views: 92

Re: entropy

Enthalpy ('H') refers to the measure of total heat content in a thermodynamic system under constant pressure whereas enthalpy is calculated in terms of change. Keep in mind the the SI unit of enthalpy is joules (J).
by Marcela Udave 1F
Wed Feb 20, 2019 9:17 pm
Forum: Balancing Redox Reactions
Topic: Week 7 Homework
Replies: 15
Views: 230

Re: Week 7 Homework

I included gibbs free energy but also added some material on thermal dynamics.
by Marcela Udave 1F
Wed Feb 20, 2019 9:10 pm
Forum: Balancing Redox Reactions
Topic: 6k.5 7th ed. Writing half reaction for basic solution
Replies: 1
Views: 44

Re: 6k.5 7th ed. Writing half reaction for basic solution

I'm actually struggling with grasping that subject too. I also thought it was oxidizing.
by Marcela Udave 1F
Sun Feb 03, 2019 10:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm
Replies: 12
Views: 217

Re: Midterm

Yes, doing all of the homework questions help a lot because you'll realize what you need to improve one and by doing so you can seek aid in one or many of the sessions.
by Marcela Udave 1F
Sun Feb 03, 2019 10:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm
Replies: 12
Views: 217

Re: Midterm

Yes, doing all of the homework questions help a lot because you'll realize what you need to improve one and by doing so you can seek aid in one or many of the sessions.
by Marcela Udave 1F
Wed Dec 05, 2018 9:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 5
Views: 151

Shape

When asked for the shape, are we always supposed to say the molecular geometry rather than the electronic geometry?
by Marcela Udave 1F
Wed Dec 05, 2018 9:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Structures
Replies: 12
Views: 197

Re: Bent Structures

Yes, they are all polar.
by Marcela Udave 1F
Wed Dec 05, 2018 9:04 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Versus Lewis
Replies: 3
Views: 76

Re: Bronsted Versus Lewis

One of the UA told me they were the same thing.
by Marcela Udave 1F
Sun Dec 02, 2018 6:32 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.73
Replies: 2
Views: 228

4.73

(a) Draw a Lewis structure for each of the following species: CH3 ; CH4; CH3 ; CH2; CH22 ; CH22 . (b) Identify each as a radical or not.

How do you identify if they're radicals or not?
by Marcela Udave 1F
Thu Nov 29, 2018 9:50 pm
Forum: Naming
Topic: Coordination Number
Replies: 3
Views: 78

Re: Coordination Number

The coordination number equals the number of ligands.
by Marcela Udave 1F
Thu Nov 29, 2018 9:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.72
Replies: 2
Views: 75

4.72

Why is NO3- nonpolar?
by Marcela Udave 1F
Thu Nov 29, 2018 8:56 pm
Forum: Sigma & Pi Bonds
Topic: Sigma bonds
Replies: 6
Views: 191

Re: Sigma bonds

They go head to head.
by Marcela Udave 1F
Thu Nov 29, 2018 8:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 6th edition 4.23
Replies: 3
Views: 86

Re: 6th edition 4.23

Yes you did but it's not the molecular formula but VSEPR formula.
by Marcela Udave 1F
Thu Nov 29, 2018 8:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polar and non polar molecules from a lewis structure
Replies: 8
Views: 183

Re: Determining polar and non polar molecules from a lewis structure

By the electronegativity difference between the atoms. If they cancel each other then it's non polar.
by Marcela Udave 1F
Tue Nov 27, 2018 11:02 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.46
Replies: 4
Views: 130

Re: 4.46

KylieY_3B wrote:I believe it's for the entire molecule.


Okay! Thank you!
by Marcela Udave 1F
Tue Nov 27, 2018 11:00 pm
Forum: Resonance Structures
Topic: Bond lengths & number of resonance structures
Replies: 3
Views: 264

Re: Bond lengths & number of resonance structures

https://www.youtube.com/watch?v=dudRIG-dRE4

That video might help clarify resonance structures and bond lengths.
by Marcela Udave 1F
Tue Nov 27, 2018 10:45 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: pi bond
Replies: 4
Views: 117

Re: pi bond

So just to clarify, as long as there's resonance then there's delocalized pi bond?
by Marcela Udave 1F
Tue Nov 27, 2018 10:38 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.17
Replies: 3
Views: 94

4.17

Predict the bond angles at the central atom of the following molecules and ions: (a) ozone, O3; (b) azide ion, N3 ; (c) cyanate ion, CNO ; (d) hydronium ion, H3O . For part a.) For the lewis structure of O3, why isn't there double bonds connecting both the oxygen to the oxygen with the lone pair? Al...
by Marcela Udave 1F
Tue Nov 27, 2018 10:21 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.46
Replies: 4
Views: 130

4.46

4.46 Describe the structure of the formamide molecule, HCONH2, in terms of hybrid orbitals, bond angles, and sigma and pi bonds. The C atom is bonded to one H atom, a terminal O atom, and the N atom. The N atom is also bonded to two H atoms. Do you get the sigma and pi bonds for the entire molecule ...
by Marcela Udave 1F
Mon Nov 26, 2018 5:01 pm
Forum: General Science Questions
Topic: Test 3
Replies: 4
Views: 153

Re: Test 3

I heard that today's lecture was also included.
by Marcela Udave 1F
Mon Nov 26, 2018 3:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CH2CHCN geometry
Replies: 3
Views: 3353

Re: CH2CHCN geometry

So for this problem we don't describe the hybrid orbitals on each carbon atom? Or by describing the CH2 we identify the hybrid orbital of Acrylonitrile?
by Marcela Udave 1F
Mon Nov 26, 2018 1:38 pm
Forum: Hybridization
Topic: Test 3
Replies: 13
Views: 243

Re: Test 3

The test covers everything up to Monday's lecture even if your discussion is on Tuesday. Just wanted to clear things up! Since in the past he has put material on the test from the lecture on Monday so now I know to study up to Monday lecture ! Thanks! Are we supposed to know everything he went over...
by Marcela Udave 1F
Sun Nov 25, 2018 11:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 4
Views: 80

Re: Molecular Shape

I think you should use the formal charge when dealing with Lewis structures so you don't loose the habit.
by Marcela Udave 1F
Sun Nov 25, 2018 10:57 pm
Forum: Lewis Structures
Topic: 4.7A Homework
Replies: 3
Views: 506

Re: 4.7A Homework

If I'm not mistaken oxygen has a double bond with sulfur.
by Marcela Udave 1F
Sun Nov 25, 2018 10:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.5 Bond Angle
Replies: 2
Views: 51

4.5 Bond Angle

b) What is the expected OClO bond angle?
Do you go from oxygen to oxygen and say it's less than 120 degrees?
by Marcela Udave 1F
Fri Nov 16, 2018 1:52 pm
Forum: Hybridization
Topic: Describing Hybridization
Replies: 3
Views: 72

Re: Describing Hybridization

There's a chart in 4.2 that has the electron arrangement, number of atomic orbitals, hybridization of the central atom, and the number of hybrid orbitals. It can be helpful since it gives a breakdown.
by Marcela Udave 1F
Fri Nov 16, 2018 1:44 pm
Forum: Hybridization
Topic: General definition/context
Replies: 2
Views: 85

Re: General definition/context

You use hybridization to explain molecular geometry hence:
linear → sp
trigonal planar → sp²
tetrahedral → sp³
trigonal pyramidal → sp³d
octahedral → sp³d²
by Marcela Udave 1F
Fri Nov 16, 2018 1:33 pm
Forum: Hybridization
Topic: How to Determine
Replies: 12
Views: 336

Re: How to Determine

Note:
Single bonds--> one sigma bond
Double bonds--> one sigma and one pie.
Triple bonds--> one sigma and two pies.
by Marcela Udave 1F
Thu Nov 15, 2018 11:49 pm
Forum: Hybridization
Topic: How to Determine
Replies: 12
Views: 336

Re: How to Determine

I don't think resonance affects it but Im not certain. That being said hybridization to explain molecular geometry.
linear → sp
trigonal planar → sp²
tetrahedral → sp³
trigonal pyramidal → sp³d
octahedral → sp³d²
by Marcela Udave 1F
Thu Nov 15, 2018 11:41 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbital Diagram
Replies: 4
Views: 343

Re: Molecular Orbital Diagram

So we don't need to know how to draw the 3D shape right?
by Marcela Udave 1F
Sun Nov 11, 2018 9:50 pm
Forum: Dipole Moments
Topic: Dipoles
Replies: 2
Views: 62

Dipoles

Just for clarification, a partially positive element does not mind sharing electrons while a partially negative receives the electrons?
by Marcela Udave 1F
Sun Nov 11, 2018 9:41 pm
Forum: Dipole Moments
Topic: Bond Lengths
Replies: 5
Views: 196

Re: Bond Lengths

The atomic size can increase the bond length.
by Marcela Udave 1F
Sun Nov 11, 2018 9:32 pm
Forum: Student Social/Study Group
Topic: Study Group Chat?
Replies: 4
Views: 135

Re: Study Group Chat?

I do not know if there's a study group but I wouldn't mind forming a study group.
by Marcela Udave 1F
Wed Oct 10, 2018 11:34 pm
Forum: Properties of Light
Topic: Photoelectric effect
Replies: 1
Views: 53

Re: Photoelectric effect

Wait..I was confused. The work function and avogrado's number is for part b. So it all works out.
by Marcela Udave 1F
Wed Oct 10, 2018 11:30 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical & Molecular Formulas
Replies: 11
Views: 712

Re: Empirical & Molecular Formulas

Yes, the empirical and molecular can defiantly be the same.
by Marcela Udave 1F
Wed Oct 10, 2018 11:27 pm
Forum: Properties of Light
Topic: Photoelectric effect
Replies: 1
Views: 53

Photoelectric effect

28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. A. What is the kinetic energy of the ejected electron? I used the fromula EK=1/2 MV^2 and got 1.99*10^-19 but I don't understand how to apply the work f...
by Marcela Udave 1F
Fri Oct 05, 2018 4:13 pm
Forum: Properties of Light
Topic: Homework Question
Replies: 2
Views: 76

Homework Question

For Tuesday, do we have to turn in seven problems that relate to quantum?
by Marcela Udave 1F
Wed Oct 03, 2018 8:39 pm
Forum: SI Units, Unit Conversions
Topic: Homework Grading Clarification [ENDORSED]
Replies: 8
Views: 301

Re: Homework Grading Clarification [ENDORSED]

We're encouraged to do as many as we can but to make it easier for the TAs we should only turn in the seven we want graded.

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