## Search found 53 matches

Wed Mar 14, 2018 7:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating Standard Cell Potential
Replies: 2
Views: 193

### Re: Calculating Standard Cell Potential

Wed Mar 14, 2018 7:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Is enthalpy a state function?
Replies: 12
Views: 1083

### Re: Is enthalpy a state function?

Yes enthalpy is a state function.
Wed Mar 14, 2018 7:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: The First Law
Replies: 6
Views: 530

### Re: The First Law

Yes it's the same
Mon Mar 12, 2018 2:59 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant? [ENDORSED]
Replies: 5
Views: 435

### Re: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant?[ENDORSED]

For part b) isn't the answer no effect? The textbook says catalysts have no effect on the equilibrium composition.
Mon Mar 05, 2018 11:45 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Quiz 3
Replies: 3
Views: 221

### Re: Quiz 3

I think it's up to #39, but I'd take a look at the integrated exercises
Mon Mar 05, 2018 11:30 am
Forum: General Rate Laws
Topic: zero order in rate laws
Replies: 8
Views: 494

### Re: zero order in rate laws

You can leave it out because it has no effect on the rate.
Mon Mar 05, 2018 11:22 am
Forum: Zero Order Reactions
Topic: Will we need to know how to derive equations? [ENDORSED]
Replies: 9
Views: 601

### Re: Will we need to know how to derive equations?[ENDORSED]

Wed Feb 28, 2018 9:29 pm
Forum: Zero Order Reactions
Topic: Negative order
Replies: 4
Views: 314

### Re: Negative order

I looked up negative order and apparently it indicates that the concentration of that species inversely affects the rate of the reaction. I'll link the site below

https://chem.libretexts.org/Core/Physic ... tion_Order
Wed Feb 28, 2018 9:20 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Homework for Test 3
Replies: 2
Views: 240

### Re: Homework for Test 3

We stop after #39 I believe
Wed Feb 28, 2018 8:43 pm
Forum: First Order Reactions
Topic: Derivation
Replies: 8
Views: 449

### Re: Derivation

My TA said we won't have to do any derivations on the test, but knowing them does help increase understanding of the concepts
Tue Feb 27, 2018 10:24 pm
Forum: First Order Reactions
Topic: First Order Reaction Equations
Replies: 3
Views: 230

### Re: First Order Reaction Equations

It's the same thing, you should get the same answer.
Fri Feb 23, 2018 12:38 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Electrodes
Replies: 4
Views: 294

### Re: Inert Electrodes

allyz1F wrote:What about for salt bridges too? When do you know to include a salt bridge in the cell diagram and when is it not necessary?

The salt bridge maintains the charges between the anode and cathode so the reaction can happen, but you don't always have to use a salt bridge. Porous disks work as well.
Fri Feb 23, 2018 12:35 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram
Replies: 4
Views: 271

### Re: Cell diagram

chem mod posted in another post that electrodes and solids are furthest from the salt bridge, followed by liquids, gases, and aqueous solutions, but most people usually order it reactants to products
Fri Feb 23, 2018 12:29 am
Forum: Balancing Redox Reactions
Topic: Finding half reactions
Replies: 4
Views: 296

### Re: Finding half reactions

The half reactions are given on the test
Fri Feb 16, 2018 8:39 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Work
Replies: 5
Views: 361

### Re: Work

Yes, w=0.
Fri Feb 16, 2018 8:07 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Delta G standard
Replies: 4
Views: 290

### Re: Delta G standard

Either way is fine
Fri Feb 16, 2018 7:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Equilibrium
Replies: 4
Views: 211

### Re: Equilibrium

The current should stop
Tue Feb 06, 2018 10:43 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
Replies: 3
Views: 185

### Re: Boltzmann

kb is Boltzmann's constant, and it's given to us in the constants and formulas sheet
Tue Feb 06, 2018 10:21 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Test question [ENDORSED]
Replies: 16
Views: 877

### Re: Test question[ENDORSED]

They accepted multiple answers. Mine was "energy cannot be created or destroyed; it must be exchanged."
Tue Feb 06, 2018 8:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Bruin Cast
Replies: 5
Views: 426

### Re: Bruin Cast

No it's not bruincasted
Tue Jan 30, 2018 11:36 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.3
Replies: 5
Views: 333

### Re: 9.3

The signs dictate the flow of energy
Tue Jan 30, 2018 10:47 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Homework 9.13
Replies: 2
Views: 171

### Re: Homework 9.13

I think it's just to make calculations simpler
Tue Jan 30, 2018 10:45 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1411197

### Re: Post All Chemistry Jokes Here

What kind of dogs do chemists have?

Laboratory retrievers
Mon Jan 22, 2018 11:59 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Average Kinetic Energy
Replies: 2
Views: 165

### Re: Average Kinetic Energy

8.103 is a suggested problem though, so I'd know how to do it
Mon Jan 22, 2018 11:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 3 Test Topic is endorsed
Replies: 37
Views: 2932

### Re: Week 3 Test Topic is endorsed

Lauryn Jordan 1F wrote:will internal energy be on the test?

We won't be required to solve for internal energy, I believe, but there will probably be concept questions on it.
Mon Jan 22, 2018 11:46 pm
Forum: Phase Changes & Related Calculations
Topic: Problem 8.43
Replies: 5
Views: 242

### Re: Problem 8.43

Gurkriti Ahluwalia 1K wrote:can someone therefore explain why a isn't the correct choice also??

I think A isn't the correct choice either because melting is supposed to occur twice as fast as vaporization. In A, it's the opposite; vaporization occurs twice as fast as melting.
Tue Jan 16, 2018 10:46 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Is there a way specific way to approach into seeing if open closed or isolated?
Replies: 9
Views: 499

### Re: Is there a way specific way to approach into seeing if open closed or isolated?

Are you referring to 8.1?
Tue Jan 16, 2018 8:26 pm
Forum: Administrative Questions and Class Announcements
Topic: Acids and Bases
Replies: 3
Views: 191

### Re: Acids and Bases

I just checked the outlines on the Chem 14B website, and I don't see any acid/base stuff. I could be wrong though.
Tue Jan 16, 2018 8:11 pm
Forum: Phase Changes & Related Calculations
Topic: Types of Systems
Replies: 10
Views: 777

### Re: Types of Systems

^^I don't think so. The textbook only defines open, closed, and isolated systems.
Fri Jan 12, 2018 6:51 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1411197

### Re: Post All Chemistry Jokes Here

I can't tell you any good chemistry jokes because all the good ones argon.
Fri Jan 12, 2018 6:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Times to post per week
Replies: 5
Views: 398

### Re: Times to post per week

Yes 3 a week, and they don't rollover so you can't make up points.
Fri Jan 12, 2018 5:40 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Are there any periodic trends for enthalpy?
Replies: 4
Views: 207

### Re: Are there any periodic trends for enthalpy?

No, I don't think so
Sun Dec 10, 2017 12:13 am
Forum: Sigma & Pi Bonds
Topic: Delocalization of Pi bonds
Replies: 1
Views: 271

### Re: Delocalization of Pi bonds

Delocalized just means that your electrons can move around, so it's associated with resonance structures.
Sun Dec 10, 2017 12:11 am
Forum: Lewis Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 1
Views: 177

### Re: Conjugate Acids and Bases

Yes; if an acid is strong, it'll have a weak conjugate base. If an acid is weak, it'll have a strong conjugate base.
Sun Dec 10, 2017 12:03 am
Forum: Lewis Acids & Bases
Topic: CONJUGATE
Replies: 3
Views: 253

### Re: CONJUGATE

Yes
Sat Dec 09, 2017 11:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Mono/poly Dentates
Replies: 1
Views: 182

### Re: Mono/poly Dentates

At one of the review sessions, we were told to just count up the nitrogens!
Sat Dec 09, 2017 11:24 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Test 4 #6
Replies: 1
Views: 244

### Re: Test 4 #6

When you plug 2.6 into 5-2x, you get a negative value
Wed Dec 06, 2017 5:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Will we be given Table 11.2?
Replies: 2
Views: 202

### Re: Will we be given Table 11.2?

I'm pretty sure we don't have to memorize it.
Wed Dec 06, 2017 5:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.25 [ENDORSED]
Replies: 2
Views: 160

### Re: 11.25[ENDORSED]

I believe it's because the problem asks for equilibrium concentration, rather than partial pressure. If you look at 11.27, it asks for partial pressure instead, and you would use the notation with "P."
Tue Dec 05, 2017 10:35 pm
Forum: Dipole Moments
Topic: Dipole Moments and Polarity
Replies: 9
Views: 537

### Re: Dipole Moments and Polarity

It also helps to just remember Fluorine is the most electronegative, so you know elements to the upper right will be very electronegative.
Tue Dec 05, 2017 10:07 pm
Forum: Naming
Topic: Nitrogen and Ligands
Replies: 2
Views: 247

### Re: Nitrogen and Ligands

Usually, coordination # = # of the bonds linked to the central atom (usually a metal from what we've been doing)
Tue Dec 05, 2017 10:04 pm
Forum: Naming
Replies: 2
Views: 142

Isn't it usually the metal?
Tue Dec 05, 2017 9:55 pm
Forum: Sigma & Pi Bonds
Topic: Delocalized Pi-Bonding
Replies: 5
Views: 533

### Re: Delocalized Pi-Bonding

It is delocalized because the e- can move around, resulting in resonance structures. This is only seen when a pi-bond is present.
Tue Dec 05, 2017 9:40 pm
Forum: Coordinate Covalent Bonds
Topic: Naming - Prefixes
Replies: 2
Views: 502

### Naming - Prefixes

How do we know when to use the prefixes: bis-, tris-, tetrakis-, etc.?
Tue Dec 05, 2017 9:23 pm
Forum: Dipole Moments
Topic: Dipole moments and Formal Charges
Replies: 2
Views: 286

### Re: Dipole moments and Formal Charges

I think you're supposed compare the electronegativity of the atoms and their respective arrangement in the shape of the molecule; this should help you determine dipole moments. This in turn should help determine polarity.
Tue Dec 05, 2017 9:01 pm
Forum: Dipole Moments
Topic: Dipole Moments and Polarity
Replies: 9
Views: 537

### Re: Dipole Moments and Polarity

Aren't we just supposed to analyze the electronegativity trend on the periodic table? It increases as you go left to right, and as you go up a group.
Tue Dec 05, 2017 8:41 pm
Forum: Sigma & Pi Bonds
Topic: Double Bond Being Pi+Pi
Replies: 2
Views: 232

### Re: Double Bond Being Pi+Pi

^^ Yeah a double bond cannot consist of two pi bonds
Tue Dec 05, 2017 8:38 pm
Forum: Photoelectric Effect
Topic: Midterm question [ENDORSED]
Replies: 6
Views: 476

### Re: Midterm question[ENDORSED]

@Helen, not necessarily because we don't know if the threshold has been surpassed
Tue Dec 05, 2017 8:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1411197

### Re: Post All Chemistry Jokes Here

I'm female.

Fe = Iron
Male = man

Therefore, I am Iron Man.
Tue Dec 05, 2017 8:22 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1411197

### Re: Post All Chemistry Jokes Here

Don't get chemists angry, they overreact.
Tue Dec 05, 2017 8:20 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1411197

### Re: Post All Chemistry Jokes Here

What's the formula for seawater?

CH20
Sat Oct 21, 2017 12:39 am
Forum: Properties of Light
Topic: Planck's Constant
Replies: 10
Views: 675

### Re: Planck's Constant

Don't forget that the units for Planck's Constant are joules times seconds!
Wed Oct 18, 2017 10:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Module Q28
Replies: 2
Views: 223

### Atomic Spectra Module Q28

How would you approach this problem from the modules? The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radiation? To what region of the electromagnetic spectrum does this wavelength c...