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: 404
Re: Calculating Standard Cell Potential
Yes!! This was very helpful
- 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: 2228
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: 983
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: 1162
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: 439
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: 1069
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: 1237
Re: Will we need to know how to derive equations? [ENDORSED]
Knowing the derivations can only help you not hurt you!
- Wed Feb 28, 2018 9:29 pm
- Forum: Zero Order Reactions
- Topic: Negative order
- Replies: 4
- Views: 840
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
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: 464
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: 1051
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: 554
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: 591
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: 575
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: 587
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: 792
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: 686
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: 467
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: 425
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: 1779
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: 871
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: 719
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: 354
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: 9651
- Views: 3592305
Re: Post All Chemistry Jokes Here
What kind of dogs do chemists have?
Laboratory retrievers
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: 360
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: 4877
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: 448
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: 883
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: 307
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: 1475
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: 9651
- Views: 3592305
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: 727
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: 343
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: 353
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: 284
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: 511
Re: CONJUGATE
Yes
- Sat Dec 09, 2017 11:25 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Mono/poly Dentates
- Replies: 1
- Views: 255
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: 303
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: 288
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: 250
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: 1113
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: 386
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
- Topic: Determining Linking Atom
- Replies: 2
- Views: 264
Re: Determining Linking Atom
Isn't it usually the metal?
- Tue Dec 05, 2017 9:55 pm
- Forum: Sigma & Pi Bonds
- Topic: Delocalized Pi-Bonding
- Replies: 5
- Views: 874
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: 636
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: 440
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: 1113
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: 407
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: 797
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: 9651
- Views: 3592305
Re: Post All Chemistry Jokes Here
I'm female.
Fe = Iron
Male = man
Therefore, I am Iron Man.
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: 9651
- Views: 3592305
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: 9651
- Views: 3592305
Re: Post All Chemistry Jokes Here
What's the formula for seawater?
CH20
CH20
- Sat Oct 21, 2017 12:39 am
- Forum: Properties of Light
- Topic: Planck's Constant
- Replies: 10
- Views: 1275
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: 412
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...