Search found 69 matches

by rkang00
Sat Mar 16, 2019 7:05 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Catalyst in rate law?
Replies: 6
Views: 29

Catalyst in rate law?

Is having a catalyst in the rate law allowed? Or is it not, like intermediates aren't?
by rkang00
Sat Mar 16, 2019 6:24 pm
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
Replies: 179
Views: 5265

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)

For the electrochem worksheet 8d, why don't we include the OH- in the cell diagram?
by rkang00
Sat Mar 16, 2019 4:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate determining step & overall rate law
Replies: 1
Views: 18

Rate determining step & overall rate law

Does the rate constant k of the exp determined overall rate law equal to the rate-determining step's rate constant? What about when we assume pre-equilibrium?
by rkang00
Sat Mar 16, 2019 3:54 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Drawing reaction profiles
Replies: 2
Views: 30

Re: Drawing reaction profiles

The height of the waves depend on Ea, don't they? (higher = slower, lower = faster)
by rkang00
Fri Mar 15, 2019 10:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: H+ and OH- in cells
Replies: 1
Views: 11

H+ and OH- in cells

Do we include H+/OH- in cell diagrams ONLY if they're present in the balanced redox rxn? I'm a bit confused as to when to put them.
by rkang00
Fri Mar 15, 2019 8:23 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Catalysts
Replies: 2
Views: 27

Catalysts

Do catalysts not show up the overall rxn, but can start out in individual mechanism steps - get consumed - then get re-formed? What are the key features that define a catalyst in a rxn mechanism?
by rkang00
Fri Mar 15, 2019 8:03 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Drawing reaction profiles
Replies: 2
Views: 30

Drawing reaction profiles

When drawing profiles, how do we draw the troughs of multiple mechanisms? Don't we have to know whether each step is exo/endothermic, and do we have to know something about stability?
by rkang00
Tue Mar 12, 2019 6:20 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Unique rate?
Replies: 7
Views: 45

Re: Unique rate?

Is the 'unique' of the unique rate indicating that every single rxn has its very own unique rate, like a human fingerprint?
by rkang00
Tue Mar 12, 2019 6:17 pm
Forum: General Rate Laws
Topic: Zero Order Reactions
Replies: 4
Views: 35

Re: Zero Order Reactions

So if a reactant's order is zero, its concentration will change linearly regardless of its concentration?
by rkang00
Tue Mar 12, 2019 6:16 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediates
Replies: 2
Views: 14

Intermediates

I'm not sure how to explain what an intermediate is; is it a species that forms during mechanism, but is not in the products nor reactants of the overall rxn? Is there more to this definition?
by rkang00
Thu Feb 28, 2019 3:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: H+, OH-, water
Replies: 9
Views: 74

H+, OH-, water

If there are H+ or OH- or water left over from balancing half-rxns, do we have to list them in the cell diagram as well?
by rkang00
Thu Feb 28, 2019 2:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell diagram: solids
Replies: 1
Views: 26

cell diagram: solids

Why do we not use commas to separate solids undissolved in solution? 7th edition 6L 7c uses a single line instead of a comma; is it because the solid dissolved is not part of the electrode?
by rkang00
Thu Feb 28, 2019 1:36 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: neutralization redox
Replies: 1
Views: 36

neutralization redox

How do we know which rxns to use for neutralization redox rxns? I find it hard to tell which ones I should use. Is there a way to solve these problems in general? I think if I can just know what rxns to use, I could do the rest.
by rkang00
Thu Feb 28, 2019 1:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagrams and undissolved solids in solution
Replies: 1
Views: 22

Cell diagrams and undissolved solids in solution

How do we know when solids are undissolved in solutions but not acting as electrodes? the I2 is an example, and the 7th edition, 6L #7a is another problem too.
by rkang00
Tue Feb 26, 2019 4:54 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Porous disk of a concentration cell
Replies: 2
Views: 40

Porous disk of a concentration cell

What goes across, if anything does at all, the porous disk of a concentration cell? Do inert anions go across to the more positive side to keep the cell neutral?
by rkang00
Tue Feb 26, 2019 4:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 7th edition 6L. 3(d)
Replies: 1
Views: 23

7th edition 6L. 3(d)

Does anyone know what the half-rxns are for this problem and how to solve it?
by rkang00
Thu Feb 21, 2019 12:30 am
Forum: Balancing Redox Reactions
Topic: 6K.3 (d), 7th edition
Replies: 1
Views: 33

6K.3 (d), 7th edition

Can someone explain how to balance rxns like these with only one species on reactants or products side?
by rkang00
Mon Feb 18, 2019 4:26 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G vs. Delta G (degree sign)
Replies: 4
Views: 41

Delta G vs. Delta G (degree sign)

How is the delta G and the standard state delta G (with degree sign) differ? Is the standard state delta G constant for a specific rxn while delta G (w/o the degree) could be different?
by rkang00
Mon Feb 18, 2019 3:34 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy change: V, P, T
Replies: 4
Views: 46

Entropy change: V, P, T

How does entropy change with volume, pressure, and temperature changes? Basically: what happens to entropy if one of the three factors increases/decreases?
by rkang00
Tue Feb 12, 2019 2:50 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Internal energy (U) of an isolated system
Replies: 17
Views: 145

Internal energy (U) of an isolated system

If a system is isolated with + amount of energy, will it there be no change even after time passes?
by rkang00
Mon Feb 11, 2019 12:23 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: le chatelier's principle and continuing rxns
Replies: 2
Views: 49

le chatelier's principle and continuing rxns

It says that a way to continue a rxn without adding more reactant is to remove the product, since more reactants will be consumed to form products to minimize the effects of the loss. Isn't this an indefinite way to continue a rxn? At some point you'll run out of reactants to consume, even with Le C...
by rkang00
Thu Feb 07, 2019 12:51 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 7th edition 4F.7
Replies: 3
Views: 59

Re: 7th edition 4F.7

Then is the 5/2R and 3/2R for monoatomic ideal gases a given rule?
by rkang00
Wed Feb 06, 2019 11:26 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: 4G.5 7th edition
Replies: 1
Views: 26

4G.5 7th edition

Can someone explain how the cis and trans compounds have different orientations? cis has 12 and trans has 3, and I'm not understanding how we're supposed to obtain the number of orientations. Is it because cis has the two red atoms next to each other while the trans must have them across each other?
by rkang00
Sun Feb 03, 2019 10:16 pm
Forum: Calculating Work of Expansion
Topic: Work sign changes
Replies: 3
Views: 43

Work sign changes

Typically if a system is compressed, is the sign for work + and - for expansion?
If so, what's the reason?
by rkang00
Thu Jan 31, 2019 3:38 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A.13, 7th ed
Replies: 1
Views: 25

4A.13, 7th ed

Does anyone see an error in this problem? I don’t know where the K came from, we only had Celcius to work with.
by rkang00
Sat Jan 26, 2019 5:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Signs in bond enthalpies
Replies: 4
Views: 34

Signs in bond enthalpies

When putting signs for bond enthalpies, is it usually + on the reactants side and - on the products sign?
by rkang00
Sat Jan 26, 2019 5:21 pm
Forum: Phase Changes & Related Calculations
Topic: Phase change enthalpy signs
Replies: 2
Views: 43

Phase change enthalpy signs

For phase change enthalpies, do we have to change signs for them as well depending on which side of the rxn they're on?
by rkang00
Fri Jan 25, 2019 12:24 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: K and temp changes
Replies: 2
Views: 28

K and temp changes

I know that K changes with temperature but how does it change? Does K increase with temperature or are they inversely related? Or does it depend on case by case?
by rkang00
Thu Jan 24, 2019 4:14 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: converting between kp and kc
Replies: 4
Views: 45

converting between kp and kc

I've been seeing multiple formulas for converting kp to kc - are these just multiple forms of a single formula? Or is there a universal formula for converting kp to kc in any given problem?
by rkang00
Mon Jan 21, 2019 1:13 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak acid and its salt
Replies: 3
Views: 38

Weak acid and its salt

In a problem where we have to calculate the pH of a solution of a weak acid + its salt, do we have to take the cations into account? for example the problem in class professor Lavelle told us - the thing with nitrous acid + potassium nitrite. Do we have to take the potassium ions into account? Or do...
by rkang00
Sat Jan 19, 2019 1:43 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solving weak acid/base dissociations
Replies: 4
Views: 32

Solving weak acid/base dissociations

When we try to solve for the change in concentration (x), I guess the only way to solve it is through using the quadratic equation?
by rkang00
Thu Jan 17, 2019 2:30 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 7th Edition, 6B.9
Replies: 1
Views: 23

7th Edition, 6B.9

Does anyone know how this problem is to be done?
by rkang00
Mon Jan 14, 2019 2:06 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing Temperature
Replies: 4
Views: 64

Re: Changing Temperature

I think that's when you increase the heat of the rxn. Does anyone know what happens when the temp is lowered?
by rkang00
Sat Jan 12, 2019 5:41 pm
Forum: Ideal Gases
Topic: When to use and NOT use ideal gases?
Replies: 1
Views: 34

When to use and NOT use ideal gases?

Is there a place to not use the ideal gas formula? I heard somewhere that ideal gases may not apply to every case.
by rkang00
Thu Jan 10, 2019 3:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc, Kp, K
Replies: 3
Views: 37

Kc, Kp, K

What’s the difference between K, Kc, and Kp? The textbook seems like it’s considering K and Kp one and the same.
Also, what does the C in Kc mean?
by rkang00
Wed Dec 05, 2018 4:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing power precedence
Replies: 1
Views: 45

Polarizing power precedence

I know for cations of the same row we compare charge and same column we compare atomic radii, but if we're comparing cations of different rows and columns which takes precedence over the other? I had this part of the test wrong.
by rkang00
Tue Dec 04, 2018 11:37 pm
Forum: Naming
Topic: Water as a ligand
Replies: 5
Views: 86

Re: Water as a ligand

What about in formulas? I'm not sure when to use H2O or OH2.
by rkang00
Tue Dec 04, 2018 11:05 pm
Forum: Naming
Topic: Water as a ligand
Replies: 5
Views: 86

Water as a ligand

If water is a ligand, how do we write it? There seems to be two ways of writing it: H2O and OH2, but I'm not clear on which style applies to which scenario.
by rkang00
Tue Dec 04, 2018 11:01 pm
Forum: Naming
Topic: Anionic ligands
Replies: 5
Views: 67

Anionic ligands

It says in the textbook that anionic ligands that end in -ide, -ate, -ite change their endings to -ido, -ato, ito respectively. I don't think this was covered in class; is this something different? When do we use this for?
by rkang00
Sun Dec 02, 2018 9:35 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs Lewis
Replies: 4
Views: 72

Re: Bronsted vs Lewis

Then can an acid/base be considered Bronsted AND Lewis at the same time?
by rkang00
Sun Dec 02, 2018 12:45 am
Forum: Sigma & Pi Bonds
Topic: Sigma/pi bond: orbitals
Replies: 1
Views: 59

Sigma/pi bond: orbitals

When forming pi or sigma bonds, does it matter which orbitals are used? As in, can only an s & p orbital form sigma and p&p form pi bonds? (it's just a theoretical example)
by rkang00
Sat Dec 01, 2018 7:57 pm
Forum: Dipole Moments
Topic: Dipole moments and resonances
Replies: 3
Views: 59

Dipole moments and resonances

If a molecule's dipole moments cancel out, does this mean that structures with resonance have no net dipole movement? I think that was the case for neutral sulfite (SO3); it has resonance but the real molecule in reality has the bond length equal to the average of the bond lengths of the resonance s...
by rkang00
Sat Dec 01, 2018 7:19 pm
Forum: Naming
Topic: Spaces in naming
Replies: 2
Views: 59

Spaces in naming

The lecture notes tell us that there's usually no spacing when naming coordination compounds. Does this mean that writing with spaces in a test will result in loss of points? Also, we add an O to the end of an anion only if it's within the coordination sphere, right?
by rkang00
Tue Nov 27, 2018 9:54 pm
Forum: Resonance Structures
Topic: Bond lengths & number of resonance structures
Replies: 3
Views: 75

Bond lengths & number of resonance structures

How does the number of resonance structures determine bond length? Do we end up having more bond lengths to average out?
by rkang00
Sat Nov 24, 2018 10:54 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw bond angles
Replies: 3
Views: 74

Seesaw bond angles

How many bond angles in a seesaw-shaped structure are 90 degrees wide? I know the structure has both 90 and 120 degree angles but I'm not sure of how many of each are there.
by rkang00
Sat Nov 24, 2018 10:44 am
Forum: Sigma & Pi Bonds
Topic: sigma/pi bonds and resonance
Replies: 1
Views: 41

sigma/pi bonds and resonance

If a test asks us to find the number sigma and pi bonds of a molecule that has a resonance structure I assume we have to find the numbers of bonds for each structure to get full credit?
by rkang00
Thu Nov 22, 2018 2:20 pm
Forum: Administrative Questions and Class Announcements
Topic: 14B and 14BL finals
Replies: 3
Views: 80

14B and 14BL finals

Is taking 14B and 14BL finals on the same day doable? I'm just asking out of curiosity, please let me know!
by rkang00
Tue Nov 20, 2018 11:06 pm
Forum: Hybridization
Topic: s-character [ENDORSED]
Replies: 1
Views: 51

s-character [ENDORSED]

On 7th edition, 2F.15 there's a question about s-character. What's s-character of the hybrid orbitals? Apparently it affects bond angles.
by rkang00
Sat Nov 17, 2018 12:53 pm
Forum: Dipole Moments
Topic: sigma, pi bonds rotation
Replies: 2
Views: 47

sigma, pi bonds rotation

How does a sigma or pi bond being able to/unable to rotate influence bonding? Why is it important to note?
by rkang00
Sat Nov 17, 2018 12:42 pm
Forum: Dipole Moments
Topic: Polarity and dipole moment
Replies: 4
Views: 93

Polarity and dipole moment

If dipole moments that cancel each other result in nonpolarity does this mean that symmetric atoms and molecules are generally nonpolar?
by rkang00
Thu Nov 15, 2018 1:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR forms
Replies: 3
Views: 52

VSEPR forms

Are VSEPR shapes formed so that there's maximum repulsion between atoms?
by rkang00
Sun Nov 11, 2018 9:30 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: Bond energy value signs
Replies: 3
Views: 92

Bond energy value signs

Why are the bond energy signs all negative? They're all attractive forces that result from subtraction but I don't get why they're results of subtraction and why they're negative.
by rkang00
Tue Nov 06, 2018 8:48 pm
Forum: Lewis Structures
Topic: expanded octet
Replies: 2
Views: 59

expanded octet

How do you know that an atom has only one additional bond in addition to an octet? is the number of remaining orbitals the way to determine it? (take bromate for example - how do you know it's just 5 bonds on bromine and not 6)
by rkang00
Tue Nov 06, 2018 7:51 pm
Forum: Resonance Structures
Topic: bond lengths of resonant atoms
Replies: 4
Views: 117

bond lengths of resonant atoms

How are the bond lengths of resonant atoms (nitrate, nitrite) the same when the resonant structures have different bond lengths?
by rkang00
Sat Nov 03, 2018 12:39 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Test Question 1a
Replies: 2
Views: 112

Re: Test Question 1a

Wait, so we have to get the mass of each molecule separately b/c the mass of N2 (14.0067x2) is the molar mass, not the mass of the individual N2 molecule? I also got that question wrong, so I was confused about it
by rkang00
Fri Nov 02, 2018 1:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Filling of Orbitals
Replies: 3
Views: 107

Re: Filling of Orbitals

So we just have to follow the periodic table in numerical order? That's not what I remembered - or did I hear something wrong?
by rkang00
Fri Nov 02, 2018 1:12 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Is electron removed from 3d or 4s first?
Replies: 5
Views: 350

Re: Is electron removed from 3d or 4s first?

Does this mean that generally 4s orbitals will lose electrons before 3d electrons are lost?
by rkang00
Fri Oct 26, 2018 6:48 pm
Forum: Trends in The Periodic Table
Topic: Isoelectronic atoms sizes [ENDORSED]
Replies: 3
Views: 74

Isoelectronic atoms sizes [ENDORSED]

How would the size of isoelectronic atoms compare? for example which would be bigger: Ne or Na+? Would this be dependent on nuclear charge?
by rkang00
Fri Oct 26, 2018 6:42 pm
Forum: *Particle in a Box
Topic: Application
Replies: 3
Views: 283

Re: Application

Okay but when do you use the equation for? I never fully understood where to use it (if anyone knows if it explains in the textbook let me know)
by rkang00
Wed Oct 24, 2018 2:00 am
Forum: DeBroglie Equation
Topic: De Broglie wavelengths
Replies: 3
Views: 103

De Broglie wavelengths

Are De Broglie wavelengths used for large particles? How do we know when to use the De Broglie equation to get a wavelength? It's confusing when to use the De Broglie or the E=hv equation.
by rkang00
Thu Oct 18, 2018 6:44 pm
Forum: *Shrodinger Equation
Topic: d orbital
Replies: 1
Views: 55

d orbital

For one of the d-orbitals (I think dx) why was the orbital a ring again? The rest are in cones so I don't get why dx is a ring
by rkang00
Thu Oct 18, 2018 6:07 pm
Forum: *Shrodinger Equation
Topic: x,y,z notation in schrodinger's equaton
Replies: 2
Views: 73

Re: x,y,z notation in schrodinger's equaton

It might have to do with the principal quantum number and orbital number. There's another number that I can't recall right now but they're in the textbook - the notations are n, l, ml.
by rkang00
Thu Oct 18, 2018 5:56 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Formula
Replies: 4
Views: 89

Re: Bohr Formula

Why do we have to add a negative sign though? is it just an indication of a difference in energy levels?
by rkang00
Mon Oct 15, 2018 12:39 am
Forum: Einstein Equation
Topic: Kinetic energy and e = hv
Replies: 3
Views: 93

Kinetic energy and e = hv

If an electron is ejected with zero kinetic energy, what would it look like in real life? How would the electron actually move? Also, if kinetic energy is zero I guess this means that the work function (threshold energy) and hv are equal to each other?
by rkang00
Thu Oct 11, 2018 1:22 am
Forum: Photoelectric Effect
Topic: Work function
Replies: 7
Views: 101

Work function

In the lecture, there's a constant reference to 'work function'. What is that, is that the threshold energy with a circle-with-a-line-through-it as a symbol?
by rkang00
Thu Oct 11, 2018 1:20 am
Forum: Einstein Equation
Topic: Spectroscopy experimenting
Replies: 4
Views: 115

Spectroscopy experimenting

in a spectroscopy experiment, there are three components: E = hv, work function, and Ek. If the electron has no kinetic energy, does it mean that the electron is detached but doesn't move? How would it look like in real life?
by rkang00
Sun Oct 07, 2018 9:00 pm
Forum: Significant Figures
Topic: Calculating process
Replies: 5
Views: 200

Calculating process

Ok so let's say the figures given in a problem are 250.0ml, .0350M, 33g. So would the final answer have to be in 2 sig figs, but we don't round during calculations?
by rkang00
Thu Oct 04, 2018 6:57 pm
Forum: SI Units, Unit Conversions
Topic: HW E9 in textbook
Replies: 3
Views: 54

HW E9 in textbook

Can molecules be calculated in moles as well? I thought moles only applied to atoms - or am I mistaken?
by rkang00
Tue Oct 02, 2018 5:50 pm
Forum: Molarity, Solutions, Dilutions
Topic: Titrations v Dilutions
Replies: 2
Views: 61

Titrations v Dilutions

Just wondering, what's the difference between titrations and dilutions? I swear I learned it in high school but I just can't remember - I often get confused between the two.

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