Search found 88 matches

by Cole Elsner 2J
Wed Mar 13, 2019 3:13 pm
Forum: Second Order Reactions
Topic: Units
Replies: 4
Views: 79

Re: Units

In total the rate should be in M/s, but k will have units of 1/M*s
by Cole Elsner 2J
Wed Mar 13, 2019 3:12 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Molecularity
Replies: 2
Views: 164

Re: Molecularity

Think of the order of the reaction when determining molecularity.
by Cole Elsner 2J
Wed Mar 13, 2019 3:11 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E˚ vs E
Replies: 13
Views: 245

Re: E˚ vs E

E* refers to cell potential at standard conditions, it does NOT change with amount of substance. E is just the potential of the cell under ANY conditions.
by Cole Elsner 2J
Mon Mar 11, 2019 12:42 pm
Forum: Zero Order Reactions
Topic: Zero Order Reaction
Replies: 5
Views: 200

Re: Zero Order Reaction

An example I like to think of is having to reactants, A and B, and a few different experiments changing the concentrations of each, and analyzing the change in the rate. When A is increased, let's say that the reaction shows no change. You do the same for B, still no change. I think of zero order as...
by Cole Elsner 2J
Wed Mar 06, 2019 8:51 pm
Forum: First Order Reactions
Topic: Units
Replies: 3
Views: 75

Re: Units

Your end goal is to have all units b in M/s. With this, you can figure out what the order of the reaction is and adjust k units to reach that end goal units.
by Cole Elsner 2J
Wed Mar 06, 2019 12:06 pm
Forum: Van't Hoff Equation
Topic: Temp Units
Replies: 11
Views: 316

Re: Temp Units

It would be in K. Think about the units for R! They all need to cancel out
by Cole Elsner 2J
Tue Mar 05, 2019 10:23 am
Forum: General Rate Laws
Topic: Order Reaction/Rate Law
Replies: 3
Views: 52

Re: Order Reaction/Rate Law

Use the rate law, and add up the exponents of each reactant.
by Cole Elsner 2J
Mon Mar 04, 2019 10:25 pm
Forum: First Order Reactions
Topic: Half life first order reaction rate
Replies: 1
Views: 52

Re: Half life first order reaction rate

We haven't really been taught this yet. We JUST finished our first order work, so we should wait for Dr. Lavelle to actually cover this in lecture.
by Cole Elsner 2J
Mon Mar 04, 2019 10:23 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 9 HW
Replies: 6
Views: 123

Re: Week 9 HW

Just stick with kinetics. I do recommend practicing the electrochem problems not included on the test just to stay sharp.
by Cole Elsner 2J
Mon Mar 04, 2019 10:22 pm
Forum: General Rate Laws
Topic: Units of Rate Constant
Replies: 4
Views: 79

Re: Units of Rate Constant

In a zero order reaction, the rate constant would just be M*s^-1. With a first order reaction, we'd have just s^-1, as we'd have M from our reactant. In second order we have M^-1*s^-1, and from every unit jump forwards, we have a higher number of M, which is just our order # - 1.
by Cole Elsner 2J
Mon Feb 25, 2019 10:26 pm
Forum: Balancing Redox Reactions
Topic: Gibbs free energy
Replies: 1
Views: 41

Re: Gibbs free energy

If you look over some of the equations in your constants and equations sheet, you can see some overlap with dGnought and dEnought. With these equations you can mix and match in other equations in terms of one or the other.
by Cole Elsner 2J
Mon Feb 25, 2019 10:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: MnO4-
Replies: 1
Views: 27

Re: MnO4-

O has a charge of -2, so for of those is 8- charge total. Because the combination of Mn and O4 is -, Mn must be 7+ so when those charges are added together it matches what's given.
by Cole Elsner 2J
Mon Feb 25, 2019 7:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Question 6N.1 B 7th Edition
Replies: 1
Views: 53

Question 6N.1 B 7th Edition

Does the solutions manual have an error for this problem? It states that the half reaction for In3+ to In2+ is
In3+ + 2e- --> In2+
This causes the Nernst Equation to use 2 for n, when it should just be one right?
by Cole Elsner 2J
Mon Feb 25, 2019 6:12 pm
Forum: Balancing Redox Reactions
Topic: Friday Lecture Example [ENDORSED]
Replies: 2
Views: 75

Re: Friday Lecture Example [ENDORSED]

Also, Fe has no phase change, so Pt is necessary as a solid electrode in the diagram cathode side.
by Cole Elsner 2J
Mon Feb 25, 2019 6:03 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n value
Replies: 11
Views: 134

Re: n value

I believe n can be the change of moles in the equation or the number of electrons transferred.
by Cole Elsner 2J
Sun Feb 24, 2019 9:35 pm
Forum: Balancing Redox Reactions
Topic: Salt Bridges-won't they dissolve?
Replies: 5
Views: 90

Re: Salt Bridges-won't they dissolve?

The salt bridge isn't actually made up of salt itself. It's tubing with gel inside to provide electrical contact between the anode and the cathode.
by Cole Elsner 2J
Sun Feb 24, 2019 9:33 pm
Forum: Balancing Redox Reactions
Topic: Mnemonic for Redox
Replies: 5
Views: 85

Re: Mnemonic for Redox

Are you thinking about LEO and GER?

Lose Electron Oxidation

Gain Electron Reduction?
by Cole Elsner 2J
Fri Feb 22, 2019 12:05 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G = 0
Replies: 4
Views: 72

Re: Delta G = 0

Reaction is at physical equilibrium, generally =0 at phase changes!
by Cole Elsner 2J
Wed Feb 20, 2019 8:18 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs concept
Replies: 7
Views: 137

Re: Gibbs concept

Danny Elias Dis 1E wrote:Can someone explain what is happening on a physical level when deltaG = 0 (the Gibbs free energy is at equilibrium)?

The reaction is at physical equilibrium, and most likely going through a phase change.
by Cole Elsner 2J
Tue Feb 19, 2019 3:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: What to do when temperature isn't given
Replies: 8
Views: 136

Re: What to do when temperature isn't given

If it's stated to be in standard conditions. If a temperature is given, use that.
by Cole Elsner 2J
Tue Feb 19, 2019 12:57 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G a state function?
Replies: 23
Views: 325

Re: Delta G a state function?

Aidan Ryan 1B wrote:What are things we have learned that are not state functions?


Work is NOT a state function because it depends on the path taken to get to the final result.
by Cole Elsner 2J
Tue Feb 19, 2019 12:56 pm
Forum: General Rate Laws
Topic: test 3
Replies: 6
Views: 140

Re: test 3

"Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7). Test 2 starts Tuesday of Week 8."

Word for word from website. This will 100% be what we're tested on
by Cole Elsner 2J
Mon Feb 18, 2019 4:53 pm
Forum: Van't Hoff Equation
Topic: Concept behind Van't Hoff Equation
Replies: 5
Views: 94

Re: Concept behind Van't Hoff Equation

This equation helps us determine how a system behaves at equilibrium at a new temperature. The value of K itself changes, so you can really see if products or reactants are favored more or less than they were before!
by Cole Elsner 2J
Mon Feb 18, 2019 4:50 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G vs. Delta G (degree sign)
Replies: 4
Views: 139

Re: Delta G vs. Delta G (degree sign)

It's just the difference between standard conditions and specific conditions for a system.
by Cole Elsner 2J
Mon Feb 18, 2019 4:47 pm
Forum: Calculating Work of Expansion
Topic: Units for R
Replies: 10
Views: 330

Re: Units for R

These units vary. Always write out your units for calculations, just so you know what R value is needed to solve. In order to get the write answer you need to use the correct R based off of what's asked for and what units are given.
by Cole Elsner 2J
Mon Feb 18, 2019 4:46 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Calculating Gibbs Free Energy Equations
Replies: 2
Views: 57

Re: Calculating Gibbs Free Energy Equations

Both of these methods work! In the end it's all a state function so your path is up to you. With these problems just try to make the most out of what's GIVEN to you.
by Cole Elsner 2J
Wed Feb 13, 2019 8:59 pm
Forum: Phase Changes & Related Calculations
Topic: ΔH vs ΔU?
Replies: 8
Views: 350

Re: ΔH vs ΔU?

Yes at constant pressure. If there is no net change in moles, there will be no work done. So there is the potential for deltaU=deltaH.
by Cole Elsner 2J
Wed Feb 13, 2019 8:58 pm
Forum: General Science Questions
Topic: Midterm Formulas
Replies: 6
Views: 383

Re: Midterm Formulas

Everything on the constants and equations sheet will be provided. I don't think EVERY formula is on that, so be sure to know them all.
by Cole Elsner 2J
Mon Feb 11, 2019 12:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpies
Replies: 10
Views: 161

Re: Bond enthalpies

Lewis structures ARE helpful for figuring out exactly what is being broken, but it is still possible to solve these problems just by looking at the differences between the reactants and products side.
by Cole Elsner 2J
Mon Feb 11, 2019 12:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 5
Views: 110

Re: Hess's Law

The test will most likely provide these reactions, but I think knowing the general format of a combustion reaction could come in handy!
by Cole Elsner 2J
Mon Feb 11, 2019 12:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework during midterm week [ENDORSED]
Replies: 5
Views: 108

Re: Homework during midterm week [ENDORSED]

I recommend doing any thermodynamic problems, as that's what was most recently covered.
by Cole Elsner 2J
Wed Feb 06, 2019 6:00 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Degenerate states and volume
Replies: 1
Views: 30

Re: Degenerate states and volume

Because there was a certain amount of degenerate states in the initial volume, doubling said volume would double the positions molecules can take. Because there's more volume, there's more space/positions to fill, in fact, it's DOUBLE.
by Cole Elsner 2J
Wed Feb 06, 2019 5:56 pm
Forum: Calculating Work of Expansion
Topic: Integral Expression for Work
Replies: 4
Views: 91

Re: Integral Expression for Work

The integral equation applies to reversible work, where P is not a constant. Use it if stated to be reversible. Use w=-PdeltaV if it's irreversible.
by Cole Elsner 2J
Wed Feb 06, 2019 5:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Do we have discussion on the day of the midterm?
Replies: 2
Views: 65

Re: Do we have discussion on the day of the midterm?

I believe the schedule carries out as normal, unless there's a conflict of timing.
by Cole Elsner 2J
Tue Feb 05, 2019 11:27 am
Forum: Calculating Work of Expansion
Topic: Work vs Degeneracy
Replies: 2
Views: 58

Re: Work vs Degeneracy

Work is a lower case w and degeneracy is a capital W. They appear to be separate from each other, and not have much influence on one another. (I may be wrong about that, but w and W are still different)
by Cole Elsner 2J
Tue Feb 05, 2019 11:19 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 2
Views: 59

Re: Entropy

Delta U and delta H do not fully describe the system without entropy. Entropy is the likelihood (probability) a system will be in a particular start. The combination of delta U delta h and entropy can give more information as to how the system will change.
by Cole Elsner 2J
Wed Jan 30, 2019 7:28 pm
Forum: Calculating Work of Expansion
Topic: 4A.3 7th Ed
Replies: 6
Views: 89

Re: 4A.3 7th Ed

I believe we'll learn how to do this in an upcoming lecture. Don't stress yourself out over it just yet! I'm certain we'll be taught how to do this, if not the book and chemistry community will surely help!
by Cole Elsner 2J
Tue Jan 29, 2019 10:59 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity
Replies: 5
Views: 94

Re: Heat Capacity

This honestly depends on the question being asked. Given units and a period table, you should be able to know whether to convert or not to match the question. Just read carefully and fully understand what's being asked for and how you will get there.
by Cole Elsner 2J
Tue Jan 29, 2019 10:57 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 7
Views: 89

Re: Bond Enthalpies

Diatomic bond enthalpies tend to be accurate, however every other molecule/bond in a chemical reaction has bond enthalpies made up of an average of thousands of different measurements. This averaging makes it inaccurate.
by Cole Elsner 2J
Mon Jan 28, 2019 10:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Breaking Bonds
Replies: 4
Views: 73

Re: Breaking Bonds

I recommend drawing all lewis structures out and observe what has changed. Visually seeing it helps a lot.
by Cole Elsner 2J
Mon Jan 28, 2019 10:50 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cv and Cp
Replies: 3
Views: 74

Re: Cv and Cp

It will most likely be made clear whether or not it's constant pressure or constant volume. I believe the type of calorimeter will be said two, so know how to distinguish them.
by Cole Elsner 2J
Fri Jan 25, 2019 6:02 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Seventh Edition ? 4A.9
Replies: 1
Views: 30

Re: Seventh Edition ? 4A.9

I don't think we learned this in class yet. Would be best to not stress and put it aside until we're taught what to do.
by Cole Elsner 2J
Tue Jan 22, 2019 2:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: PH of Weak Acids and Bases
Replies: 1
Views: 49

PH of Weak Acids and Bases

I recall in lecture that a problem arises when calculating PH for a small amount of a weak acid that's smaller than 10^-7. I was wondering what I should do if this ever happens. Thanks!
by Cole Elsner 2J
Tue Jan 22, 2019 2:26 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Conceptual questions
Replies: 6
Views: 123

Re: Conceptual questions

Maybe review autoprotolysis and ATP hydrolysis as well. These were 2 things included in lecture that may be important or asked about.
by Cole Elsner 2J
Tue Jan 22, 2019 2:22 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Sig Figs of pKa
Replies: 2
Views: 373

Re: Sig Figs of pKa

This applies to pKa and pKb as well because a log is being taken. If you try to use 10^-pKa/b, you will not get the concentration you initially had, so this rule remains.
by Cole Elsner 2J
Wed Jan 16, 2019 7:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: partial pressure v concentration
Replies: 4
Views: 66

Re: partial pressure v concentration

I believe partial pressure can only be used for homogeneous gaseous reactions. Using Kp and Kc also depends of what information you've been given, like whether or not the problem lists things in M or atm.
by Cole Elsner 2J
Tue Jan 15, 2019 11:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE charts
Replies: 3
Views: 55

Re: ICE charts

I believe ICE charts only take concentrations. Like mol/L or partial pressures for gasses.
by Cole Elsner 2J
Tue Jan 15, 2019 11:17 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Equilibrium values
Replies: 2
Views: 43

Re: Calculating Equilibrium values

If there are concentrations of both products and reactants, try to figure out Q and determine if the reaction needs to go to the left or the right. This is so you know whether or not to subtract x or add x to both sides. If only given one initial concentration on one side, assume x is subtracted fro...
by Cole Elsner 2J
Mon Jan 14, 2019 2:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 7th Edition 5H 3
Replies: 2
Views: 37

7th Edition 5H 3

I'm a bit confused as to how I can calculate K for the combination of 2 reactions on table 5G.2. This question asks for the value of K at 300 K for
2BrCl+H2 <-->Br2 +HCl. I don't believe this was taught in lecture, but it is on outline 1 so I'm looking for some tips.

Thanks!
by Cole Elsner 2J
Mon Jan 07, 2019 7:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Topic 5G.9 7th Edition HW Problem
Replies: 2
Views: 52

Re: Topic 5G.9 7th Edition HW Problem

Both reactions occur under the same conditions, just with a different amount of O3 to begin with. More of this reactant will produce more of the product, but both reactions will have the SAME equilibrium constants. Because the concentration (or pressure) of O3 increases in the second experiment, the...
by Cole Elsner 2J
Mon Jan 07, 2019 7:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium vs Initial
Replies: 2
Views: 36

Re: Equilibrium vs Initial

I believe that equilibrium concentrations should be used when solving for K. In our lecture examples that's what we used, the concentrations of molecules at equilibrium.
by Cole Elsner 2J
Mon Jan 07, 2019 7:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Video Module Post Assessment Question 12
Replies: 3
Views: 58

Video Module Post Assessment Question 12

For this question I put that "The forward reaction rate is the same as the reverse reaction rate" was false, but it was marked wrong.
I thought the reverse reaction rate was 1/Kc, so I'm confused as to why this was incorrect. Thanks!
by Cole Elsner 2J
Sat Dec 08, 2018 12:02 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: H20 as ligand
Replies: 1
Views: 49

Re: H20 as ligand

It does have two lone pairs, but only one of them can attach to a center atom instead of a both. Because only oxygen attaches with one of its lone pairs, it's monodentate.
by Cole Elsner 2J
Thu Dec 06, 2018 7:53 pm
Forum: Lewis Structures
Topic: Lewis structure of SO2
Replies: 1
Views: 59

Re: Lewis structure of SO2

Sulfur can have more than an octet, as added electrons can "fill" the 3d orbital. I think both structures are correct, but SO2 with 2 double bonds is more stable, as all atoms have a formal charge of 0.
by Cole Elsner 2J
Wed Dec 05, 2018 6:52 pm
Forum: Naming
Topic: Water as a ligand
Replies: 5
Views: 144

Re: Water as a ligand

OH2 and H2O are the same! Oxygen has the lone pairs, so that's where the coordinate covalent bond forms in every situation. Some put O first to show Oxygen is the bonding site, however both OH2 and H2O are the same thing
by Cole Elsner 2J
Tue Dec 04, 2018 12:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Naming on the Final
Replies: 4
Views: 161

Re: Naming on the Final

Typically more complex acids/bases will have names and formulas provided, but it's always nice to know more common ones and review the table in the book, just to stay sharp.
by Cole Elsner 2J
Mon Dec 03, 2018 6:40 pm
Forum: Naming
Topic: 9C.3 7th edition
Replies: 1
Views: 43

Re: 9C.3 7th edition

The formulas don't have a charge because the combination of K3 and [Cr(CN)6] combine with no net charge

I don't think order matters much when writing in the brackets, as long as your anions are correct. However, order does matter when naming!
by Cole Elsner 2J
Mon Nov 26, 2018 7:58 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 4
Views: 109

Re: Polarizability

AlyssaBei_1B wrote:For polarizability, would the trend decrease across a period from right to left because the atoms are getting smaller from right to left?


Yes, polarizablity follows the same trends as atomic radii.
by Cole Elsner 2J
Mon Nov 26, 2018 7:54 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 5
Views: 115

Re: Polarizability

The trend in polarizability is similar to the trend of atomic radii. Decreases to the right and increases down the periodic table.
by Cole Elsner 2J
Mon Nov 26, 2018 7:51 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: CN- v O2 stability
Replies: 2
Views: 69

Re: CN- v O2 stability

CN- has a triple bond, so it's bond is shorter and stronger than the double bond in O2
by Cole Elsner 2J
Mon Nov 26, 2018 7:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Dipole Moment
Replies: 3
Views: 93

Re: Dipole Moment

The arrow points towards the more electronegative element. This element has a delta negative, as it's where the dipole moment goes.
by Cole Elsner 2J
Fri Nov 23, 2018 4:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing Structures on Test
Replies: 11
Views: 190

Re: Drawing Structures on Test

Just know how to draw the lewis structure and name the shape based off of electron densities, bonds, and lone pairs. Wedges just help with visualization.
by Cole Elsner 2J
Fri Nov 23, 2018 4:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework for week 9
Replies: 11
Views: 258

Re: Homework for week 9

As long as you do the work and have it all together, you should be fine.
by Cole Elsner 2J
Fri Nov 23, 2018 4:45 pm
Forum: Hybridization
Topic: when to use hybridization
Replies: 4
Views: 97

Re: when to use hybridization

Hybridization will most likely be asked. Just know how to mix your valence electrons to understand the concept itself.
by Cole Elsner 2J
Fri Nov 23, 2018 4:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 7
Views: 120

Re: Polarity

Dipole moments go towards the more electronegative element in a molecule. To determine polarity, consider the shape of the molecule itself. Take into account the arrows, where they're going, if they cancel out, or if they're different atoms. If everything cancels out, it's nonpolar, but if it's even...
by Cole Elsner 2J
Wed Nov 14, 2018 6:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electrons and VSEPR
Replies: 4
Views: 73

Re: Electrons and VSEPR

Lone Pairs do influence shape, they are still an area of electron concentration, and should be taken into consideration instead of being omitted.
by Cole Elsner 2J
Tue Nov 13, 2018 6:38 pm
Forum: Ionic & Covalent Bonds
Topic: delta positive delta negative
Replies: 15
Views: 363

Re: delta positive delta negative

Draw everything out first, then find the most electronegative atom (remember trends on the periodic table). This atom becomes delta negative, as it is an acceptor, and the other atom is delta positive.
by Cole Elsner 2J
Tue Nov 13, 2018 6:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 8
Views: 143

Re: Bond Angles

We weren't taught any set formula to calculate any bond angles. I believe the only way for us to really have an idea of what the angle may be is to memorize the shape of a molecule and what bond angles it yields.
by Cole Elsner 2J
Mon Nov 05, 2018 1:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Alternative version of formula
Replies: 7
Views: 359

Re: Alternative version of formula

Yes it works, use whatever formula you're most comfortable with, but understand what the formula presented means.
by Cole Elsner 2J
Mon Nov 05, 2018 1:49 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charges in charged molecules
Replies: 5
Views: 93

Re: Formal charges in charged molecules

Just carry out the process of drawing the lewis structure and finding formal charge. At the end of it all once it's balanced you'll be able to figure it out
by Cole Elsner 2J
Mon Nov 05, 2018 1:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Calculator for Midterm
Replies: 2
Views: 97

Re: Calculator for Midterm

yes, as long as it isn't a graphing calculator
by Cole Elsner 2J
Mon Oct 29, 2018 5:09 pm
Forum: Einstein Equation
Topic: E=hv
Replies: 41
Views: 1405

Re: E=hv

E represents the energy of the photon. h is Plancks's Constant (6.63*10^-34) and v is the calculated or measured frequency of a light source (typically UV or above for these equations)
by Cole Elsner 2J
Mon Oct 29, 2018 5:05 pm
Forum: Lewis Structures
Topic: lewis structure
Replies: 10
Views: 288

Re: lewis structure

Typically the atom with the lowest ionization energy ends up in the middle for lewis structure. Remember, ionization energy increases from going up and to the right of the periodic table.
by Cole Elsner 2J
Mon Oct 29, 2018 5:00 pm
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 3
Views: 112

Re: Bond Lengths

They're just the results that he found. There's no specific way we need to know to find these, they're just examples of bond lengths to put things into perspective.
by Cole Elsner 2J
Wed Oct 24, 2018 7:00 pm
Forum: Trends in The Periodic Table
Topic: Seventh Edition 1F.11 C
Replies: 1
Views: 107

Seventh Edition 1F.11 C

I'm a little confused about part C of question 11. For the other answer choices in the same column, their electron affinities are equal. However, for oxygen and sulfur, sulfur has a higher affinity. Why is this so?

Thanks
by Cole Elsner 2J
Mon Oct 22, 2018 9:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 2
Views: 124

Re: Test 2

Even if the test isn't concept heavy, it is useful to have a deep understanding of concepts. When you perform all your calculations, you can really understand what they mean and kind of predict what the answer will look like.
by Cole Elsner 2J
Mon Oct 22, 2018 9:45 pm
Forum: Quantum Numbers and The H-Atom
Topic: Question 1E.7 B Seventh Edition
Replies: 1
Views: 52

Question 1E.7 B Seventh Edition

For part B of question 1E7, the electron configuration for nitrogen is considered to be excited. Is it because 2py is a down spin? I'm a little lost. Thanks!
by Cole Elsner 2J
Mon Oct 22, 2018 9:32 pm
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 28781

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]

These really help me out a lot! Practice makes perfect, the more to do the better. Thanks!
by Cole Elsner 2J
Tue Oct 16, 2018 6:40 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals problem 1E.11
Replies: 2
Views: 40

Re: Orbitals problem 1E.11

I would recommend waiting until we learn about orbitals in lecture. There's a lot of unnecessary stress involved trying to do problems that haven't been taught yet. For now just practice what we know, and when the time is right, practice orbitals!
by Cole Elsner 2J
Tue Oct 16, 2018 6:35 pm
Forum: *Particle in a Box
Topic: Hw assignment?
Replies: 7
Views: 429

Re: Hw assignment?

We're still in the quantum section. It's nice trying to get ahead and understanding things in advance,but I would recommend doing problems pertaining to what is currently being taught in class. This could save you some time and reduce stress!
by Cole Elsner 2J
Tue Oct 16, 2018 6:32 pm
Forum: DeBroglie Equation
Topic: Mass of electrons
Replies: 3
Views: 78

Re: Mass of electrons

It will be given, but it's always helpful to know the mass of an electron is 9.11*10^-31 off the top of your head! It could save some time during tests so you wouldn't have to search for it!
by Cole Elsner 2J
Fri Oct 12, 2018 11:01 am
Forum: Einstein Equation
Topic: Symbol for frequency
Replies: 12
Views: 246

Re: Symbol for frequency

v is used in both lectures and the textbook, so it's probably the safest symbol to use.
by Cole Elsner 2J
Tue Oct 09, 2018 6:04 pm
Forum: Photoelectric Effect
Topic: Vacuum
Replies: 4
Views: 122

Re: Vacuum

In the experiment, a detector is used. If it is not performed in a vacuum, then air molecules may get analyzed by the detector and interfere with the process. There is also the risk of air molecules interacting with the electrons in the experiment.
by Cole Elsner 2J
Mon Oct 08, 2018 2:32 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Question 1A.15, Seventh Edition Page 10
Replies: 1
Views: 31

Homework Question 1A.15, Seventh Edition Page 10

This questions observes a line of 102.6nm on the hydrogen spectrum. It then asks to determine the values of n for initial and final energy levels of the electron that lead to this line. Any tips for how to start?

Thanks!
by Cole Elsner 2J
Mon Oct 08, 2018 2:12 pm
Forum: Properties of Light
Topic: Homework Question 1A.3 C, Seventh Edition Page 9
Replies: 1
Views: 50

Homework Question 1A.3 C, Seventh Edition Page 9

Question 1A.3 asks to clarify what happens when the frequency of electromagnetic radiation decreases. It's basically true of false with explanation. The part of the question that confused me was part C, which states: "The extent of the change in the electrical field at a given point decreases.&...
by Cole Elsner 2J
Tue Oct 02, 2018 7:15 pm
Forum: Balancing Chemical Reactions
Topic: Problem L.35
Replies: 5
Views: 86

Re: Problem L.35

The solutions manual has Fe3Br8 listed. That's the only way it works out. I guess it's a typo in the Seventh edition :/
by Cole Elsner 2J
Tue Oct 02, 2018 2:58 pm
Forum: SI Units, Unit Conversions
Topic: State Symbols
Replies: 2
Views: 84

State Symbols

Is it mandatory to include state symbols (s, l, aq, g) when writing out chemical equations? I was just wondering.

Thanks!
by Cole Elsner 2J
Mon Oct 01, 2018 5:23 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Question E.9: Epsom Salts
Replies: 2
Views: 111

Question E.9: Epsom Salts

Any advice for writing formulas based off of a given name? In this case, how would one write out Magnesium Sulfate Heptahydrate?

Thanks!

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