Search found 51 matches

by Michael Lee 2I
Fri Mar 16, 2018 2:48 am
Forum: General Rate Laws
Topic: Units
Replies: 11
Views: 578

Re: Units

Just make sure all of your units are consistent.
by Michael Lee 2I
Fri Mar 16, 2018 2:46 am
Forum: First Order Reactions
Topic: Help on 15.3
Replies: 7
Views: 388

Re: Help on 15.3

The units of k are always mol * L/s
by Michael Lee 2I
Fri Mar 16, 2018 2:46 am
Forum: First Order Reactions
Topic: Help on 15.3
Replies: 7
Views: 388

Re: Help on 15.3

The units of k are always mol * L/s
by Michael Lee 2I
Fri Mar 16, 2018 2:45 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius equation and order of rxn
Replies: 3
Views: 155

Re: Arrhenius equation and order of rxn

It technically can be used for all orders because order does not play a part in the equation.
by Michael Lee 2I
Fri Mar 16, 2018 2:43 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.49
Replies: 2
Views: 108

Re: 15.49

Intermediates are not included in the overall rate law.
by Michael Lee 2I
Sat Mar 10, 2018 12:40 am
Forum: Zero Order Reactions
Topic: Zero order
Replies: 5
Views: 640

Re: Zero order

If a zero order is in the reaction, the rate law is k[A]^0 = k. Therefore it has is not based on the concentration, only the rate constant.
by Michael Lee 2I
Sat Mar 10, 2018 12:38 am
Forum: Second Order Reactions
Topic: 3rd order?
Replies: 7
Views: 583

Re: 3rd order?

I agree
by Michael Lee 2I
Sat Mar 10, 2018 12:36 am
Forum: First Order Reactions
Topic: Reaction Order [ENDORSED]
Replies: 6
Views: 366

Re: Reaction Order [ENDORSED]

I think it's more of just the exponent of the [A]. For example k[A]^2 would be a second order reaction
by Michael Lee 2I
Sat Mar 10, 2018 12:35 am
Forum: First Order Reactions
Topic: Units of Reactions. [ENDORSED]
Replies: 5
Views: 445

Re: Units of Reactions. [ENDORSED]

Basically whatever the exponent of [A] is the order of reaction.
by Michael Lee 2I
Fri Mar 02, 2018 7:50 pm
Forum: General Rate Laws
Topic: Test 3
Replies: 3
Views: 173

Re: Test 3

Ya, around number 43.
by Michael Lee 2I
Fri Mar 02, 2018 7:49 pm
Forum: Zero Order Reactions
Topic: Order Reactions [ENDORSED]
Replies: 4
Views: 371

Re: Order Reactions [ENDORSED]

The order of reactions describes how the concentrations and the rate of the reaction are correlated/related.
by Michael Lee 2I
Fri Mar 02, 2018 7:46 pm
Forum: Zero Order Reactions
Topic: Negative Order Reactions
Replies: 3
Views: 905

Re: Negative Order Reactions

Yes. I agree
by Michael Lee 2I
Thu Feb 22, 2018 9:38 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding n
Replies: 15
Views: 763

Re: Finding n

n is just the amount of electrons transferred in the reaction. Usually you need to find the half reactions first.
by Michael Lee 2I
Thu Feb 22, 2018 9:37 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs Free Energy vs. Cell Potential
Replies: 2
Views: 388

Re: Gibbs Free Energy vs. Cell Potential

This also brings up the fact that a positive E which is a negative G means the process if favorable
by Michael Lee 2I
Thu Feb 22, 2018 9:35 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E of a Redox [ENDORSED]
Replies: 5
Views: 511

Re: E of a Redox [ENDORSED]

The E value will always remain the same because it is an intensive property.
by Michael Lee 2I
Fri Feb 16, 2018 3:58 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Effect of solids and liquids on K
Replies: 3
Views: 139

Re: Effect of solids and liquids on K

Correct, only aqueous and not solids or liquids.
by Michael Lee 2I
Fri Feb 16, 2018 3:55 pm
Forum: Balancing Redox Reactions
Topic: Salt Bridges
Replies: 14
Views: 382

Re: Salt Bridges

The salt bridge keeps the two solutions neutral so that the redox reaction can continue.
by Michael Lee 2I
Fri Feb 16, 2018 3:54 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Multiplying Cathode Equation
Replies: 2
Views: 104

Re: Multiplying Cathode Equation

I agree. E is an intensive property which makes it independent of the mass.
by Michael Lee 2I
Fri Feb 09, 2018 7:33 pm
Forum: Calculating Work of Expansion
Topic: Integral [ENDORSED]
Replies: 4
Views: 201

Re: Integral [ENDORSED]

No, integrals were just done to understand the derivation.
by Michael Lee 2I
Fri Feb 09, 2018 7:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated
Replies: 9
Views: 366

Re: Isolated

The heat is changing within the isolated system. Not changing from the surroundings.
by Michael Lee 2I
Fri Feb 09, 2018 7:29 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: DG = -nFE
Replies: 3
Views: 215

Re: DG = -nFE

I think you just have to balance the equations.
by Michael Lee 2I
Fri Feb 02, 2018 7:51 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Eq.
Replies: 5
Views: 402

Re: Van't Hoff Eq.

Both delta S and delta H remain constant from what Lavelle told us in class today.
by Michael Lee 2I
Fri Feb 02, 2018 7:50 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Midterm
Replies: 6
Views: 234

Re: Midterm

Probably both chapter 8 and 9. Chapter 11 might be in there too
by Michael Lee 2I
Fri Feb 02, 2018 7:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open systems
Replies: 6
Views: 255

Re: Open systems

I think that most of the equations will deal with closed systems.
by Michael Lee 2I
Thu Jan 25, 2018 5:17 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: The sign of q
Replies: 5
Views: 213

Re: The sign of q

qsys + qsurr = 0 is a "perfect system" with no extra released/absorbed.
by Michael Lee 2I
Thu Jan 25, 2018 5:16 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes Equations
Replies: 4
Views: 209

Re: Phase Changes Equations

Most questions give the overall heat change but you should know how to solve for it. Doing a lot of problems in the textbook will give you a clearer idea on whether you need to know how to solve for the overall heat change.
by Michael Lee 2I
Thu Jan 25, 2018 5:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heat capacity vs Specific Heat capacity
Replies: 5
Views: 190

Re: Heat capacity vs Specific Heat capacity

For specific molar heat capacity you either need gas at constant volume: Cv or at constant pressure Cp.
by Michael Lee 2I
Thu Jan 18, 2018 10:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 5
Views: 208

Re: Specific Heat Capacity

It just works with the questions to assume the specific heat capacity is the same as the solvent.
by Michael Lee 2I
Thu Jan 18, 2018 10:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 5
Views: 229

Re: Hess's Law

The only thing you really need to know, since the path taken does not matter, is final state - initial state.
by Michael Lee 2I
Thu Jan 18, 2018 10:11 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Reaction Enthalpy v. Enthalpy of Formation
Replies: 4
Views: 104

Re: Reaction Enthalpy v. Enthalpy of Formation

Usually the problem states whether it involves Reaction Enthalpy or Enthalpy of Formation. Sometimes both are needed if given the information.
by Michael Lee 2I
Fri Jan 12, 2018 5:55 pm
Forum: Phase Changes & Related Calculations
Topic: Methods of Enthalpy
Replies: 8
Views: 311

Methods of Enthalpy

Are we going to have to use more than one method of finding the enthalpy in any problem?
by Michael Lee 2I
Fri Jan 12, 2018 5:53 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 4
Views: 210

Heat capacity

How is heat capacity a state function if it is an intensive property?
by Michael Lee 2I
Fri Jan 12, 2018 5:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess Law
Replies: 4
Views: 162

Hess Law

Can someone explain Hess’ law and how it pertains to the net reaction? I followed during class but was a bit confused about this.
by Michael Lee 2I
Sun Dec 03, 2017 11:00 pm
Forum: Sigma & Pi Bonds
Topic: When do Sigma and Pi bonds occur?
Replies: 4
Views: 327

Re: When do Sigma and Pi bonds occur?

Just to add on, sigma bonds also allow the molecules to rotate, whereas they are in a locked position with pi bonds.
by Michael Lee 2I
Sun Dec 03, 2017 10:58 pm
Forum: Lewis Structures
Topic: Central Atom? [ENDORSED]
Replies: 7
Views: 418

Re: Central Atom? [ENDORSED]

Hydrogen only has one electron. Because of this it cannot satisfy the octet rule and won't be the central atom
by Michael Lee 2I
Fri Nov 24, 2017 11:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Shifted VS Lie
Replies: 2
Views: 149

Re: Shifted VS Lie

I think they would rather have us say that the equilibrium sits/lies to the left or right. Using the word shift implies that there is a movement and change which is not true.
by Michael Lee 2I
Fri Nov 24, 2017 11:57 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1206

Re: Q and K [ENDORSED]

There are no difference between the formuals. However, Q refers to the reactants and products whereas K refers to the chemical equilibrium.
by Michael Lee 2I
Thu Nov 16, 2017 12:02 am
Forum: Hybridization
Topic: Notation
Replies: 6
Views: 301

Re: Notation

You only need to write it out if the question needs the full electron configuration.
by Michael Lee 2I
Thu Nov 16, 2017 12:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs Angular
Replies: 7
Views: 350

Re: Bent vs Angular

Yes, bent and angular both mean that the atoms are not bonded to the central atom linearly.
by Michael Lee 2I
Thu Nov 09, 2017 2:21 pm
Forum: Electronegativity
Topic: Ionic vs Covalent Based on Electronegativity Difference for LiI
Replies: 2
Views: 218

Re: Ionic vs Covalent Based on Electronegativity Difference for LiI

If the difference is <2 then the bond should be covalent. If the difference is >2 then the bond is ionic.
by Michael Lee 2I
Thu Nov 09, 2017 2:15 pm
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 8
Views: 428

Re: Octet Exceptions

It's true that the expanded octet applies to those with an energy level of n=3 and higher. I think the most common ones we are going to see will be Phosphorus and Sulfur.
by Michael Lee 2I
Mon Nov 06, 2017 5:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Midterm
Replies: 8
Views: 379

Re: Midterm

Nope! the exam covers material from chapters 1-3, which does not include the VSEPR model.
by Michael Lee 2I
Mon Nov 06, 2017 5:13 pm
Forum: Electronegativity
Topic: ELECTRON AFFINITY
Replies: 7
Views: 578

Re: ELECTRON AFFINITY

Are there any exceptions to the electron affinity increasing across the period?
by Michael Lee 2I
Fri Oct 27, 2017 1:10 pm
Forum: Resonance Structures
Topic: Delocalized
Replies: 2
Views: 338

Re: Delocalized

So when an electron is involved in resonance structures, it is considered delocalized.
by Michael Lee 2I
Fri Oct 27, 2017 1:08 pm
Forum: Ionic & Covalent Bonds
Topic: Cations and Anions [ENDORSED]
Replies: 12
Views: 932

Re: Cations and Anions [ENDORSED]

A cation is an atom that has lost an electron, therefore it is positive. An anion has gained an electron, making it positive. Atoms can lose or gain more than one electron.
by Michael Lee 2I
Fri Oct 20, 2017 11:33 pm
Forum: Properties of Light
Topic: Color of visible light
Replies: 11
Views: 575

Re: Color of visible light

No the most we would need to know is 400 nm being violet light and 700 nm is red light. Everything in between would either be given or it would not be asked for.
by Michael Lee 2I
Fri Oct 20, 2017 11:31 pm
Forum: Einstein Equation
Topic: Use of symbols
Replies: 6
Views: 655

Re: Use of symbols

You definitely should ask your TA because they are the ones grading, but I would say go with v because that is standard.
by Michael Lee 2I
Fri Oct 13, 2017 4:00 pm
Forum: Properties of Light
Topic: Speed of Light Constant
Replies: 18
Views: 713

Re: Speed of Light Constant

Using 2.998 x 10^8 is definitely the more accurate number. However rounding it to 3 won't cause too much of an error bound, so I don't think you would get the question wrong. But 2.998 is definitely the safe option because it is more accurate.
by Michael Lee 2I
Fri Oct 13, 2017 3:51 pm
Forum: Properties of Electrons
Topic: Series
Replies: 6
Views: 433

Re: Series

Do we still use Balmer's series if the electron is going excited from n=1 to n=2. I know that we use it when the electron goes from n=3 to n=2. Or do we use Lyman's series even though the electron ends up in the visible light spectrum?
by Michael Lee 2I
Thu Oct 05, 2017 3:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15 [ENDORSED]
Replies: 10
Views: 694

E.15 [ENDORSED]

The molar mass of the metal hydroxide M(OH)2 is 74.10 g.mol^-1. What is the molar mass of the sulfide of this metal?

I was confused on finding the molar mass of the sulfide. Is there another number I am supposed to know to use to solve this problem?
by Michael Lee 2I
Tue Oct 03, 2017 11:29 pm
Forum: Molarity, Solutions, Dilutions
Topic: G7 - Homework Problem
Replies: 5
Views: 373

Re: G7 - Homework Problem

First you find the mass of KNO3, which is the percentage (5.45%) x the total mass of the aqueous solution (510g). Then you need to find the mass of the water before the KNO3 is added to it which is the total mass of the aqueous solution (510g) subtracted by the mass of KNO3. So to prep the solution ...

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