Search found 30 matches

by joycelee1A
Fri Mar 16, 2018 12:47 pm
Forum: Experimental Details
Topic: Rate Unit Conversion
Replies: 4
Views: 361

Re: Rate Unit Conversion

I remember that on the test we took on kinetics, when asking for half time, the question specifically asked for the answer to be in seconds. So, probably, the best would be to use seconds unless the problem specifically asks for another measurement of time to be used.
by joycelee1A
Thu Mar 15, 2018 9:39 pm
Forum: *Ethers
Topic: Nucleophile
Replies: 3
Views: 581

Re: Nucleophile

A nucleophile is a chemical species attracted to positive charges. Therefore, they would be negatively charged.
by joycelee1A
Thu Mar 15, 2018 9:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: The Effect of Temperature
Replies: 3
Views: 114

Re: The Effect of Temperature

Raising the temperature raises the rate constant as well.
by joycelee1A
Thu Mar 15, 2018 9:36 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs and Activation Energy
Replies: 4
Views: 285

Re: Gibbs and Activation Energy

From my discussion section, on the reaction profile, our TA defined the difference in energy between the reactants and products as the ∆G (in reference to kinetics). Activation energy is the minimum energy required for the reaction to take place. I don't think we defined much of a relationship betwe...
by joycelee1A
Mon Mar 05, 2018 4:58 pm
Forum: Second Order Reactions
Topic: Limiting Step
Replies: 7
Views: 435

Re: Limiting Step

Akash_Kapoor_1L wrote:Do we have to know how to calculate the limiting step for test 3? Which hw problems focus on the limiting step?


I don't think so. Dr. Lavelle said test three would go up to 15.6, and this topic isn't on there.
by joycelee1A
Mon Mar 05, 2018 4:33 pm
Forum: Experimental Details
Topic: Rate Constant
Replies: 4
Views: 304

Re: Rate Constant

Any of the experiments should work for finding the rate constant.
by joycelee1A
Mon Mar 05, 2018 4:30 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Laws of Elementary Reactions
Replies: 4
Views: 124

Re: Rate Laws of Elementary Reactions

No, I don't think you would be able to do that for an overall reaction. The example you gave was for a bimolecular elementary step in which then I think your assumption may be correct.
by joycelee1A
Mon Mar 05, 2018 4:18 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Molecularity
Replies: 3
Views: 97

Re: Molecularity

The textbook defines molecularity as the number of reactant molecules or species taking part in a specified elementary reaction, so I would think that it has to do with the elementary step and not the overall reaction.
by joycelee1A
Mon Mar 05, 2018 4:16 pm
Forum: Zero Order Reactions
Topic: Pseudo Zero Order Reactions
Replies: 3
Views: 405

Re: Pseudo Zero Order Reactions

I don't think so since zero order reactions don't have to do with the concentration of the reactants.
by joycelee1A
Thu Mar 01, 2018 7:29 pm
Forum: Zero Order Reactions
Topic: Catalysts
Replies: 2
Views: 129

Re: Catalysts

A zero order reaction is when the rate is independent of the reactant concentration. From what I remember, they occur most often when the reaction is catalyzed. So, zero order reactions usually/most often happen with a catalyst involved. For example, if a substrate attaches to the activation site of...
by joycelee1A
Thu Mar 01, 2018 7:22 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Law [ENDORSED]
Replies: 2
Views: 101

Re: Rate Law [ENDORSED]

I believe that the rate law is in reference to the reactants. For the coefficients, I think it has to do with the way the rate is defined. Like coefficients matter in the equation where rate=(1/a)d[A]/d[t]. Besides this equation, I'm not too sure about the coefficients.
by joycelee1A
Fri Feb 23, 2018 12:59 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Reducing Agent/ Oxidizing Agent
Replies: 6
Views: 365

Re: Reducing Agent/ Oxidizing Agent

From what I remember from during my discussion section, the more positive potential means its a greater oxidizing agent and after the potential, the size would be the next determining factor.
by joycelee1A
Fri Feb 23, 2018 12:50 pm
Forum: First Order Reactions
Topic: Reaction order
Replies: 4
Views: 171

Re: Reaction order

The method we learned today in class was the method of using initial rates. You set up a ratio of concentrations and rates of two of the experiments to the equation rate=k[A]^n and then solve for n which makes the ratio true.
by joycelee1A
Fri Feb 23, 2018 12:24 pm
Forum: General Rate Laws
Topic: Doubling Concentration in Second-Order Reaction
Replies: 2
Views: 101

Re: Doubling Concentration in Second-Order Reaction

It means that doubling the concentration for a second order reaction should increase the reaction rate by four times the original reaction rate. So mathematically, since the concentration is being raised to the second power, doubling it would cause it to be 2^2 or times 4.
by joycelee1A
Fri Feb 23, 2018 12:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram [ENDORSED]
Replies: 4
Views: 148

Re: Cell diagram [ENDORSED]

You use single lines between different states and a comma for multiple species in the same state.
by joycelee1A
Sun Feb 11, 2018 3:36 pm
Forum: Van't Hoff Equation
Topic: Free Energy, pressure, and equilibrium constant
Replies: 2
Views: 210

Re: Free Energy, pressure, and equilibrium constant

I don't have a direct conceptual answer, but there were two equations given which both have pressure and the equilibrium constant which solves for Free energy. ∆G=nRTln(P2/P1) (for pressure) and ∆Go=-RTlnK.
by joycelee1A
Fri Feb 09, 2018 6:02 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Concept
Replies: 1
Views: 91

Re: Entropy Concept

If you think about a spontaneous natural process of heat flowing from a hot region to a cold region, the entropy for the hot region would be S1=q/T. The entropy for the cold region would be S2=q/T. So if you calculate ∆S=S2-S1, ∆S is positive since T2<T1. There was an increase in the entropy of the ...
by joycelee1A
Fri Feb 09, 2018 5:54 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: Degeneracy
Replies: 2
Views: 114

Re: Degeneracy

Degeneracy is the number of ways a given energy state can be achieved. I think one way is you can raise the number of states possible to the number of atoms. So if there were 2 states possible and 3 atoms, it would be 2^3.
by joycelee1A
Fri Feb 02, 2018 3:49 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: When to use Q versus K [ENDORSED]
Replies: 6
Views: 473

Re: When to use Q versus K [ENDORSED]

I think you use Q when the system is not in equilibrium.
by joycelee1A
Fri Feb 02, 2018 3:07 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Work and Reversible Process [ENDORSED]
Replies: 2
Views: 108

Work and Reversible Process [ENDORSED]

Can someone explain more concisely why a process produces maximum work in a reversible reaction? I don't fully understand why.
by joycelee1A
Fri Feb 02, 2018 3:05 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Clausius Inequality [ENDORSED]
Replies: 1
Views: 76

Clausius Inequality [ENDORSED]

The textbook mentions a Clausius Inequality, ∆S≥q/t. Could someone explain the importance for it and what it is saying about the reaction? (Also do we need to know about it for the class?)
by joycelee1A
Fri Jan 26, 2018 1:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State properties of heat and enthalpy
Replies: 2
Views: 137

Re: State properties of heat and enthalpy

Heat is not an intrinsic property and depends on the path of the reaction. Tt occurs when there is a change in the system. Heat provides information on how the final state was attained not just the final and initial state. The energy transferred through heat does depend on how it is transferred, and...
by joycelee1A
Fri Jan 26, 2018 1:00 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacities of monatomic gas and linear molecule
Replies: 2
Views: 123

Heat Capacities of monatomic gas and linear molecule

I don't fully understand the two equations of 3/2R and 5/2R, or why they are the equations for the heat capacities of a monatomic gas and linear molecule. Do we have to necessarily know this information?
by joycelee1A
Fri Jan 26, 2018 12:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible Vs Irreversible
Replies: 3
Views: 108

Reversible Vs Irreversible

Why is the temperature constant in reversible reactions whereas temperature changes along the path for irreversible reactions?
by joycelee1A
Fri Jan 19, 2018 4:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: P delta V is significant?
Replies: 2
Views: 168

Re: P delta V is significant?

I'm not sure about all the details of it, but I do know that with solids and liquids, the volume can't really change and there's no expansion work being done. Since the pressure is constant, and liquids and solids aren't compressible, the volume isn't changing either.
by joycelee1A
Fri Jan 19, 2018 4:05 pm
Forum: Phase Changes & Related Calculations
Topic: 8.39
Replies: 2
Views: 115

8.39

I didn't fully understand 8.39. The question asks for the amount of heat needed to convert 80.0g of ice at 0 °C into liquid water at 20°C. Would there be a calculation for phase change we need to take into consideration? I wasn't sure how to go about it.
by joycelee1A
Thu Jan 18, 2018 4:05 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic [ENDORSED]
Replies: 8
Views: 343

Re: Adiabatic [ENDORSED]

My TA mentioned it too. I'm not entirely sure, but my TA mentioned that it would be a closed system with no heat transfer.
by joycelee1A
Sat Jan 13, 2018 12:59 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeter
Replies: 2
Views: 106

Bomb Calorimeter

Can someone explain how bomb calorimeter works, and would we need to know technically how it works?
by joycelee1A
Thu Jan 11, 2018 4:56 pm
Forum: Phase Changes & Related Calculations
Topic: Temperature during phase changes [ENDORSED]
Replies: 4
Views: 254

Re: Temperature during phase changes [ENDORSED]

The energy used to otherwise increase the temperature (specific heat) is instead used to change phases (heat of fusion). Once the temperature for the boiling point or melting point is reached, the energy that would have raised the temperature goes into changing the phase.
by joycelee1A
Thu Jan 11, 2018 4:30 pm
Forum: Phase Changes & Related Calculations
Topic: ∆Hsub= ∆Hfus+ ∆Hvap
Replies: 4
Views: 356

Re: ∆Hsub= ∆Hfus+ ∆Hvap

If you think of it from a mathematical standpoint, you can substitute ∆Hfus and ∆Hvap with their equations to get the original ∆Hsub equation. ∆Hfus=Hliquid-Hsolid and ∆Hvap=Hvapor-Hliquid. So if you substitute it, ∆Hsub= (Hliquid-Hsolid) + (Hvapor-Hliquid). The Hliquid cancels out leaving Hvapor-Hs...

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