Search found 30 matches

by Tameen Ahmed 4C
Sat Mar 16, 2019 1:34 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isometric/Isochoric
Replies: 10
Views: 296

Re: Isometric/Isochoric

Yes, a bomb calorimeter is a type of constant-volume calorimeter so it can be considered isometric.
by Tameen Ahmed 4C
Sat Mar 16, 2019 1:31 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Equation
Replies: 8
Views: 298

Re: Equation

I think we should assume A is 1 unless otherwise stated
by Tameen Ahmed 4C
Sat Mar 16, 2019 1:29 am
Forum: *Enzyme Kinetics
Topic: How do you tell if something is a catalyst vs an intermediate?
Replies: 13
Views: 530

Re: How do you tell if something is a catalyst vs an intermediate?

A catalyst is consumed by a step but regenerated by a later step. An intermediate is created by a step but consumed by a later step.
by Tameen Ahmed 4C
Sat Mar 16, 2019 1:27 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: H+ in Cell Diagram
Replies: 3
Views: 58

Re: H+ in Cell Diagram

You should always include H+ in your cell diagram if it's present in your half reactions.
by Tameen Ahmed 4C
Sat Mar 16, 2019 1:17 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Ecell
Replies: 4
Views: 75

Re: Ecell

You can find the Ecell by using two methods:
1) Ecell= ECathode-Eanode
2) Ecell=Eanode+Ecathode <-- for this method, you need to change the sign of the anode value from the reduction table
by Tameen Ahmed 4C
Sat Mar 16, 2019 1:04 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Stability and Enthalpy
Replies: 1
Views: 198

Re: Stability and Enthalpy

Feel free to correct me if I'm wrong, but I think a higher enthalpy indicates less stability whereas a lower enthalpy indicates more stability.
by Tameen Ahmed 4C
Sat Mar 16, 2019 12:58 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Cp vs Cv
Replies: 6
Views: 458

Re: Cp vs Cv

It'll be specified in the question! If they say the gas is in constant pressure or constant volume then you would use them
by Tameen Ahmed 4C
Thu Mar 14, 2019 3:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Assuming ideal gas
Replies: 3
Views: 215

Re: Assuming ideal gas

I think you assume the question is referring to an ideal gas unless otherwise stated!
by Tameen Ahmed 4C
Thu Mar 14, 2019 3:21 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: intermediates vs. catalysts
Replies: 2
Views: 47

Re: intermediates vs. catalysts

Yes! A catalyst is consumed by a step but regenerated by a later step while an intermediate is created by a step but consumed by a later step.
by Tameen Ahmed 4C
Thu Mar 14, 2019 3:17 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Intermediate vs catalyst
Replies: 8
Views: 106

Re: Intermediate vs catalyst

A catalyst is consumed by a step but regenerated by a later step. An intermediate is created by a step but consumed by a later step.
by Tameen Ahmed 4C
Wed Mar 13, 2019 8:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Questions
Replies: 10
Views: 358

Re: Final Questions

Jonathan Christie 1I wrote:Where can you look at past finals?


Do they have past finals at the test bank at the Student Activities Center?
by Tameen Ahmed 4C
Wed Mar 13, 2019 8:46 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics Plots
Replies: 5
Views: 211

Re: Kinetics Plots

If it's a straight line with a negative slope then it can be zero order or first order. If the graph displays [A] vs. time with a negative slope then it's zero order and if the graph displays ln[A] vs time with a negative slope then it's a first order reaction. A second order reaction would be plott...
by Tameen Ahmed 4C
Wed Mar 13, 2019 8:40 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: example
Replies: 2
Views: 52

Re: example

I think a catalyst is consumed by a step in the beginning but then appears again later by another step while an intermediate is created by one step and consumed later on in another step. (Correct me if I'm wrong)
by Tameen Ahmed 4C
Wed Mar 13, 2019 8:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 8
Views: 141

Re: Anode and Cathode

If it gets oxidized then it is an anode and if it gets reduced then it is a cathode. I like to think "an ox" and "red cat" when working with half reactions and find it easier to draw my cell diagrams with anode to the left and cathode to the right since it's presented like that i...
by Tameen Ahmed 4C
Wed Mar 13, 2019 8:31 pm
Forum: Phase Changes & Related Calculations
Topic: Isothermic vs. Adiabatic
Replies: 3
Views: 182

Re: Isothermic vs. Adiabatic

In an adiabatic system, there is no heat transferred; therefore, the total change in internal energy of the system is equal to the work performed (deltaU=w). In an isothermal system, there's no change in temperature; therefore, the total internal energy of the system doesn't change (deltaU=0). Becau...
by Tameen Ahmed 4C
Tue Mar 05, 2019 4:44 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs free energy and temperature
Replies: 3
Views: 100

Re: Gibbs free energy and temperature

Temperature is a factor of TΔS, so a high temperature will favor spontaneity if ΔS is positive and will not favor spontaneity if ΔS is negative.
by Tameen Ahmed 4C
Tue Mar 05, 2019 4:20 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Changing concentration to change rate
Replies: 2
Views: 57

Re: Changing concentration to change rate

Typically, reaction rates decrease with time because reactant concentrations decrease as reactants are converted to products. Reaction rates generally increase when reactant concentrations are increased.
by Tameen Ahmed 4C
Tue Mar 05, 2019 4:10 pm
Forum: General Rate Laws
Topic: General Rate Law Orders
Replies: 3
Views: 52

Re: General Rate Law Orders

First order, would be natural log of concentration A versus time. If you get a straight line with a negative slope, then that would be first order. For second order, if you graph the inverse of the concentration A versus time, you get a positive straight line with a positive slope, then you know it'...
by Tameen Ahmed 4C
Fri Mar 01, 2019 8:51 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic and Endothermic Reactions
Replies: 4
Views: 236

Re: Exothermic and Endothermic Reactions

You can use Le Chatelier's principle to understand this concept. If you increase the temperature you are increasing the amount of products, and so you shift the balance at equilibrium back toward reactants, meaning there will be more reactants left at equilibrium. The higher the temperature goes, th...
by Tameen Ahmed 4C
Fri Mar 01, 2019 8:45 pm
Forum: Balancing Redox Reactions
Topic: Short hand notation
Replies: 8
Views: 150

Re: Short hand notation

Expanding on the previous comment, a salt bridge, in electrochemistry, is used to connect the oxidation and reduction half-cells of a galvanic cell. It maintains electrical neutrality within the internal circuit, which in turn prevents the call from going into equilibrium.
by Tameen Ahmed 4C
Fri Mar 01, 2019 8:40 pm
Forum: Balancing Redox Reactions
Topic: Max Potential
Replies: 3
Views: 73

Re: Max Potential

The equation deltaG=-nFE shows us that the free energy between the reactants and products (deltaG)
is directly related to the maximum cell potential (E).
by Tameen Ahmed 4C
Thu Feb 21, 2019 4:02 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Meaning
Replies: 6
Views: 135

Re: Gibbs Free Energy Meaning

Gibbs free energy is the energy available to do work that can be shifted or morphed. A negative Gibbs free energy results in a spontaneous reaction, meaning the reactants, or initial state, have more free energy than the products, or final state.
by Tameen Ahmed 4C
Thu Feb 21, 2019 3:58 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Negative ∆G means spontaneous reaction?
Replies: 5
Views: 117

Re: Negative ∆G means spontaneous reaction?

Negative ∆G corresponds to a spontaneous reaction because reactants, or initial state, have more free energy than the products, or final state.
by Tameen Ahmed 4C
Thu Feb 21, 2019 3:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Units of Delta G
Replies: 5
Views: 103

Re: Units of Delta G

The units for delta G are either KJ or J
by Tameen Ahmed 4C
Thu Feb 14, 2019 8:33 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Temperature and Equilibrium
Replies: 3
Views: 82

Re: Temperature and Equilibrium

It depends on the delta H of the reaction. If the reaction is endothermic and the temperature is increased, the reaction will shift to the right. If the reaction is exothermic and the temperature is increased, the reaction will shift to the left.
by Tameen Ahmed 4C
Thu Feb 14, 2019 3:48 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible vs. Irreversible
Replies: 5
Views: 319

Re: Reversible vs. Irreversible

For a reversible reaction, delta S of the system is equal to -delta S of the surrounding because delta S universe is equal to zero. For this reaction, you would use w=-nRTln(V2/V1). For an irreversible reaction, delta S of the universe is equal to delta S of the system because delta S of the surroun...
by Tameen Ahmed 4C
Thu Feb 14, 2019 3:41 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Cp,m
Replies: 5
Views: 248

Re: Cp,m

Cp,m and Cv,m are used for isothermal reactions with ideal gases. Cp,m is used when an constant temperature is given and Cv,m is used when a constant volume is given.
by Tameen Ahmed 4C
Thu Feb 07, 2019 3:55 pm
Forum: Phase Changes & Related Calculations
Topic: sections
Replies: 4
Views: 96

Re: sections

According to the class website, we're going to be tested on, Chemical Equilibrium, Acid and Base Equilibria, Thermochemistry, and Thermodynamics to the end of entropy.
by Tameen Ahmed 4C
Thu Feb 07, 2019 3:48 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs. Irreversible
Replies: 2
Views: 47

Re: Reversible vs. Irreversible

You have to be given certain information about a reaction to formulate and calculate things about a reaction, and one information is whether or not a reaction is reversible or not. Forgive me if I’m wrong, but I think a problem will typically tell you whether or not a reaction is reversible or irrev...
by Tameen Ahmed 4C
Thu Feb 07, 2019 3:39 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy units
Replies: 3
Views: 46

Re: Entropy units

The units for entropy are J/K and I believe there aren't any units for degeneracy but I'm not quite certain!

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