Search found 30 matches

by PranitKumaran1F
Fri Mar 15, 2019 11:55 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Exothermic vs Endothermic
Replies: 6
Views: 74

Re: Exothermic vs Endothermic

If the Ea of the forward rxn is greater than the Ea of the reverse rxn, then it is endothermic and vise versa
by PranitKumaran1F
Fri Mar 15, 2019 11:46 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Work
Replies: 4
Views: 141

Cell Work

How can I determine the maximum work done by a cell in standard state conditions?
by PranitKumaran1F
Fri Mar 15, 2019 11:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady State Equilibirum
Replies: 2
Views: 34

Re: Steady State Equilibirum

No we only need to know the pre-equilibrium approach
by PranitKumaran1F
Tue Mar 12, 2019 4:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Test 2: Why is photosynthesis spontaneous?
Replies: 2
Views: 150

Re: Test 2: Why is photosynthesis spontaneous?

For that question, my TA said that you should assume that the free energy from the sun is included in the reaction for photosynthesis, so the net free energy after the reaction completes is less than zero.
by PranitKumaran1F
Tue Mar 12, 2019 4:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 2 #5
Replies: 1
Views: 36

Re: Test 2 #5

You do the second way. You can't assume that [H30]=[OH] in a pH = 7 solution because that only applies when K = 10^-14. Since K2 will be a different value, you have to solve for [OH] by dividing K2 by [H30] in a pH=7 solution. If [H30]>[OH] then the solution is acidic at pH = 7 and vise versa.
by PranitKumaran1F
Tue Mar 12, 2019 4:29 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Electrode
Replies: 2
Views: 39

Re: Inert Electrode

Yes, either side of the cell that doesn't have a solid-state conducting metal in the reaction, then you need an inert electrode on that side.
by PranitKumaran1F
Tue Mar 12, 2019 10:34 am
Forum: General Rate Laws
Topic: Derivations
Replies: 3
Views: 48

Re: Derivations

The rate formulas are given on the constants and equations sheet, but you have to know yourself which equation corresponds with which reaction order.
by PranitKumaran1F
Tue Mar 12, 2019 10:18 am
Forum: First Order Reactions
Topic: Doubling the Concentration
Replies: 4
Views: 51

Re: Doubling the Concentration

The reaction order is dependent on the exponent of the reactant concentration, not the value of the concentration itself. With that, doubling the reactant concentration would only double the rate, since the rate law for a first order reaction is rate=k[A]. The reaction order and reactant concentrati...
by PranitKumaran1F
Tue Mar 12, 2019 10:15 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: slow step and fast step
Replies: 3
Views: 46

Re: slow step and fast step

The slow step actually does determine the overall rate, since the reaction is only as fast as its slowest step
by PranitKumaran1F
Tue Mar 12, 2019 10:13 am
Forum: General Rate Laws
Topic: Zero Order Reactions
Replies: 4
Views: 77

Re: Zero Order Reactions

In the rate law for zero order reactions, the exponent of the reactant concentrations are zero, meaning the rate will simply equal to k, so reactant concentration will not matter.
by PranitKumaran1F
Thu Feb 21, 2019 11:28 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox Rxns
Replies: 2
Views: 46

Re: Balancing Redox Rxns

Pay attention to the charges of each species in the reaction and which ones are being oxidized and reduced. Make the coefficients of the species so that the moles of electrons transferred are equal.
by PranitKumaran1F
Thu Feb 21, 2019 11:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: nerst equation
Replies: 3
Views: 34

Re: nerst equation

standard cell potential is for reactions that are in equilibrium while cell potential is calculated from the Nernst equation for reactions that may or may not be in equilibrium
by PranitKumaran1F
Thu Feb 21, 2019 11:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: nerst equation
Replies: 3
Views: 34

Re: nerst equation

You can use it to mainly predict a cell potential of an electrochemical reaction or finding the concentrations of the species of an electrochemical reaction.
by PranitKumaran1F
Thu Feb 21, 2019 11:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 4
Views: 58

Anode and Cathode

How do you identify the anode and cathode in a galvanic cell?
by PranitKumaran1F
Thu Feb 21, 2019 3:57 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Units of Delta G
Replies: 5
Views: 76

Re: Units of Delta G

Delta G is the measure of the change in free energy in a reaction, so you would use either J or KJ; However, you use KJ/mol or J/mol as the units when in respect to a certain number of moles of the species in the reaction.
by PranitKumaran1F
Thu Feb 21, 2019 3:46 pm
Forum: Balancing Redox Reactions
Topic: sections covered on test
Replies: 4
Views: 84

Re: sections covered on test

Professor Lavelle announced on his website that the test will cover Gibbs Free Energy and everything learned from electrochemistry up to but not including the Nernst equation (new material from Weeks 6 and 7).
by PranitKumaran1F
Thu Feb 21, 2019 3:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.53 Homework Problem
Replies: 1
Views: 24

Re: 9.53 Homework Problem

You would have to find the standard reaction entropy and enthalpy of the reaction using the values from the tables given for each compound in the reaction. Then you would use the different T values along with the calculated deltaS and deltaH values to find the Gibbs free energy if the reaction using...
by PranitKumaran1F
Thu Feb 21, 2019 3:25 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 4J.7) 7th edition of the textbook
Replies: 2
Views: 38

Re: 4J.7) 7th edition of the textbook

The enthalpy of formation of any element in its stable form, which in this case is F2 and O2, is always zero, so there isn't a need to take their enthalpies of formations into account.
by PranitKumaran1F
Thu Feb 21, 2019 3:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: equation explanation
Replies: 2
Views: 35

Re: equation explanation

deltaG^0 refers to the Gibbs free energy of a reaction in equilibrium, but RTlnQ is used to find the Gibbs free energy of a reaction that is not in equilibrium, which can be shown through the fact that the Q of a reaction is the ratio of products to reactants for reactions that may or may not be in ...
by PranitKumaran1F
Thu Feb 21, 2019 3:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating Gibbs
Replies: 2
Views: 51

Re: Calculating Gibbs

n is the number of moles of electrons transferred in an electrochemical reaction; for example, in a reaction such as Cu^2+ + 2e- --> Cu, n=2 since two moles of electrons are transferred in this reaction.
by PranitKumaran1F
Thu Feb 21, 2019 2:58 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Units for Gibbs
Replies: 8
Views: 117

Re: Units for Gibbs

As long as they are the same units it doesn't matter, whatever is easier for you.
by PranitKumaran1F
Thu Feb 21, 2019 2:12 pm
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 10
Views: 121

Re: Oxidation States

Oxidation states of elements such as transition metals can be calculated based on the reaction they are in, so they don't need to be memorized.
by PranitKumaran1F
Mon Feb 11, 2019 4:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of Phase Changes
Replies: 4
Views: 64

Re: Enthalpy of Phase Changes

more energy is required to separate the molecules of a liquid into a gas than it is for a solid to liquid
by PranitKumaran1F
Mon Feb 11, 2019 3:59 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpies
Replies: 10
Views: 141

Re: Bond enthalpies

Knowing the Lewis structure would make it easier because then you would only need the calculate the specific bonds that are broken and formed, but if you don't know the Lewis structure you can still calculate bond enthalpies by calculating with all the bonds being formed and broken as well.
by PranitKumaran1F
Mon Feb 11, 2019 3:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 56

Re: bond enthalpies

bond enthalpies can be used for solids and liquids as well
by PranitKumaran1F
Mon Feb 11, 2019 3:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Using R
Replies: 10
Views: 162

Re: Using R

R=8.314 J mol-1 K-1 is used more for solving for an energy value while R = .08206 L atm mol-1 K-1 is for when solving for either pressure or volume of a gas.
by PranitKumaran1F
Mon Feb 11, 2019 3:33 pm
Forum: Ideal Gases
Topic: The Difference between Q and Kc
Replies: 12
Views: 397

Re: The Difference between Q and Kc

K is the ratio of the products and reactants when the reaction is at equilibrium only, while Q is the ratio of the products and the reactants at any given point in the reaction.
by PranitKumaran1F
Mon Feb 11, 2019 3:30 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Signs for entropy
Replies: 5
Views: 94

Re: Signs for entropy

If the reaction is endothermic, you know that delta H is positive because the reaction absorbs heat. If the reaction is exothermic, then delta H would be negative because the reaction gives off heat.
by PranitKumaran1F
Sun Jan 13, 2019 2:47 pm
Forum: Ideal Gases
Topic: Units
Replies: 19
Views: 225

Re: Units

The units should be in kelvin using the ideal gas law equation
by PranitKumaran1F
Sun Jan 13, 2019 2:44 pm
Forum: Administrative Questions and Class Announcements
Topic: HW 2 Due Date
Replies: 4
Views: 76

Re: HW 2 Due Date

Week 1 hw was due on Friday but all homework afterward will be due in your discussion sections.

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