CHEMISTRY COMMUNITY

PranitKumaran1F

If the Ea of the forward rxn is greater than the Ea of the reverse rxn, then it is endothermic and vise versa

PranitKumaran1F

How can I determine the maximum work done by a cell in standard state conditions?

PranitKumaran1F

No we only need to know the pre-equilibrium approach

PranitKumaran1F

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.

PranitKumaran1F

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.

PranitKumaran1F

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.

PranitKumaran1F

The rate formulas are given on the constants and equations sheet, but you have to know yourself which equation corresponds with which reaction order.

PranitKumaran1F

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...

PranitKumaran1F

The slow step actually does determine the overall rate, since the reaction is only as fast as its slowest step

PranitKumaran1F

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.

PranitKumaran1F

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.

PranitKumaran1F

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

PranitKumaran1F

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.

PranitKumaran1F

How do you identify the anode and cathode in a galvanic cell?

PranitKumaran1F

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.

PranitKumaran1F

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).

PranitKumaran1F

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...

PranitKumaran1F

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.

PranitKumaran1F

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 ...

PranitKumaran1F

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.

PranitKumaran1F

As long as they are the same units it doesn't matter, whatever is easier for you.

PranitKumaran1F

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.

PranitKumaran1F

more energy is required to separate the molecules of a liquid into a gas than it is for a solid to liquid

PranitKumaran1F

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.

PranitKumaran1F

bond enthalpies can be used for solids and liquids as well

PranitKumaran1F

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.

PranitKumaran1F

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.

PranitKumaran1F

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.

PranitKumaran1F

The units should be in kelvin using the ideal gas law equation

PranitKumaran1F

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

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Exothermic vs Endothermic

Cell Work

Re: Steady State Equilibirum

Re: Test 2: Why is photosynthesis spontaneous?

Re: Test 2 #5

Re: Inert Electrode

Re: Derivations

Re: Doubling the Concentration

Re: slow step and fast step

Re: Zero Order Reactions

Re: Balancing Redox Rxns

Re: nerst equation

Re: nerst equation

Anode and Cathode

Re: Units of Delta G

Re: sections covered on test

Re: 9.53 Homework Problem

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

Re: equation explanation

Re: Calculating Gibbs

Re: Units for Gibbs

Re: Oxidation States

Re: Enthalpy of Phase Changes

Re: Bond enthalpies

Re: bond enthalpies

Re: Using R

Re: The Difference between Q and Kc [ENDORSED]

Re: Signs for entropy

Re: Units

Re: HW 2 Due Date