CHEMISTRY COMMUNITY

JeremyPark14B

Under what conditions is delta U = 0?

JeremyPark14B

What is the purpose behind integrating rate laws? What do the integrated rate law equations do?

JeremyPark14B

If the problem gives a reaction mechanism, but doesn't state which is slow / fast, how can we determine the determining step rate law or overall rate reaction rate law?

JeremyPark14B

In the constants and equations sheet, I noticed that there are 2 equations for Nernst's Equation:

E = Enot - (RT/nF) x lnQ .

E = Enot - (0.05916/n) logQ

What is the difference between the two?

JeremyPark14B

Would the Ecell naught of a concentration cell be 0? Because the E naughts of the cathode and anode would just be the opposite of each other and thus cancel out?

JeremyPark14B

When given 2 different concentrations, how do we know which concentration belongs to the oxidation / reduction reactions? In other words, how do we determine which concentration belongs to the anode and the cathode? The problem I am looking at states that the electrons are flowing from the left elec...

JeremyPark14B

I know this isn't exactly equilibrium, but I wasn't sure where to ask it. For the final, in what context are we going to need to know and apply the Ka x Kb = Kw?

JeremyPark14B

When finding the activation energy with the arrhenius equation in a temperature change, we use ln(k1/k2) = Ea/R (1/T2 - 1/T1).

Will k2 and k1 both always be given? If only one is given, how do we find the other?

JeremyPark14B

How do changes in concentrations of reactants and products affect the cell potential?

JeremyPark14B

What is the difference between electrochemical series and reduction potentials?

JeremyPark14B

Are we going to be required to know how to derive the integrated rate laws? Doesn't that require a background in calculus?

JeremyPark14B

When are we required to write Pt(s) on the outsides of the cell diagram? What exactly is Pt(s)?

JeremyPark14B

Why do we have to do use delta G = -nFE? Why can't we just add the E values of the 2 half reactions that make up the U4+ +4e- -> U(s)

JeremyPark14B

In part a, the half reaction within the main reaction is 6Hg -> 3Hg2 2+ + 6e-

In the reduction potential E values, Hg2 2+ + 2e- -> 2Hg E = +.79.

Why are we to use the +.79 instead of flipping the sign to -.79 since the oxidation version of this reaction is done in the actual reaction?

JeremyPark14B

So Cv = (3/2)R is used when volume is constant

and Cp = (5/2)R is used when pressure is constant.

In the practice midterm worksheets, when volume is being changed, the answer key says to use Cv. Why is this so?

JeremyPark14B

How does the 2nd law of thermodynamics relate to the equation of delta S = q(rev) / T ?

The 2nd law states that spontaneous processes lead to an increase in entropy. However, if q is negative, isn't the change in entropy negative? How does this make sense?

JeremyPark14B

In the Learning Outcomes for thermodynamics, it lists that we should know how to calculate change in energy and entropy from the 1st and 2nd laws of thermodynamics. How do we calculate entropy with the first and second laws?

JeremyPark14B

I believe boltzmann equation will be used when dealing with microstates. The other equation is used when calculating change in entropy within a volume change in the system: delta S = n R ln(v2 / v1)

JeremyPark14B

What is the explanation behind Boltzmann's Equation? What exactly does it solve for?

JeremyPark14B

How will we be required to relate thermochemistry / thermodynamics to organic and biological examples?

JeremyPark14B

What is the difference between delta U and delta H?

Delta U is the change in internal energy of a system... and delta H is the change in heat energy. What is the difference between the two in respect to a system?

JeremyPark14B

I saw this on the learning outcomes for thermochem; how does enthalpy being a state function justify Hess's Law?

JeremyPark14B

Will we be required to know / explain the integral justification for w = P delta V?

JeremyPark14B

In the textbook, the equation for delta S with given temperature change is Delta S = C x ln(T2/T1)

However, in the answer book, the equation Delta S = n x C x ln(T2/T1) is used.

Why is n neglected? Thank you for your time.

JeremyPark14B

Why is it that when calculating for the enthalpy of a phase change, it is (moles)(standard enthalpy of phase change) but when calculating a change in temperature, it becomes (grams)(specific heat)? For example, how much heat is needed to convert 80.0 g of ice at 0.0 C into liquid water at 20.0 C: th...

JeremyPark14B

Christopher Tran 1J wrote:Cp refers to the heat required to raise the temperature of one mole gas by 1 degree C at constant pressure, and Csp refers to the heat required to raise the temperature of one gram gas by 1 degree C at constant pressure.

How will we know when to use Cp or Csp? Will it be give in the question?

JeremyPark14B

delta H is the change in heat; the measure of heat; isn't q also a measure of heat? what is the difference between delta H and q?

JeremyPark14B

Are we required the write the questions from the textbook down? Or is only showing work OK?

JeremyPark14B

if X is smaller than 10^-3, adding it into a number will have nearly no effect. However, X^2 is significantly larger than just X. Therefore if X is smaller than 10^-3, it is negligible.

CHEMISTRY COMMUNITY

Search found 29 matches

When is delta U = 0?

Integrated Rate Law graphs

Reaction Mechanisms without unknown rate-determining step

Nernst Equation

Concentration cells Ecell

Concentration Cells

Ka Kb = Kw

Arrhenius Equation question

Effect of concentration on cell potential

What is the difference between electrochemical series and reduction potentials?

Deriving integrated rate laws

When to put Pt(s) in a cell diagram?

14.27, 6th Edition

6h Edition; 14.23

Cv vs. Cp

2nd law of Thermodynamics

Calculating change in entropy from 1st and 2nd laws of Thermodynamics

Re: Entropy Equations

Explaining Boltzmann's Equation

Applying to biological and organic examples

Difference between delta U and delta H?

Explaining Hess's Law with enthalpy = a state function?

Proving the work equation

Difference between 2 delta S equations?

Phase change equations

Re: Cp vs. Csp

What is the difference between delta H and q?

Chem 14b weekly homework

Re: ICE Table