CHEMISTRY COMMUNITY

Melody P 2B

Concentration cells contain the same components but at differing concentrations. So, the anode and cathode are the same in terms of what they are, but not their concentrations. For example, in class Lavelle used 0.1 M of Ag⁺ and 1 M of Ag⁺

Melody P 2B

In lector today (3/11) Dr. Llavelle briefly spoke about what determines the magnitude of K, can someone clarify what he meant by this? It was toward the end of the lecture so I wasn't able to write everything down. Thank you. Are you referring to capital K(equilibrium)? or lowercase k (rate constan...

Melody P 2B

Yes, because the half life equations are derived from the integrated rate laws. And the integrated rate laws differ in terms of reaction order.

This should help!

Melody P 2B

When the concentration of a reactant is independent of the rate does that mean it's zero order? And how would we be able to tell given a table of initial rates/concentrations?

Melody P 2B

This kind of helps answer your question.

Differential-and-Integrated-Rate-Laws1.pdf: (508.57 KiB) Downloaded 3461 times

Melody P 2B

I think the difference is just that the Differential Rate Law uses derivatives, but we want to make the analysis easier/"better" so to get rid of the derivatives we integrate. So, the Differential Rate Law expresses the rate of the reaction as a function of change in concentration over tim...

Melody P 2B

Chase Yonamine 1J wrote:The smallest (more negative) Reduction potential is a stronger reducing agent

Why is that?

Melody P 2B

Most likely not, since the first test wasn't. I would not expect test 2 to be curved. :(

Melody P 2B

Would you add Pt(s) to both sides?

Melody P 2B

E cell refers to electrode potential of a cell.

E^o cell refers to standard electrode potential where electrode potential is measured at 1 atmosphere pressure, 1 molar solution at 25° C.(aka standard conditions)

Melody P 2B

Lavelle mentioned in lecture on Friday that Test 2 would cover Gibbs Free Energy up until what the lecture covered Friday.

Melody P 2B

H⁺ + Cr₂O₇^2-+C₂H₅OH ----> Cr³⁺ + H₂O

The oxidized reaction is C₂H₅OH ---> C₂H₄O

The solutions manual says C is oxidized from 2- to 1- but when I do the math I get from 2- to 1+ , what am I doing wrong?

Melody P 2B

This may be of some help!!! It can also be found on the course website

Balancing_Redox_Reactions_Acidic_Conditions.pdf: (101.57 KiB) Downloaded 127 times

Melody P 2B

Also, take a look at these two diagrams uploaded on the class website!!

Reversible_Expansion.pdf: (62.74 KiB) Downloaded 115 times

Irreversible_Expansion.pdf: (38.14 KiB) Downloaded 116 times

Melody P 2B

You've got it backwards, reversible expansion does more work. And will always do more work, this is because they tend to push against more external pressure and are slow processes. Reversible processes are also ideal situations where no energy is wasted. Irreversible expansion is spontaneous/ occurs...

Melody P 2B

404982241 wrote:use the 5/2 when pressure is constant.
use 3/2 when volume is constant.

a great example is problem 8.31 in the 6th edition

Would these only be used when working with an ideal gas?

Melody P 2B

I've never had Lavelle before and I was wondering whether the questions on midterms/finals are mostly math based/problem solving or are there conceptual questions asked as well? They're mostly math based/problem solving but there are still conceptual questions, they're just worth less points./A lot...

Melody P 2B · Re: Lecture notes 2/8/19 thank you so much!!!

thank you so much!!!

Melody P 2B

I missed lecture because I had a midterm at the time, would anyone be open to sharing their notes? Please and thanks. :)

Melody P 2B

What exactly is meant by q=-w or -q=w ?

Melody P 2B

I've never had Lavelle before and I was wondering whether the questions on midterms/finals are mostly math based/problem solving or are there conceptual questions asked as well?

Melody P 2B

Yes, you'll always have to multiply the answer in $L\cdot atm$ by 101.33 J to convert into J because as previously mentioned work is typically expressed in Joules. Also, my TA was uncertain as to whether this conversion will be on our equations sheet so that's something to keep in mind.

Melody P 2B

Hi! So the reason we ended up back with w= -P\Delta V is because we were working with the DEFINITE integral which is basically V FINAL -V INITIAL which is just \Delta V Keep in mind though that this is only when pressure is constant. The derivative/integral was used for the reversible reaction examp...

Melody P 2B

Most likely not, my TA also included drawing the lewis structures to account for bonds as one of the steps when calculating using bond enthalpies.

Melody P 2B

If you're a more visual person picture the image Lavelle presented in class of a mountain. There was a blue line and a red line, both lines started and ended in the same place. However, the path each line took was different! But because enthalpy is a state property that path doesn't matter because b...

Melody P 2B

Yes! They can be, ICE tables help organize what you are given to solve equilibrium problems.

Melody P 2B

Week 3 HW should just be problems concerning Acids and Bases.

Melody P 2B

I'm certain that the Ka and Kb values will be given, we may be given pKa or pKb, but that works just as well because if we know the pKa or pKb value you can just take the antilog to find the Ka or Kb value.

Melody P 2B

Will topics not discussed in lecture, but discussed in the reading be on the test?

Melody P 2B

I just want to make sure I understand something, for the example we did in class today: Calculate the pH of solution with 0.100 M HNO2 and 0.15 M KNO2, Ka= 4.3x10^-4 The chemical equation is: HNO2(aq) + H2O (l) (eq. arrows) NO2- + H3O+ because in the chemical equation (NO2+) + (K-) + (HNO2) (eq. arr...

Melody P 2B

How many questions should we expect on the first test Week 3?

Melody P 2B

Then is there no way to determine whether an acid or base is strong by just looking at the compound itself? It's just memorization?

Melody P 2B

Then, if you were to remove some reactant would the reaction shift left? Towards the reactants to compensate for the loss?

Melody P 2B

So, when Q<K it just means the reaction isn't at equilibrium, but before it right? Because there are more reactants than products, so in order to reach K the reaction will proceed forward. And when Q>K the reaction isn't at equilibrium, but after it? Because there are more products in the product/re...

Melody P 2B

I have a follow up question regarding memorization, I did not take 14A with Lavelle but my previous prof made us memorize some more obscure compounds. Could the same be said of Lavelle?

CHEMISTRY COMMUNITY

Search found 35 matches

Re: Concentration Cells

Re: Determining the Magnitude of K

Re: Half-life Clarification

Concentration independent of the rate

Re: Slope = -k

Re: rate laws

Re: Strength of reducing agent

Re: Does anyone know if test 2 will be curved?

Re: Pt inert electrode

Re: Difference in values

Re: Test #2

6K.1 7th Edition

Re: Oxidation States

Re: Irreversible Expansions and Work

Re: Irreversible Expansions and Work

Re: When to use C=5/2R or C=3/2R

Re: Midterm [ENDORSED]

Re: Lecture notes 2/8/19

Lecture notes 2/8/19

q= -w

Re: Midterm [ENDORSED]

Re: Difference between L.atm and Joules

Re: Finding W Equations

Re: Thermo Test/Midterm

Re: enthalpy

Re: ICE boxes

Re: Homework for Week 3

Re: Ka and Kb

Re: Test 1

Weak Acid & Salt

Test 1

Re: Acids and Bases

Re: Result of Only Adding One of the Reactants

Re: Explaining Q<K and Q>K [ENDORSED]

Re: Memorization