Search found 32 matches

by JacobHershenhouse3G
Sat Mar 16, 2019 4:21 pm
Forum: Administrative Questions and Class Announcements
Topic: LYNDON'S PORK RAMEN REVIEW
Replies: 37
Views: 2657

Re: LYNDON'S PORK RAMEN REVIEW

Lyndonthis is so helpful, thanks
by JacobHershenhouse3G
Sat Mar 16, 2019 2:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reduction/Concentration cells
Replies: 1
Views: 35

Re: Reduction/Concentration cells

Because at a higher concentration the electrical potential is higher (E) so you can reasonably state that the higher E is the cathode if you want your Ecell to be positive.
by JacobHershenhouse3G
Sat Mar 16, 2019 2:23 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: k & K
Replies: 18
Views: 390

Re: k & K

K is the equilibrium constant and kr is the rate constant, symbolizing different constant values with different meanings, applied in different equations but they are related. K is equal to the overall forward rate constant over the reverse rate constant because at equilibrium the forward and reverse...
by JacobHershenhouse3G
Fri Mar 08, 2019 4:31 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Reaction mechanisms
Replies: 3
Views: 79

Re: Reaction mechanisms

Think about the steps of a given reaction being considered fast or slow. The two contingencies are at either ends of the spectrum, just like how acids and bases can be strong or weak. So, the rate of the whole reaction is determined mostly by the slowest step of the reaction because the fast step(s)...
by JacobHershenhouse3G
Fri Mar 08, 2019 4:24 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6th edition 14.35
Replies: 3
Views: 85

Re: 6th edition 14.35

It seems that you have the right idea and the book may have a typo. the oxidation state on a lone ion is the charge so it makes sense that In3+ is reduced to In2+ with the gain of an electron.
by JacobHershenhouse3G
Fri Mar 08, 2019 4:21 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E° is 0 for Concentration Cells
Replies: 3
Views: 84

Re: E° is 0 for Concentration Cells

You just have to think about it in terms of the anode and cathode and keeping in mind that the material is the same at both. So the sum of the standard potentials cancel because they are equal and opposite in magnitude.
by JacobHershenhouse3G
Thu Feb 28, 2019 5:54 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Max work
Replies: 2
Views: 68

Re: Max work

Think about gibbs free energy as the energy still availible (non-expansion) for the system to do work. This definition is why gibbs free energy is a useful concept and explains spontaneity.
by JacobHershenhouse3G
Thu Feb 28, 2019 5:27 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Standard cell potential of H
Replies: 2
Views: 63

Re: Standard cell potential of H

H is set to be an arbitrary zero because the cell potential is a different between the the voltage of two points. This way we can compare cell potential of different setups. Its all relative
by JacobHershenhouse3G
Thu Feb 28, 2019 5:25 am
Forum: Van't Hoff Equation
Topic: Constants
Replies: 3
Views: 197

Re: Constants

When you're solving for k at different temperatures, you're going to be using standard enthalpy and entropy values, so these dont change based on temperature. Thinking back to the first midterm though, we can remember that k does depend on temperature so that's how this concept can be applied to the...
by JacobHershenhouse3G
Thu Feb 28, 2019 5:23 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Potential
Replies: 2
Views: 47

Re: Cell Potential

I don't think we are expected to know extraneous values, but you should know how to use them in equations/apply them and what they mean when given.
by JacobHershenhouse3G
Tue Feb 19, 2019 12:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: K=e^lnK
Replies: 4
Views: 100

Re: K=e^lnK

e is an irrational number in math that has the special property: de^x=e^x (derivative equals the value). As well, natural log is the log base e of x so it applies here that anything set to the power of its own log "cancels" and leaves you with the value of the log! Hope this helps :)
by JacobHershenhouse3G
Tue Feb 19, 2019 12:41 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Entropy at 0 K
Replies: 6
Views: 266

Re: Entropy at 0 K

Its possible to have 0 entropy, when there is no degeneracy at absolute zero. At higher temperatures, vibrational, translational, transitional entropy are spontaneous and add to the total entropy. This is why we have been considering entropy at 0 K because then the S= K In(W) holds true (does not in...
by JacobHershenhouse3G
Tue Feb 19, 2019 12:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs free energy
Replies: 7
Views: 115

Re: Gibbs free energy

You can think about Gibbs free energy as a conglomeration of enthalpy, temperature, and entropy because they are all related to energy and the amount of work a system can do, so the GFE equation brings them all together. Hope this helps :)
by JacobHershenhouse3G
Sun Feb 10, 2019 2:34 pm
Forum: Calculating Work of Expansion
Topic: Integrals
Replies: 3
Views: 65

Re: Integrals

We will probably not be asked to derive equations, I would focus on the practice homework problems dealing with thermochemistry instead of studying the proof.
by JacobHershenhouse3G
Sun Feb 10, 2019 2:32 pm
Forum: Calculating Work of Expansion
Topic: Work equations
Replies: 2
Views: 59

Re: Work equations

Big difference! w is representative of work, while W represents degeneracy. They are each used in various equaitons we've looked at in class; work is more related to energy, while degeneracy is closely tied to entropy. Hope this helps! :)
by JacobHershenhouse3G
Tue Feb 05, 2019 8:44 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 139
Views: 84001

Re: Advice from a Medical Student [ENDORSED]

As a pre med student, this makes me feel much more confident in this course and in the pre med process. Thank you for sharing your experience and I will definitely learn from it!
by JacobHershenhouse3G
Tue Feb 05, 2019 8:39 pm
Forum: Calculating Work of Expansion
Topic: work done by system or on system
Replies: 3
Views: 87

work done by system or on system

I know that deltaU= q + w but how do you differentiate if work and temperature is applied to or by the system from the surroundings? I seem to keep messing up signs and would like some clarification.
by JacobHershenhouse3G
Tue Feb 05, 2019 8:36 pm
Forum: Calculating Work of Expansion
Topic: Pressure Units
Replies: 7
Views: 124

Pressure Units

Hello, I'm just wondering if we should know all of the pressure unit conversions for the midterm/ if it will be given on the exam. Some of the homework problems include conversion steps so I'm not sure.
by JacobHershenhouse3G
Wed Jan 30, 2019 6:43 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 4
Views: 71

Re: Hess's Law

The thing that works best for me with solving problems like this is to think about it like solving a puzzle. Each equation that is given gives you one piece of what you need to find your answer (or else it wouldnt have been a given). So, looking at each one, find the part thats important and move to...
by JacobHershenhouse3G
Wed Jan 30, 2019 6:35 pm
Forum: Ideal Gases
Topic: kc vs kp
Replies: 16
Views: 446

Re: kc vs kp

Kc and Kp are not interchangeable. Kc is found and can only be used in relation to concentrations and Kp is related to the partial pressures of products and reactants. Hope this helps!
by JacobHershenhouse3G
Wed Jan 30, 2019 6:34 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pKa vs. pH
Replies: 15
Views: 440

Re: pKa vs. pH

Don't let yourself be confused by similar notation because they mean dramatically different things. p just means -log, so in this case you are taking the negative log of a constant and of a concentration, therefore it is evident that the interpretation of these numbers mean different things. Both va...
by JacobHershenhouse3G
Wed Jan 23, 2019 1:43 pm
Forum: Ideal Gases
Topic: Units for concentration
Replies: 5
Views: 90

Re: Units for concentration

Yes! These units are equivalent, no stoichiometry needed! Molarity is more often used because it's quicker to write M compared to writing out mol*L^-1 every time. Hope this helps!
by JacobHershenhouse3G
Wed Jan 23, 2019 1:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% rule and % ionization
Replies: 2
Views: 63

Re: 5% rule and % ionization

Simply use the equation %deprot= [H3O+]/initial[reacting acid] or %prot [OH-]/initial[reacting base]. The 5 % rule is a check on if the change (-x) to the initial concentration of the given acid or base is significant or negligible (if negligible, then the simplification of our k equation is alright...
by JacobHershenhouse3G
Wed Jan 23, 2019 1:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.57
Replies: 1
Views: 61

Re: 6th edition, 12.57

Right, so in this problem, you have to work at it from both ends. First, you must write out the full acidic reaction of having HClO2 in water (HClO2 + H2O == ClO2- + H3O+). From here, you can use given variables to find the equilibrium concentrations of the products from the pH (10^-pH=[H30+]=[ClO2-...
by JacobHershenhouse3G
Wed Jan 23, 2019 1:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Number 93 Ch.11
Replies: 1
Views: 45

Re: Number 93 Ch.11

You must use the context of the problem (your knowns) to determine if the k or kc value is applicable in your problem solving process. K is related to the pressure of a certain gas (bar, torr, pascal, atm etc.), while kc is used when concentrations are given for a gas or aqueous solution (M, mol/L, ...
by JacobHershenhouse3G
Wed Jan 23, 2019 1:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Polyprotic acids
Replies: 1
Views: 46

Re: Polyprotic acids

Depending on how small the following ka's are, you may be able to approximate by only solving the equilibrium concentrations of the first ka, but only if the ka's are very small and you know the difference in equilibrium concentrations will be negligible. Otherwise, if you are told to go through the...
by JacobHershenhouse3G
Mon Jan 14, 2019 8:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: effect on equilibrium by changing volume
Replies: 2
Views: 59

Re: effect on equilibrium by changing volume

Remember that Q is the constant at any given point in time and has applications that dont involve the changing of equilibrium concentrations. The important thing to note is that BOTH K and Q change when you alter volume or temperature (to reflect the change in equilibrium concentration values). So, ...
by JacobHershenhouse3G
Mon Jan 14, 2019 1:08 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing Temperature
Replies: 4
Views: 108

Re: Changing Temperature

Think back to the ideal gas law PV=nRT. Pressure and volume are directly related Using what we know about exothermic and endothermic reactions, we can determine if the reaction shifts left or right but whats of superlative importance is that you know that temperature DOES change equilibrium. Think r...
by JacobHershenhouse3G
Mon Jan 14, 2019 1:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: ICE Table [ENDORSED]
Replies: 3
Views: 93

Re: ICE Table [ENDORSED]

Be careful here! You are using concentration values, not molar values when you are plugging values into the ICE table as you solve for x. This is because the end goal is the equilibrium concentrations of reactants and products, not the number of moles. Yet, you have the right idea using the stoichio...
by JacobHershenhouse3G
Sat Jan 12, 2019 1:59 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: compression vs pressure
Replies: 6
Views: 283

Re: compression vs pressure

Yes! Kc will change if you alter volume (compression), but be careful because Kc does not change when you change pressure in the case that, instead of changing the volume to affect pressure, you change pressure by adding or removing inert gas from the system ({C=[num of moles]/[Volume]} concentratio...
by JacobHershenhouse3G
Sat Jan 12, 2019 1:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice table
Replies: 4
Views: 68

Re: ice table

The reason you put ...-2x, -x, +x, +2x... in the change box of your ice table is because we know that the change in concentration from initial state to final state (equilibrium) is consistent across molecules and proportional to the molar ratio of reactants and products (the coefficients), and we kn...
by JacobHershenhouse3G
Sat Jan 12, 2019 1:33 am
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1191

Re: Q and K [ENDORSED]

Yes K and Q have the same formula. More importantly, though, they represent different things that, when compared, yield answers to the direction of the reaction at a certain point in time. K=constant (at equilibrium only), Q=constant (at any point in time throughout the reaction). Each specific valu...

Go to advanced search