Search found 47 matches

by Ekayana Sethi 2K
Sat Mar 17, 2018 1:09 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: delta G
Replies: 1
Views: 167

delta G

Is delta G the amount of energy free to do work(ie max work) only at standard G or any G? or is it when temp and pressure are constant?
by Ekayana Sethi 2K
Sat Mar 17, 2018 12:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration cell
Replies: 1
Views: 76

Concentration cell

for a concentration cell the E standard, Delta G standard and K will be 0 but delta G(not standard), E cell and Q will have some value if concentration is different at anode and cathode?
by Ekayana Sethi 2K
Wed Mar 14, 2018 9:55 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: ln vs log
Replies: 1
Views: 67

ln vs log

when do we use the Erxn equations containing ln and when do we use the Erxn equation using log? On contains (RT/nF)lnQ and the other one is (0.05916/n)logQ.
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:12 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: electro motive force
Replies: 1
Views: 75

electro motive force

What is electro motive force and when is potential of a cell maximum?
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:11 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: complex molecules
Replies: 8
Views: 292

complex molecules

Do complex molecules have higher or lower molar entropy than simple molecules and why?
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:10 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: thermodynamically stable
Replies: 1
Views: 83

thermodynamically stable

for a thermodynamically stable reaction what will be the signs of delta H, deltaS and delta G?
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:08 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: reversible and perfect system
Replies: 1
Views: 200

reversible and perfect system

Is a reversible system the same as a perfect system because in both deltaS system= -delta S of surrounding?
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:07 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: 2nd law
Replies: 2
Views: 223

2nd law

When asked to write the second law of thermodynamics would we explain the delta S for reversible and irreversible processes? and for a reversible does it have to be isothermal reversible for delta Stotal to be 0 or can it simply be just reversible?
by Ekayana Sethi 2K
Wed Mar 14, 2018 5:00 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: endothermic reaction.
Replies: 5
Views: 162

endothermic reaction.

IN an endothermic reactions the forward Ea is greater than the reverse Ea so will it favor reactants or products?
by Ekayana Sethi 2K
Sun Mar 11, 2018 7:30 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Reversible or irreversible?
Replies: 2
Views: 229

Reversible or irreversible?

Suppose that 50.0 g of H2O(l) at 20.0 C is mixed with
65.0 g of H2O(l) at 50.0 C at constant atmospheric pressure
in a thermally insulated vessel. Calculate S and Stot for the
process.
since delta T is 0 is it reversible or irreversible?
by Ekayana Sethi 2K
Thu Mar 08, 2018 7:54 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: to find k
Replies: 4
Views: 188

to find k

To find the k from experimental data do we have to find the k from each experiment and then find its average? Or just any one experiment to find k?
by Ekayana Sethi 2K
Thu Mar 08, 2018 4:19 pm
Forum: Zero Order Reactions
Topic: graph of 0 order
Replies: 10
Views: 351

graph of 0 order

What would the differential rate law graph of 0 order reactions look like? how would we graph [A]o against the initial rates? would it be a positive slope negative slope or a line parallel to x or y axis?
by Ekayana Sethi 2K
Wed Mar 07, 2018 11:57 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: determine K
Replies: 3
Views: 213

Re: determine K

yes I know how to calculate in terms of A but what about in terms of B?
by Ekayana Sethi 2K
Wed Mar 07, 2018 9:16 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: determine K
Replies: 3
Views: 213

determine K

For the first-order reaction A -->3 B +C, when [A]o is
0.015 mol!L"1 , the concentration of B increases to 0.018 mol!L"1
in 3.0 min. What is the rate constant for the reaction expressed
as the rate of loss of B?
by Ekayana Sethi 2K
Wed Mar 07, 2018 9:10 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: To determine k
Replies: 2
Views: 169

To determine k

2 A --> B + C, given that [A] is 0.153 mol!L"1 and that after 115 s the concentration of B rises to 0.034 mol!L"1.
In this we find At by subtracting 0.068 from Ao. but if B was a reactant and it was increasing would we add it instead of subtracting?
by Ekayana Sethi 2K
Wed Mar 07, 2018 8:22 pm
Forum: General Rate Laws
Topic: 15.13
Replies: 4
Views: 119

15.13

When 0.52 g of H2 and 0.19 g of I2 are confined to a 750.-mL reaction vessel and heated to 700. K... How come the volume of each is 0.750L. im confused is the total mixture 750ml or or each is 750ml because it says a reaction vessel so wont the total be 750ml? can somebody explain?
by Ekayana Sethi 2K
Sun Mar 04, 2018 10:53 am
Forum: First Order Reactions
Topic: half life
Replies: 3
Views: 115

half life

What does n half lives mean?
by Ekayana Sethi 2K
Sun Mar 04, 2018 10:52 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 0 order
Replies: 6
Views: 140

0 order

what does the graph of 0 order look like?
by Ekayana Sethi 2K
Sun Mar 04, 2018 10:51 am
Forum: General Rate Laws
Topic: drivations
Replies: 2
Views: 95

drivations

Will derivations be included in the test and final?
by Ekayana Sethi 2K
Thu Feb 22, 2018 9:28 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: K and Q at equilibrium
Replies: 5
Views: 169

K and Q at equilibrium

At equilibrium is K=1? wouldnt that make Estandard 0? But if Q=1 is Q also at equilibrium? Wouldnt that make Erxn=Estandard?
by Ekayana Sethi 2K
Thu Feb 22, 2018 9:23 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E rxn vs E standard at equilibrium [ENDORSED]
Replies: 2
Views: 109

E rxn vs E standard at equilibrium [ENDORSED]

I know that Erxn at equilibrium is 0. At equilibrium is Erxn=Estandard? So is Estandard also 0 at equilibrium?
by Ekayana Sethi 2K
Mon Feb 19, 2018 8:42 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: PH meter
Replies: 3
Views: 122

PH meter

can someone please explain what a PH meter is? An what all is known and what we are trying to find using the PH meter hence what is unknown?
by Ekayana Sethi 2K
Wed Feb 14, 2018 3:55 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: adibatic [ENDORSED]
Replies: 2
Views: 183

adibatic [ENDORSED]

Does q=0 always imply that deltaT is 0 making deltaU 0?
by Ekayana Sethi 2K
Wed Feb 14, 2018 2:00 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Delta U as 0
Replies: 3
Views: 142

Delta U as 0

For which different conditions is Delta U 0 making work=-q. I think deltaU is 0 in an isolated system, isothermal system, at equilibrium and when initial and final conditions are same. Is there any other time when delta U is 0? correct me if im wrong.
by Ekayana Sethi 2K
Tue Feb 13, 2018 8:11 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: change in pressure
Replies: 1
Views: 92

change in pressure

in lyndons sample midterm in 3B how do we calculate the final pressure?
by Ekayana Sethi 2K
Tue Feb 13, 2018 8:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q and change in T
Replies: 1
Views: 78

q and change in T

When reaction is endothermic at q is positive is change in T always positive implying that Tfinal is greater than T initila and the temperature was increased?
by Ekayana Sethi 2K
Mon Feb 12, 2018 10:51 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Midterm
Replies: 2
Views: 99

Midterm

for the midterm on Wednesday do we need to know how to derive any formulas because today in lecture Dr. Lavelle said derivations wont be on the test?
by Ekayana Sethi 2K
Mon Feb 12, 2018 10:48 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: comparing entropies
Replies: 1
Views: 73

comparing entropies

In which of the following phase will the substance have higher entropy?
1. gas or aq phase
2. aq or solid phase
3. aq or liquid phase
by Ekayana Sethi 2K
Mon Feb 12, 2018 6:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy vs standard
Replies: 2
Views: 112

Re: enthalpy vs standard

what if the standard reaction takes place for 2 moles? eg 2H2+o2----> 2H20. do we also divide this by 2 to find enthalpy in KJ/mol?
by Ekayana Sethi 2K
Mon Feb 12, 2018 5:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy vs standard
Replies: 2
Views: 112

enthalpy vs standard

what is the difference between enthalpy of a reaction and the standard enthalpy of reaction? for which one do we have to divide it by moles to get it for per mole?
by Ekayana Sethi 2K
Sat Feb 10, 2018 11:33 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: entropy of irreversible and reversible reactions.
Replies: 2
Views: 93

entropy of irreversible and reversible reactions.

Are the entropies of irreversible and reversible reactions the same? how are they related?
by Ekayana Sethi 2K
Sat Feb 10, 2018 11:30 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: system vs surroundings
Replies: 6
Views: 276

system vs surroundings

if a beaker has a reaction taking place the system is the reaction but is the surroundings the beaker or the atmosphere? also if the beaker was immersed in a water bath the system will still be the reaction but what will the surroundings be? Is it the water bath or the beaker?
by Ekayana Sethi 2K
Sat Feb 10, 2018 11:28 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed vs isolated
Replies: 11
Views: 446

closed vs isolated

Are the pressures and volumes constant in a closed and isolated system?
by Ekayana Sethi 2K
Sat Feb 10, 2018 11:27 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.117
Replies: 2
Views: 135

8.117

what is the delta(n)? I thought it was 2 but the solutions manual says it is 2/3 why is that?
by Ekayana Sethi 2K
Sun Feb 04, 2018 10:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: change in entropy with change in temperature
Replies: 2
Views: 86

change in entropy with change in temperature

is deltaS=n*R*ln(T2/T1) or deltaS=n*C*ln(T2/T1)? because the book uses both. Also when do we know which one to use when?
by Ekayana Sethi 2K
Sat Feb 03, 2018 6:17 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: syllabus
Replies: 4
Views: 149

syllabus

What chapters will be covered in the coming midterm? and will the new chapter that professor Lavelle teaches next week be included in the syllabus?
by Ekayana Sethi 2K
Fri Feb 02, 2018 4:45 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Midterm
Replies: 6
Views: 206

Midterm

What exact parts of chapter 11 do we need to read through for the coming midterm?
by Ekayana Sethi 2K
Thu Jan 25, 2018 7:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: change in enthalpy
Replies: 2
Views: 100

change in enthalpy

is delta(H)=delta(U)-delta(n)*R*T or delta(H)=delta(U)+delta(n)*R*T? Also is work -P*delta(V) or +P*delta(V)?
by Ekayana Sethi 2K
Thu Jan 25, 2018 5:40 pm
Forum: Phase Changes & Related Calculations
Topic: enthaply
Replies: 3
Views: 112

enthaply

the enthalpy of vaporization is deltaH=Hvapor-Hliquid. What is the difference between deltaH and just H and where do we find the values for H(NOT deltaH!) of vapor or liquid of a substance?
by Ekayana Sethi 2K
Mon Jan 22, 2018 4:31 pm
Forum: Calculating Work of Expansion
Topic: expansion work
Replies: 2
Views: 92

expansion work

in expansion work the volume increases. does the pressure change or is it constant at 1 atm?
by Ekayana Sethi 2K
Sun Jan 21, 2018 9:10 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open System
Replies: 7
Views: 257

Re: Open System

to change internal energy you can add or subtract matter to or from the system, do work on it or make it do work and add heat or subtract heat from it.
since it is specifically asking how to increase internal energy it can be done by adding heat to it, adding matter and doing work on it.
by Ekayana Sethi 2K
Sun Jan 21, 2018 9:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 130

bond enthalpies

In lecture Professor Lavelle said something about converting all products and reactants into gas form to use bond enthalpies. I did not understand what he meant. How do we convert something into gas?
by Ekayana Sethi 2K
Sun Jan 21, 2018 9:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: delta n
Replies: 3
Views: 428

delta n

How do we calculate delta n for a given equation? Is it number of moles of the products minus the number of moles of the reactants or the opposite? and do we include solid and liquid products and reactants or just gasses? and what if delta n is 0?
by Ekayana Sethi 2K
Sat Jan 20, 2018 10:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: standard enthalpy of formation [ENDORSED]
Replies: 4
Views: 147

standard enthalpy of formation [ENDORSED]

I'm a little confused about the difference between enthalpy of formation and enthalpy of reaction? could someone explain please?
by Ekayana Sethi 2K
Sun Jan 14, 2018 5:30 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: living plant
Replies: 4
Views: 160

living plant

Is a living plant an open, closed or isolated system? because a human being is. What about a dead plant?
by Ekayana Sethi 2K
Sun Jan 14, 2018 5:23 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heating curves
Replies: 1
Views: 72

Heating curves

In the book it says that "The steeper the slope of a heating curve, the lower is the heat capacity." why is this true? It also says that "The slope of a heating curve is steeper for a phase with a low heat capacity than for one with a high heat capacity." could someone explain th...
by Ekayana Sethi 2K
Thu Jan 11, 2018 7:52 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 785973

Re: Post All Chemistry Jokes Here

Why did the white bear dissolve in water?
Because it was polar!

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