Search found 218 matches

by 004253593
Sun Mar 16, 2014 11:47 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis/Trans for Cyclohexane
Replies: 5
Views: 738

Re: cyclohexane

by the same side- i mean if you draw out the chair conformation- and the 2 substituents are both on the top half of the drawing-
by 004253593
Sun Mar 16, 2014 11:45 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: final 2012 1b
Replies: 8
Views: 1029

Re: final 2012 1b

"you can say that, if you have the q for the reaction at lower temp. (like this particular example)
So if you know the q for the reaction at higher temp instead,"


- what do you mean- lower temperature than what???
by 004253593
Sun Mar 16, 2014 11:42 am
Forum: *Cycloalkenes
Topic: Final 2013 6a Numbering a hexene
Replies: 8
Views: 2263

Re: Final 2013 6a

so double bond gets priority- right
by 004253593
Sun Mar 16, 2014 11:41 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis/Trans for Cyclohexane
Replies: 5
Views: 738

Re: cyclohexane

so even if they are on the same side- but one is pointing up and one is pointing down- its trans?
by 004253593
Sun Mar 16, 2014 11:38 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: 2012 8a
Replies: 4
Views: 824

Re: 2012 8a

then how do you know when to overlap the 2 main groups??
by 004253593
Sun Mar 16, 2014 11:37 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: final 2012 1b
Replies: 8
Views: 1029

Re: final 2012 1b

so if you don't have the enthalpies- you always just cool the reactants, find kj of reactant, and then heat the products??
by 004253593
Sun Mar 16, 2014 11:31 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 2011 2
Replies: 3
Views: 589

Re: 2011 2

oh- so the H2 cancelled out means that its accepting the electrons
by 004253593
Sun Mar 16, 2014 11:29 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2009 4e
Replies: 5
Views: 983

Re: final 2009 4e

and you find ph by doing 10^-(concentration of H) right?
by 004253593
Sun Mar 16, 2014 11:28 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis/Trans for Cyclohexane
Replies: 5
Views: 738

Cis/Trans for Cyclohexane

how can you tell if a cyclohexane is cis or trans?

is it if its on the same side? or is it cis if the axial and equatorial are both pointing in the same direction???
by 004253593
Sun Mar 16, 2014 11:27 am
Forum: *Alkanes
Topic: 2013 6A
Replies: 2
Views: 533

2013 6A

Question 6A on the Winter 2013 Final Exam states: "Carotenes are usually orange or yellow in color and play a role in photosynthesis by transmitting the light energy they absorb from chlorophyll. Part of a carotene molecule is below. Name it, identify (circle) the sp2 carbon atoms, and give its...
by 004253593
Sun Mar 16, 2014 11:25 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: 2012 8A
Replies: 2
Views: 652

2012 8A

Question 8A on the Winter 2012 Final Exam states:

"Draw a Newman projection of 1 -iodopropane looking down the C1-C2 bond with a dihedral angle of +120 degrees for the ICCC dihedral angle."


8A would be eclipsed when the CH3 is behind the I?
by 004253593
Sat Mar 15, 2014 10:06 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: 2012 8a
Replies: 4
Views: 824

2012 8a

Question 8A on the Winter 2012 Final Exam states: "Draw a Newman projection of 1 -iodopropane looking down the C1-C2 bond with a dihedral angle of +120 degrees for the ICCC dihedral angle." In the answer key it says it needs to be eclipsed. Does that mean that 120 degrees is eclipsed? Also...
by 004253593
Sat Mar 15, 2014 9:33 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 2011 2
Replies: 3
Views: 589

2011 2

where do get the 3 from ( how do you know how to multiply it by 3)
by 004253593
Sat Mar 15, 2014 9:28 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: final 2012 1b
Replies: 8
Views: 1029

final 2012 1b

how do you know to heat the products and cool the reactants?
by 004253593
Fri Mar 14, 2014 9:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2009 4e
Replies: 5
Views: 983

Re: final 2009 4e

how do you know to take out H- is that because you can only find pH with H+?
by 004253593
Fri Mar 14, 2014 6:59 pm
Forum: *Alkenes
Topic: final 2009 7b
Replies: 1
Views: 401

final 2009 7b

how do they get z-octadec9-enoic acid

why is it 9? i thought it was 7?
by 004253593
Fri Mar 14, 2014 6:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2009 4e
Replies: 5
Views: 983

final 2009 4e

at what pH would the concentrations listed above be in equilibrium at 298k?

where did they get the 1.67 from???
by 004253593
Wed Mar 12, 2014 9:08 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2012 3
Replies: 9
Views: 1694

Re: 2012 3

what about if you want to find the kb value is it also electrolysis?
also you know for ka you have to do the square root of K

do you also have to do that for kb?
by 004253593
Wed Mar 12, 2014 8:31 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2012 3
Replies: 9
Views: 1694

Re: 2012 3

will the problem tell us its electrolysis? or how would we recognize an electrolysis problem?
by 004253593
Wed Mar 12, 2014 8:29 pm
Forum: Calculating Work of Expansion
Topic: expansion
Replies: 1
Views: 435

expansion

how much work does 100g of water do when it freezes at 0 degrees and pushes back the plastic wall of a pipe that exerts an opposing pressure of 1070 atm? density of water i 1g/cm^3 and density of ice is .92g/cm^3
by 004253593
Wed Mar 12, 2014 8:13 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: water
Replies: 1
Views: 306

water

how will adding water to anode compartment effect cell potential? also adding water to cathode?
by 004253593
Sun Mar 09, 2014 8:19 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2012 3
Replies: 9
Views: 1694

Re: 2012 3

thanks-
when do we want the overall E to be negative?
by 004253593
Sun Mar 09, 2014 12:13 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Angle Strain
Replies: 4
Views: 970

Re: Angle Strain

how do you relate degree of strain to size of a ring?

is it the more carbons- the less strain?
by 004253593
Sun Mar 09, 2014 12:11 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: dihedral angle
Replies: 1
Views: 619

dihedral angle

how do you figure out the dihedral angle?
also why does potential energy depend on dihedral angle?

also how do you determine the relative conformational stabilities of di-substitued and try-subsituted cyclohexanes?
by 004253593
Sun Mar 09, 2014 10:20 am
Forum: *Electrophiles
Topic: F
Replies: 1
Views: 459

F

is F an electrophile and F- a nucleophile?
only if it has negative charge on F will it be nucleophile?
by 004253593
Sat Mar 08, 2014 5:27 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2012 3
Replies: 9
Views: 1694

2012 3

how do you now if CrCl3 or CuSo4 is an anode/ cathode? how can you tell which is which??
by 004253593
Sat Mar 08, 2014 3:42 pm
Forum: *Alkanes
Topic: final 2010 7e
Replies: 1
Views: 494

final 2010 7e

Question 7E on the Winter 2010 Final Exam states: "Give the IUPAC names for: propylamine ________________ 1-propanamine isopropylamine ______________2-propanamine methyl ethyl amine ____________N-methylethanamine trimethylamine _______________N, N-dimethylmethanamine" how do you give upac ...
by 004253593
Sat Mar 08, 2014 3:28 pm
Forum: *Cyclopentanes
Topic: final 2007 6b
Replies: 6
Views: 2360

Re: final 2007 6b

do molecules with more carbons in a ring have more or less ring strain than molecules with less carbons in a ring?

cause on 4c on test2011 it stays that the ring strain of the cyclooctane has higher ring strain than cyclohexane-
by 004253593
Sat Mar 08, 2014 3:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 7
Views: 810

Re: final 2008 3.

that makes so much for sense!
by 004253593
Sat Mar 08, 2014 3:18 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 4
Views: 691

Re: final 2008 3.

also i undestand in this problem which is the anode and the cathode- i don't understand what is the electrode for both the anode and cathode
by 004253593
Sat Mar 08, 2014 3:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 4
Views: 691

Re: final 2008 3.

then how come on the last problem of the final. they made the cell potential negative instead of positive- i don't understand why
by 004253593
Sat Mar 08, 2014 3:14 pm
Forum: *Cyclopentanes
Topic: final 2007 6b
Replies: 6
Views: 2360

final 2007 6b

Question 6B on the Winter 2007 Final Exam states: "Draw a structure which clearly shows the most stable conformation for 1-ethyl-1-isopropylcyclohexane." i know its a chair but how do you know which to put in axial in which to put in equatorial. also is the molecular formula for isopropyl ...
by 004253593
Sat Mar 08, 2014 3:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2010 final 1b
Replies: 6
Views: 798

Re: 2010 final 1b

but they don't give us the specific heat capacity of copper. how would we figure it out without that?
by 004253593
Sat Mar 08, 2014 2:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 7
Views: 810

Re: final 2008 3.

thanks! It also asks which electrode in each cell is the anode
for pb it says Pb (s) and I understand that because its a solid. but for Cu its the standard hydrogen electrode- why isn't it the Cu(s)????
by 004253593
Sat Mar 08, 2014 12:11 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2013 final
Replies: 3
Views: 616

2013 final

2Fe + 2h20 + 02 - 2Fe(OH)2
how do you know that n=4???
by 004253593
Fri Mar 07, 2014 9:02 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: drawing
Replies: 5
Views: 1087

Re: drawing

do we also have to know all the angles for each drawing? also do we have to memorize the energies for each conformation (like know the torsional strain for a specific conformation)??
by 004253593
Fri Mar 07, 2014 4:16 pm
Forum: First Order Reactions
Topic: final 2010 5a
Replies: 1
Views: 420

final 2010 5a

how do you find the k? if you only have the concentration but not the rate???
by 004253593
Fri Mar 07, 2014 3:24 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2010 final 1b
Replies: 6
Views: 798

2010 final 1b

on heating from 10 to 20 celsius which requires mor heat?
its water

which requires more heat
breaking c-c single bonds or melting 1 mole of ice
its breaking bond

how do you know these things??
by 004253593
Thu Mar 06, 2014 9:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 4
Views: 691

final 2008 3.

b. which electrode in each cell is the anode?

how do you figure this out?

for pb its pb (s)
for cu cell its the standard H electrode
by 004253593
Thu Mar 06, 2014 9:32 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: final 2007 3c
Replies: 2
Views: 460

final 2007 3c

is this type of fuel cell thermodynamically feasible?
the answer is yes

what makes something thermodynamically feasible?????
by 004253593
Thu Mar 06, 2014 9:29 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: drawing
Replies: 5
Views: 1087

drawing

do we have to know how to draw everything- like all the structures (boat, chair, ect. knowing where all the H's go)
how do you know which newman projection is the most stable for a particular molecule?
by 004253593
Thu Mar 06, 2014 9:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 7
Views: 810

final 2008 3.

what is the E (Knot) of each cell at 298?

how do you find the E knot of the Pb and Cu at a certain temperature?
do they automatically just become positive???
by 004253593
Wed Mar 05, 2014 9:22 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: 3.15
Replies: 3
Views: 712

3.15

1,1, bromochlorocyclohexane has a preference for 1 conformation, draw it and draw it undergoing a ring flip

how do you know which preference it has?
is it a chair????
by 004253593
Wed Mar 05, 2014 8:46 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: steric and torsional strain
Replies: 1
Views: 539

steric and torsional strain

how can you tell without drawing it - if it has torsional or steric strain
by 004253593
Wed Mar 05, 2014 4:41 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: staggered v. eclipsed
Replies: 3
Views: 3087

staggered v. eclipsed

http://web.tock.com/kalee/chem32/groupT/ethane.gif

on the top 2 pictures- how do you know which one is eclipsed or staggered- i don't understand how you can differentiate them
by 004253593
Sat Mar 01, 2014 4:53 pm
Forum: *Alkanes
Topic: 33
Replies: 1
Views: 378

33

name of the reaction mechanism for reaction CH3Br + OH - CH3OH + Br-
its bimolecular nucleophili substitution reaction SN2.

do you know that just by looking at it, or do you have to draw a lewis structure?
by 004253593
Sat Mar 01, 2014 4:51 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: 30. orgo
Replies: 1
Views: 526

30. orgo

30. the Ea in the organic reaction is 125 kj/mol. will reaction occur at room temperature?
the answer is no,
but why??? how do you know?
by 004253593
Sat Mar 01, 2014 2:40 pm
Forum: *Alkanes
Topic: order
Replies: 2
Views: 439

order

in class on friday he said the name of something was dimethyl ethyl cyclohexane.
I thought its supposed to be in alphabetical order and be ethyl dimethyl cyclohexane (cause I thought the di in front didn't count)
by 004253593
Sun Feb 23, 2014 8:26 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm grading
Replies: 3
Views: 1228

Re: Midterm grading

where are the detailed solutions- I can't find them?
by 004253593
Fri Feb 21, 2014 10:15 pm
Forum: Zero Order Reactions
Topic: zero order
Replies: 1
Views: 608

zero order

randome question i found

a zero order reaction is 40% complete in 200.s. how long does it rake for 15% completion (use (A)0= .100M
by 004253593
Fri Feb 21, 2014 9:26 pm
Forum: Second Order Reactions
Topic: concentration doubles
Replies: 3
Views: 47854

Re: concentration doubles

thanks- does temperature also affect the orders?
by 004253593
Fri Feb 21, 2014 9:05 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: graphs
Replies: 4
Views: 2115

graphs

how do you know just by looking at a graph if its spontaneous?
how do you know just by looking at a graph if it favors the reactant or product?
how do you know just by looking at a graph if its thermodynamically unfavorable?
by 004253593
Fri Feb 21, 2014 8:43 pm
Forum: Second Order Reactions
Topic: concentration doubles
Replies: 3
Views: 47854

concentration doubles

what happens to a second order reaction as the concentration doubles?

are all the orders dependent on concentration? zero isn't right?
what else are the order dependent on?
by 004253593
Fri Feb 21, 2014 8:41 pm
Forum: General Rate Laws
Topic: linear
Replies: 3
Views: 494

Re: linear

i am a little confused with some parts of your answer
like this- are you saying its linear or not??

(e) k vs t
Lnk = -Ea/(RT) + Ln[A] = -(Ea/R)(1/T) + Ln[A]

NOT LINEAR: Lnk vs 1/T would be linear
by 004253593
Thu Feb 20, 2014 1:33 pm
Forum: General Rate Laws
Topic: linear
Replies: 3
Views: 494

linear

how do you know if something is linear under certain conditions?
like in question 103 when it asks a bunch of scenarios- like if 1/A is it linear in first condition, or half life and temperature if its linear??
by 004253593
Thu Feb 20, 2014 1:00 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 14.59
Replies: 2
Views: 473

Re: 14.59

Thanks!
by 004253593
Thu Feb 20, 2014 12:59 pm
Forum: *Enzyme Kinetics
Topic: 14.85
Replies: 2
Views: 699

14.85

how do you draw a proposed structure for the activated complex

1. CH3CHO- CH3 + CHO
2. r=k (I2)(Ar) 2I- I 2
3. O2 + NO - NO2 + O
by 004253593
Wed Feb 19, 2014 4:54 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 14.59
Replies: 2
Views: 473

14.59

the rate constant for a first order redaction is .76 s-1 at 1000K and .85 s-1 at 1030K. calculate activation energy

how are you supposed to know which is k and which is k' ????
by 004253593
Wed Feb 19, 2014 3:15 pm
Forum: General Rate Laws
Topic: reaction rates
Replies: 3
Views: 532

Re: reaction rates

If there is no reverse reaction- it is usually a slow step.
the fast reactions, also have reverse reactions.

thats just one clue
by 004253593
Wed Feb 19, 2014 3:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: intermediates
Replies: 5
Views: 639

Re: intermediates

The throughs represent the transition states. They have the most energy right? Do the intermediates also have a lot of energy?
by 004253593
Sun Feb 16, 2014 2:36 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: intermediates
Replies: 5
Views: 639

Re: intermediates

Thanks! the larger the peak- it means the more activation energy needed right? Also the higher the peak- the more likely to have a catalyst right?
by 004253593
Sun Feb 16, 2014 2:35 pm
Forum: General Rate Laws
Topic: catalyst v. intermediate
Replies: 3
Views: 826

Re: catalyst v. intermediate

there is one problem that I saw where there is an intermediate and a catalyst- in a multistep reaction
you can see both the catalyst and the intermediate in the equations- but they both get crossed out
by 004253593
Sat Feb 15, 2014 11:46 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: intermediates
Replies: 5
Views: 639

intermediates

how can you tell by looking at a graph, how many intermediates there will be??
by 004253593
Sat Feb 15, 2014 10:00 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: radical chain initiating
Replies: 1
Views: 392

radical chain initiating

what does radical chain initiating mean? and does it occur when the concentration is squared?
by 004253593
Sat Feb 15, 2014 9:15 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: R
Replies: 1
Views: 358

R

what does the R stand for in the activation energy equation? How do you find its value?
by 004253593
Sat Feb 15, 2014 8:55 am
Forum: General Rate Laws
Topic: catalyst v. intermediate
Replies: 3
Views: 826

catalyst v. intermediate

how can you determine which is the intermediate and which is the catalyst in a reaction?
by 004253593
Wed Feb 12, 2014 3:36 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: combustion
Replies: 2
Views: 489

combustion

is q always negative for combustion??
by 004253593
Tue Feb 11, 2014 9:52 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 13.103
Replies: 3
Views: 553

Re: 13.103

yeah for this one thats not the case- because reversing it gives you a negative number
by 004253593
Tue Feb 11, 2014 8:38 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 13.103
Replies: 3
Views: 553

13.103

how do you know that F2 +H+ +2e- - 2HF is the anode????
by 004253593
Tue Feb 11, 2014 8:33 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 13.41c
Replies: 3
Views: 478

Re: 13.41c

why is it squared?
by 004253593
Tue Feb 11, 2014 8:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: adding water
Replies: 3
Views: 2031

adding water

what would be the effect on the cell potential if you added water to the anode compartment??
or the cathode??
by 004253593
Tue Feb 11, 2014 5:41 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 13.41c
Replies: 3
Views: 478

13.41c

where does the random 1.101325^2 come from??
by 004253593
Tue Feb 11, 2014 5:28 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: ka2
Replies: 1
Views: 365

ka2

for lnk is K product/reactant or is it anode/cathode???
by 004253593
Tue Feb 11, 2014 5:08 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 13.39b
Replies: 1
Views: 391

Re: 13.39b

i saw the same thing! I think its a mistake!
by 004253593
Tue Feb 11, 2014 5:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 13.39
Replies: 1
Views: 255

13.39

isn't the number of moles for H2/H+ 2? in the answers its only one??
by 004253593
Sun Feb 09, 2014 6:25 pm
Forum: Calculating Work of Expansion
Topic: bomb calorimeter
Replies: 1
Views: 458

bomb calorimeter

so if something occurs in a bomb calorimeter and then asks what the delta U is for reaction. i know w =0, but would q become negative- cause of the surrounding/system idea??
by 004253593
Sun Feb 09, 2014 6:08 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 3/2
Replies: 5
Views: 724

Re: 3/2

thanks so much! so whenever it is that equation with the C we use 3/2 when its a constant volume?
by 004253593
Sun Feb 09, 2014 6:06 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: residual entropy
Replies: 1
Views: 923

residual entropy

why is this the order of increasing residual entropy???

C2H2<HF<BCl2H

i would think that HF is the least??? so confused!
by 004253593
Sun Feb 09, 2014 5:22 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 3/2
Replies: 5
Views: 724

Re: 3/2

I know that part. But for only some questions do people put it in. like for entropy- only sometimes is 3/2 put in. Is it only when we have two temperatures that we are given? because when we are given two volumes- they never put 3/2R
by 004253593
Sun Feb 09, 2014 5:19 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: dissolve
Replies: 1
Views: 446

dissolve

how do you predict if a metal will dissolve in a solution?

does that mean- dissolve would that be oxidation or reduction?
by 004253593
Sun Feb 09, 2014 5:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: fossil fules
Replies: 1
Views: 377

fossil fules

Understand the environmental impact of burning fossil fuels and use of alternative fuels

what do we have to know for this?
by 004253593
Sun Feb 09, 2014 8:58 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: molar entropy
Replies: 2
Views: 835

Re: molar entropy

yeah thats what i thought to but on midterm 2013 number 5B.
they say that the increasing molar entropy is
CH3F<CH2F2<CHF3<CF4
by 004253593
Sun Feb 09, 2014 8:53 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: cell potential
Replies: 4
Views: 1247

Re: cell potential

how would you Predict the effect of changes in concentration of reactants and products on the cell potential
by 004253593
Sun Feb 09, 2014 8:49 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 3/2
Replies: 5
Views: 724

3/2

when do you use the 3/2 R in the entropy equations??
by 004253593
Sun Feb 09, 2014 8:46 am
Forum: Balancing Redox Reactions
Topic: oxidize or reduce?
Replies: 2
Views: 728

oxidize or reduce?

Can lead produce zinc metal from aqueous zinc sulfate under standard conditions?

what is this question asking? is it asking if lead can be oxidized or reduced?
by 004253593
Sat Feb 08, 2014 8:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: winter 2013 3
Replies: 1
Views: 365

winter 2013 3

heating the water they do the q=mcchangeT + Hvap of water
for the Hvap of water they get 2259J/g- where do they get that number- i thought it was 40.7kj/mol??
by 004253593
Sat Feb 08, 2014 8:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: winter 2010 5
Replies: 2
Views: 367

winter 2010 5

calculate free energy at 25 for combustion of 1 mol of glucose change in G=change in H- T change in S they give you change in H (subscript C)= -2808kj/mol what does the subscript stand for in the answer they use this as the change in H, but i thought you have to do products- reactants. so the H of H...
by 004253593
Sat Feb 08, 2014 8:16 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: molar entropy
Replies: 2
Views: 835

molar entropy

how do you know the order of increasing molar entropy for the following gases

CH3F CF4 CH3F CH2F2
by 004253593
Sat Feb 08, 2014 10:55 am
Forum: Balancing Redox Reactions
Topic: 7A winter midterm 2009
Replies: 2
Views: 661

7A winter midterm 2009

balance redox reaction that occurs in acid

Cr2O7^2- + H2(g) - Cr^3+ (aq)

i understand that you need to add H+

but when you balance how do you know what coefficient to put in front of the H2 and how many to put in front of the H+, because they are both H's
by 004253593
Sat Feb 08, 2014 10:20 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: winter midterm 2009 #2
Replies: 1
Views: 369

winter midterm 2009 #2

during your camping weekend you use 2 moles of butane gas for cooking. the enthalpy of combustion is -2878 kj/mol. assume reaction occurs at 300 degrees celsius and constant pressure of 1atm. in the solutions they find the that moles goes from 15 to 18 and they get a change of moles is 3. where do t...
by 004253593
Fri Feb 07, 2014 3:30 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: cell potential
Replies: 4
Views: 1247

cell potential

what affects cell potentials?
adding water? adding mass? to cathode/anode
what else effects it and how?
by 004253593
Fri Feb 07, 2014 3:23 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 97
Replies: 1
Views: 363

97

do we have to know that AgOH forms an insoluble precipitate- what does that even mean?
by 004253593
Thu Feb 06, 2014 4:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 13.17
Replies: 3
Views: 1144

13.17

write balanced half reactions for the redox reactions of an acidified solution of potassium permanganate and iron II chloride. b. write balanced equation and cell diagram in the solutions they have the half equations for MnO4 and Fe3+, but there is no mention of potassium or chloride. what happened ...
by 004253593
Thu Feb 06, 2014 1:00 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: what equation?
Replies: 1
Views: 346

what equation?

show how change in S is related to change in H at constant temperature
by 004253593
Thu Feb 06, 2014 12:58 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: entropy
Replies: 1
Views: 400

entropy

Explain how temperature, volume and state of matter affect the entropy of a substance
by 004253593
Thu Feb 06, 2014 10:36 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: free energy
Replies: 2
Views: 531

free energy

why does reaction free energy depends on pressure and the equilibrium constant?
by 004253593
Wed Feb 05, 2014 5:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: anode and cathode
Replies: 4
Views: 638

Re: anode and cathode

also there is a t in cathode- so you could think of that as positive
by 004253593
Sun Feb 02, 2014 5:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: electrode
Replies: 1
Views: 311

electrode

when writing cell diagrams- which electrode should we use? I saw that you can use Pt(s) and C(s)- does it matter what one you use?
by 004253593
Sat Feb 01, 2014 6:33 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Work done by or on the system?
Replies: 2
Views: 571

Re: Work done by or on the system?

work done on the system is positive.it is usually a gas doing a work on the system. but work done by the system would be negative work.
by 004253593
Sat Feb 01, 2014 6:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt(s)
Replies: 1
Views: 2508

Pt(s)

what does the Pt(s) stand for in the cell diagrams. what is the difference if they are in the front or the back of the equations?

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