Search found 10 matches

by Matt Goff 1F
Sat Mar 18, 2017 11:56 pm
Forum: *Alkenes
Topic: Cis and Trans
Replies: 2
Views: 397

Re: Cis and Trans

How do we use E and Z in cycloalkenes with multiple double bonds? What's the quickest way to determine priority?
by Matt Goff 1F
Tue Feb 21, 2017 10:31 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: pre equilibrium approach (question about something in the coursereader)
Replies: 1
Views: 257

Re: pre equilibrium approach (question about something in the coursereader)

We are trying to see if the reaction mechanism proposed accurately leads us to the given observed rate of k[NO]^2[O2]. 1/2d[NO2]/dt comes from looking at the balanced reaction on the first line of this page and writing out the rate in terms of the formation of NO2. You do that the same way it's done...
by Matt Goff 1F
Wed Feb 15, 2017 1:59 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 2015 Midterm Q4&5 part D
Replies: 3
Views: 300

Re: 2015 Midterm Q4&5 part D

Water vapor will not necessarily turn to liquid water when brought back down to room temp, which is the tricky part of this question. If you look at a phase diagram for water you can see that at a low enough pressure, water can be in the vapor phase in the whole range of temps for this question. Log...
by Matt Goff 1F
Tue Feb 14, 2017 6:42 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Winter 2013 Midterm #7: Which Nernst Equation to Use?
Replies: 2
Views: 252

Re: Winter 2013 Midterm #7: Which Nernst Equation to Use?

I just did it your way and got K = 9.2 x 10^-72, which is the same as when I used \Delta G=-RTlnK , which is just a different way to do it. It says at the bottom of the page though they accepted 9.2 x 10^-72 as well as 1.0 x 10^-71 for the answer for K, so you should be good as long as you put the n...
by Matt Goff 1F
Tue Feb 14, 2017 6:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Midterm 2012 #7
Replies: 4
Views: 319

Re: Midterm 2013 #7

I think they meant the 2013 Winter midterm question 7. The original equation is: Mn^2^+ (aq) + Br_2(l) \rightarrow MnO_4^-(aq) + Br^-(aq) And the half rxns are: MnO_4(aq) + 8H^+ + 5e^- \rightarrow Mn^2^+ (aq) + 4H_2O(l) , E^0=+1.49V Br_2(l&...
by Matt Goff 1F
Sat Feb 11, 2017 1:52 pm
Forum: Phase Changes & Related Calculations
Topic: Open, Closed, and Isolated Systems
Replies: 8
Views: 564

Re: Open, Closed, and Isolated Systems

A constant pressure calorimeter gives enthalpy values (as the definition of enthalpy is heat at constant pressure). A constant volume calorimeter is a bomb calorimeter. You can remember this because as the volume stays constant and a reaction (igniting oxygen) takes place, the pressure increases ins...
by Matt Goff 1F
Sun Jan 29, 2017 11:33 pm
Forum: Phase Changes & Related Calculations
Topic: Significance of State Functions
Replies: 1
Views: 198

Re: Significance of State Functions

"Is it because these functions are state functions that we can use the final and initial for the change of them (delta)?"

Yes. For something like work, which is not a state function, the path does matter so a less meaningful value is obtained from the final-initial calculation.
by Matt Goff 1F
Sun Jan 22, 2017 9:32 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy and phase changes
Replies: 1
Views: 261

Re: Entropy and phase changes

I believe this is because the entropy of vaporization is a ratio (between the enthalpy of vaporization and the boiling temperature). You can find a lot on it if you look up Trouton's rule. Hope this helps!
by Matt Goff 1F
Thu Jan 12, 2017 6:29 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 2
Views: 197

Re: Phase Changes

Temperature is defined as the average kinetic energy, and this does not change as ice melts, for example. However, breaking the bonds in ice (H-bonds) requires heat to be added. I think the part confusing you is looking at the flat part as constituting more "time," when really it's just a ...

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