Search found 11 matches

by Timothy_Yu_Dis3A
Sat Mar 18, 2017 3:02 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 4
Views: 929

Re: Ring Flip

In the diagram which ones are the original axiales and equatorial Im sorry I'm very confused on this topic. In the ring structure on the left, the blue hydrogen's are either axial up or down. The red hydrogen's are equatorial up or down. After the ring flip, the axial's become equatorial's with res...
by Timothy_Yu_Dis3A
Fri Mar 17, 2017 2:12 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 4
Views: 929

Re: Ring Flip

Yes, during a ring flip, the axial up's become equatorial up's and vice versa.

Consequently, axial down's will become equatorial down's and vice versa.

Here's a nice diagram of the ring flip of a cyclohexane in chair conformation that illustrates this.
by Timothy_Yu_Dis3A
Sat Mar 11, 2017 2:26 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: equilibrium constants and free energy [ENDORSED]
Replies: 1
Views: 850

Re: equilibrium constants and free energy [ENDORSED]

If the equilibrium constant = 0 and K = [Products]/[Reactants], then there are no products that form during the reaction. I don't think the equilibrium constant can ever reach 0 though because the Gibbs Free Energy is defined by G = -RTlnK, and ln(0) would be undefined. However, if the equilibrium c...
by Timothy_Yu_Dis3A
Sat Mar 04, 2017 4:07 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Chapter 4 Question 30
Replies: 1
Views: 426

Re: Chapter 4 Question 30

125 kJ/mol is a considered a high activation energy. Based on the Arrhenius equation, the rate will be very slow if the activation energy is high due to the large energy barrier it must overcome. If the activation energy is high, then the temperature must be high in order for the rate to be fast. Ro...
by Timothy_Yu_Dis3A
Sat Feb 25, 2017 6:57 pm
Forum: *Electrophiles
Topic: electrophiles turns into nucleophile [ENDORSED]
Replies: 1
Views: 308

Re: electrophiles turns into nucleophile [ENDORSED]

Yes? Water (H2O) can act as both an electrophile and a nucleophile. It depends on what it is binding with.
by Timothy_Yu_Dis3A
Sat Feb 18, 2017 3:13 pm
Forum: Zero Order Reactions
Topic: Zero Order and k [ENDORSED]
Replies: 2
Views: 529

Re: Zero Order and k [ENDORSED]

For [A] vs. Time and a zero order reaction, I think k is always equal to negative slope. We only get a positive k when we have a second order reaction for the plot of 1/[A] vs. Time.
by Timothy_Yu_Dis3A
Sat Feb 11, 2017 12:07 am
Forum: Calculating Work of Expansion
Topic: Which process does more work?
Replies: 5
Views: 657

Re: Which process does more work?

The work calculated for a reversible and isothermal pathway is the maximum work possible, therefore it is always a higher value as compared to the work calculated for an irreversible pathway. Real life processes are irreversible, as not all heat is converted to work.
by Timothy_Yu_Dis3A
Sat Feb 04, 2017 5:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: electrolytic solutions
Replies: 2
Views: 326

Re: electrolytic solutions

Hey! The conductivity of an electrolytic solution increases because a temperature increase would cause the ions inside the solution to have a higher kinetic energy and be more active. I'm not quite sure why the conductivity for a metal would decrease when the temperature is increased but when you de...
by Timothy_Yu_Dis3A
Sat Jan 28, 2017 2:19 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Assuming Constant Pressure?
Replies: 2
Views: 409

Assuming Constant Pressure?

For question 9.15, it asks you to calculate the entropy change for the freezing of 1.00 mol of H2O(l) at 0.00 degrees C. I get how to solve this by Delta S = Delta H/T but I understand that the only way Delta H = q is if there is constant pressure. This isn't explicitly mentioned in the problem so i...
by Timothy_Yu_Dis3A
Sun Jan 22, 2017 12:38 am
Forum: Calculating Work of Expansion
Topic: Irreversible vs. Reversible Expansion (Question 8.11) [ENDORSED]
Replies: 1
Views: 297

Irreversible vs. Reversible Expansion (Question 8.11) [ENDORSED]

I understand how to solve question 11 for Chapter 8 by using the formulas for calculating the work for the irreversible and reversible expansion respectively. However, I recall Dr. Lavelle mentioning (though I'm not 100% sure) during lecture that reversible expansion always does more work. If this i...
by Timothy_Yu_Dis3A
Sat Jan 14, 2017 4:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Chapter 8 #59 [ENDORSED]
Replies: 3
Views: 506

Re: Chapter 8 #59 [ENDORSED]

To elaborate, N2(g) -> N2(g) contains no broken or new bonds being formed. Therefore, the enthalpy is 0. The same can be seen in Oxygen gas (O2(g) -> O2(g)).

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