Search found 20 matches

by dchenny206
Mon Mar 13, 2017 2:16 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Confusion about Z and E naming
Replies: 1
Views: 296

Confusion about Z and E naming

On page 103 in the course reader, there are examples of alkenes being named, but I'm not entirely sure how the priority of two different groups are determined. Can someone explain this to me? Without understanding how the priority is determined, it is impossible to name the molecule. Thanks.
by dchenny206
Mon Mar 06, 2017 12:45 am
Forum: *Organic Reaction Mechanisms in General
Topic: SN2 Reactions
Replies: 2
Views: 281

SN2 Reactions

Are SN2 reactions always for biomolecular molecules? When drawing the curved arrow diagrams, is it possible to show more than 1 bond breaking (the relocation of two pairs of electrons instead of just one?
by dchenny206
Mon Mar 06, 2017 12:39 am
Forum: *Organic Reaction Mechanisms in General
Topic: Diagram on Page 85
Replies: 1
Views: 201

Diagram on Page 85

On Page 85, there is a graph that displays the progress of an reaction with respect to the free energy that the reaction has. On the graph, it says that step 1 is slower because of the higher energy barrier, but I don't quite understand why there is a higher energy barrier at the beginning. Is this ...
by dchenny206
Mon Feb 20, 2017 11:52 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 1
Views: 285

Arrhenius Equation

I'm very confused about what the graphs on page 75 in the course reader represent. Arrhenius's Equation: k = A e^ (-E(a)/RT) >>> Produces a exponential curve. Simplification of the Arrhenius's Equation: ln k = -Ea/RT + ln A >>> Produces a linear slope. I'm not entirely sure what the graphs of these ...
by dchenny206
Sun Feb 12, 2017 10:18 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Confusion about intermediates
Replies: 4
Views: 386

Confusion about intermediates

On page 69 of the course reader, a proposed reaction mechanism is outlined in two steps: STEP 1: NO2(g) + NO2(g) --> NO3(g) + NO(g) STEP 2: NO3(g) + CO(g) --> NO2(g) + CO2(g) ______________________________________ OVERALL RXN: NO2(g) + CO(g) --> NO(g) + CO2(g) Before that, it says that the proposed ...
by dchenny206
Sun Feb 05, 2017 9:04 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Sensitivity of Cell Potential
Replies: 1
Views: 182

Sensitivity of Cell Potential

On page 53 of the course reader, it is claimed that the cell potential is sensitive to [R] and [P] (concentration of reactants and products. Discussed earlier in the quarter, the course reader refined an extensive property as something that depends on the number of substance. For example, heat capac...
by dchenny206
Sun Jan 29, 2017 5:29 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Confusion about K and Q and Equilibrium
Replies: 1
Views: 266

Confusion about K and Q and Equilibrium

From page 40 to 41 in the course reader, it seems like there are 2 equations for ΔG, one where K is used and another where Q is used: (1) ΔG = -RT ln (K) where K is the reaction quotient at equilibrium (ΔG = 0 and G(p) = G(r)) AND (2) ΔG = ΔG° + RT ln (Q) where Q is the reaction quotient when the sy...
by dchenny206
Sat Jan 21, 2017 8:19 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Application of Degeneracy [ENDORSED]
Replies: 1
Views: 256

Application of Degeneracy [ENDORSED]

On page 28, the course reader says that degeneracy (W) is defined as the number of ways of achieving a given energy state. The relationship between degeneracy (W) and entropy (S) is given by the Boltzmann Equation: S = k(b) ln(W). On page 31, there is another equation given by the change in entropy ...
by dchenny206
Sun Jan 15, 2017 5:32 pm
Forum: Phase Changes & Related Calculations
Topic: ΔH = ΔU Page 20 Confusion
Replies: 1
Views: 218

ΔH = ΔU Page 20 Confusion

On Page 20 in the Course Reader, an example is worked out where the concept is demonstrating that Q(system) = -Q(surroundings) and that Q(system) + Q(surrounding) = 0. I understand how the conclusion was deduced that ΔH(rxn) = -2.9 kJ at the end (because there was constant pressure, indicating that ...
by dchenny206
Fri Mar 11, 2016 10:11 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Newman Projections for Cyclohexanes
Replies: 1
Views: 315

Newman Projections for Cyclohexanes

How do we draw the Newman Projection for cyclohexane?
by dchenny206
Fri Mar 11, 2016 10:10 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Stable Conformation of Cyclopentane & Cyclohexane
Replies: 1
Views: 431

Stable Conformation of Cyclopentane & Cyclohexane

Can someone explain the envelope conformation of cyclopentane? Is there only one conformation?

Also for cyclohexanes, can someone explain why the equatorial and axial positions are switched?
by dchenny206
Fri Feb 26, 2016 9:36 pm
Forum: *Alkanes
Topic: Organic Chemistry Emergency
Replies: 1
Views: 268

Organic Chemistry Emergency

Hey fellow Chemistry peers. Please help me distinguish between tert-butyl and neopentane.

Thanks!
by dchenny206
Tue Feb 23, 2016 10:45 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Section 4.3 HW number 4.30
Replies: 1
Views: 225

Section 4.3 HW number 4.30

If one has the activation energy, how do we determine whether it will occur at a specific temperature. I know we have to use:

delta(g) = delta(h) - (time)*(delta(s))

What do I need to solve it?
by dchenny206
Tue Feb 16, 2016 11:41 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Equations for finding the Activation Energy
Replies: 1
Views: 284

Equations for finding the Activation Energy

When do we use each equation to find the activation energy? When would you chose one over the other?

k=A ^ -Ea/R*T
ln(k) = -Ea/R*T + ln(A)
by dchenny206
Tue Feb 16, 2016 11:29 pm
Forum: General Rate Laws
Topic: Units for K
Replies: 1
Views: 328

Units for K

Hi. Can anyone explain the difference between the units for k for a first order reaction, a second order one and a zero order one? I know they're different because the change of the rate needs to be in Molarity/Second.
by dchenny206
Fri Feb 05, 2016 5:38 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Platinum and Salt Bridges
Replies: 1
Views: 425

Platinum and Salt Bridges

In my discussion section, my TA told me that platinum was a strong reducing metal. Can anyone tell me why this is the case. Also what is the common makeup for a salt bridge?
by dchenny206
Sat Jan 30, 2016 1:47 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Dissolving a Gold Ring in 1M Nitric Acid
Replies: 1
Views: 421

Dissolving a Gold Ring in 1M Nitric Acid

On page 52 of the course reader, a question asks whether a gold ring would dissolve in 1M nitric acid and whether it would form a 1M Aluminum 3 Oxide solution. I understand the process of calculating the E and Delta G, but I don't understand how it is deduced that gold does not dissolve in 1M of nit...
by dchenny206
Fri Jan 22, 2016 5:01 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Degrees of Freedom
Replies: 1
Views: 293

Degrees of Freedom

What is the difference between transitional and rotational degrees of freedom? Also, how do you calculate it? Is there any connection between degrees of freedom and the Gibbs Free Energy equation?
by dchenny206
Fri Jan 15, 2016 4:21 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Clairifcation on when to use entropy equations.
Replies: 3
Views: 571

Clairifcation on when to use entropy equations.

In class today,

I wrote down the following two equations:

Change in entropy = Boltzmann's Constant * ln (w2/w1)

and

Change in entropy = number of moles * Ideal Gas Constant * ln (w2/w1)

When would each equation be used and how can these two equations possibly be used to calculate the same thing?
by dchenny206
Fri Jan 08, 2016 7:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Course Reader Page 19 and 20
Replies: 1
Views: 207

Course Reader Page 19 and 20

I understand that one can calculate standard reaction enthalpy by calculating standard enthalpy of formation of all products and subtract standard enthalpy of formation of all reactants. I am also aware that the standard enthalpy of formation of an element in its most stable form is zero. On page 20...

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