## Search found 30 matches

Sat Mar 17, 2018 1:34 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 3
Views: 406

### Re: Arrhenius Equation

Why do you use k2/k1?
Sat Mar 17, 2018 1:28 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Lyndon Review Test, Question 7a [ENDORSED]
Replies: 7
Views: 519

### Re: Lyndon Review Test, Question 7a[ENDORSED]

Where can I find Lyndon's review test?
Sat Mar 17, 2018 1:27 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Negative activation energy?
Replies: 2
Views: 209

### Re: Negative activation energy?

Where can I find this practice final?
Sat Mar 17, 2018 1:26 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energy
Replies: 5
Views: 448

### Re: Activation Energy

Since the reaction has multiple steps, there will be multiple transition states, which means multiple energy barriers.
Sat Mar 17, 2018 1:24 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst
Replies: 4
Views: 414

### Re: catalyst

Catalysts provide an alternate pathway for the reactants which requires less energy than without them.
Sat Mar 17, 2018 1:19 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Transition State
Replies: 3
Views: 377

### Re: Transition State

The transition state is the area between reactants and products where there is an energy barrier(activation energy) the must be met to complete the reaction. It is always the peak of the energy profile because all reactions have an energy barrier.
Sun Mar 11, 2018 9:25 pm
Forum: Zero Order Reactions
Topic: Definition of Reaction Rate
Replies: 4
Views: 434

### Re: Definition of Reaction Rate

It's given in units of M because we're studying the change in concentration, but there are questions using rate equations in the homework that involve mass of a given substance.
Sun Mar 11, 2018 9:18 pm
Forum: Zero Order Reactions
Topic: Half-Life of Zero Order
Replies: 3
Views: 383

### Re: Half-Life of Zero Order

Since Dr. Lavelle covered the derivation in class, you should assume it's fair game for the final just in case. It's on the equation sheet so you should be fine as long as you know what it is.
Sun Mar 11, 2018 9:15 pm
Forum: First Order Reactions
Topic: Pseudo First Order Reaction
Replies: 7
Views: 1020

### Re: Pseudo First Order Reaction

Expanding on this, what is a pseudo first order reaction?
Sun Mar 04, 2018 10:08 pm
Forum: General Rate Laws
Topic: Rate equations
Replies: 3
Views: 288

### Re: Rate equations

He hasn't asked for derivations on any of our tests so far, but knowing the derivation may help with applying the equation or answering conceptual questions.
Sun Mar 04, 2018 10:05 pm
Forum: General Rate Laws
Topic: Instantaneous Rate
Replies: 3
Views: 278

### Re: Instantaneous Rate

The instantaneous rate is the rate at one point one the reaction. More specifically, we use the instantaneous rate at time=0 so that no products have been formed and we can define the rate only with the concentration of the reactants.
Sun Mar 04, 2018 10:02 pm
Forum: General Rate Laws
Topic: a value
Replies: 3
Views: 269

### Re: a value

Are you talking about a as in - $\frac{1}{a}\frac{d[A]}{dt}$ ? That a would be the molar coefficient of reactant A.
Sun Feb 25, 2018 10:01 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Pressure in calculating Q
Replies: 4
Views: 271

### Re: Pressure in calculating Q

If you remember from 14A as long as we are studying something in a gaseous state we can use partial pressure or concentration to calculate Q since the pressure of gas will also affect the reaction direction.
Sun Feb 25, 2018 9:54 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation to find pH
Replies: 6
Views: 2992

### Re: Nernst Equation to find pH

Using the Nernst equation you can find the concentration of H+ ions which you can use to find pH. There was a homework problem that gave you pH and asked to find E, try looking at the solution for that if you're still confused.
Sun Feb 25, 2018 9:50 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: anode vs cathode in non standard cell diagram
Replies: 5
Views: 389

### Re: anode vs cathode in non standard cell diagram

The anode is usually on the left but if you're not sure you can just check which has the higher Eo value
Sun Feb 11, 2018 11:50 pm
Forum: Van't Hoff Equation
Topic: Derivation
Replies: 9
Views: 652

### Re: Derivation

It's unlikely the derivations will appear on a test since we're given the equations, but as the above users have said it would be helpful to know them since understanding them would help you know how to apply them.
Sun Feb 11, 2018 11:36 pm
Forum: Van't Hoff Equation
Topic: Finding K
Replies: 5
Views: 721

### Re: Finding K

Dr. Lavelle has mentioned in lecture that we won't need to to ICE tables
Sun Feb 11, 2018 11:35 pm
Forum: Van't Hoff Equation
Topic: Reaction Coefficient, Q
Replies: 2
Views: 327

### Re: Reaction Coefficient, Q

The lowercase letters a, b, c, and d all refer to the molar coefficients of each part of the reaction, and the upper case letters A, B, C, and D refer to the components of the reaction, with C and D as products and A and B as reactants.
Sun Feb 04, 2018 2:56 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Residual Entropy
Replies: 4
Views: 324

### Re: Residual Entropy

Is residual entropy related to how there is a standard entropy of formation for gas molecules like O2 that are already in their standard state?
Sun Feb 04, 2018 2:53 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Perfect Crystal
Replies: 9
Views: 611

### Re: Perfect Crystal

Can someone explain why entropy of a "perfect crystal" is 0 (S=0)? At 0K there is no movement of atoms so there is only one possible state for each molecule in a crystal, so it is perfectly ordered and we can know the exact position of everything. Since there is only one possible state, d...
Sun Feb 04, 2018 2:45 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Third Law
Replies: 3
Views: 282

### Re: Third Law

Because there is no movement at 0K, there is only one possible state (so w=1), which makes entropy equal to 0.
Sun Jan 28, 2018 10:55 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: About entropy and gibbs free energy
Replies: 2
Views: 195

### Re: About entropy and gibbs free energy

To piggyback on the post above, the total ∆G of the two reactions combined must still be negative, so the spontaneous reaction must release more free energy than the non-spontaneous reaction uses.
Sun Jan 28, 2018 10:25 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Boltzmann Equation Clarification
Replies: 3
Views: 172

### Re: Boltzmann Equation Clarification

Can someone explain how it depends on temperature? Since T isn't part of the equation, are there different values of Kb depending on the temperature?
Sun Jan 28, 2018 10:15 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Positional disorder?
Replies: 2
Views: 155

### Re: Positional disorder?

Potential disorder is another way of saying the amount of potential different states of a system, so it is the same as degeneracy. This shouldn't be important though since Dr. Lavelle wants to avoid using the term disorder altogether.
Fri Jan 19, 2018 12:00 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 5
Views: 1785

### Re: Specific Heat Capacity

I think Dr. Lavelle said in lecture on Wednesday that the solution is so dilute that that salt(in the case of acid-base reactions) has very little impact on the specific heat capacity and you can just use the capacity of the solvent.
Thu Jan 18, 2018 11:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar heat capacity
Replies: 3
Views: 196

### Re: Molar heat capacity

Using the ideal gas equation, $n=\frac{PV}{RT}$, so the number of moles of a certain gas can change as pressure or volume change.
Thu Jan 18, 2018 11:47 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: State function in relation to heat
Replies: 3
Views: 261

### Re: State function in relation to heat

Adding to the other posts, when we calculate the change in internal energy of a system, ∆U = Q + W, Q represents the energy that the system either loses or gains as heat, not the heat the system possesses.
Thu Jan 11, 2018 3:23 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of sublimation
Replies: 3
Views: 305

### Re: Enthalpy of sublimation

Another way to think about this is to remember that enthalpy is a state function, so the path taken doesn't matter. Since sublimation is changing directly from a solid to a vapor, the beginning and end points are the same as a a substance that goes through fusion and then vaporization, so the ∆H of ...
Thu Jan 11, 2018 3:20 pm
Forum: Phase Changes & Related Calculations
Topic: Ideal Gas
Replies: 5
Views: 305

### Re: Ideal Gas

If something behaves like an ideal gas, it means it follows the ideal gas law PV=nRT.
Mon Jan 08, 2018 6:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Having the textbook in discussion
Replies: 2
Views: 210

### Having the textbook in discussion

Do we need to bring a physical copy of the textbook to discussion sections, or can we use a pdf on our laptops?

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