## Search found 31 matches

- Sun Mar 18, 2018 8:51 am
- Forum: Second Order Reactions
- Topic: Derivations
- Replies:
**4** - Views:
**650**

### Derivations

When deriving the integrated law for a second order reaction why isn't the kt negative, and also does a positive kt value mean that the slope of the line of 1 over the concentration of reactant plotted against time will be positive as well?

- Sat Mar 17, 2018 11:13 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pseudo Rate Laws
- Replies:
**5** - Views:
**716**

### Pseudo Rate Laws

Can someone please explain Pseudo Rate Laws and how they are obtained. Thank you

- Sat Mar 17, 2018 5:39 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Second Law application
- Replies:
**3** - Views:
**397**

### Second Law application

According to the second law of thermodynamics the natural progression of a system along with its surroundings is from lower entropy to higher entropy, so wouldn't that mean that a reaction with a positive change in entropy be a spontaneous one? But when we implement Gibbs free energy we see that und...

- Sat Mar 17, 2018 2:59 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre-Equilibrium
- Replies:
**2** - Views:
**221**

### Pre-Equilibrium

When using the pre-equilibrium method when we get our final rate law and we have an equilibrium constant K in it, is it more correct to express that K as the forward rate constant over the reverse or just leave it as is?

- Sun Mar 11, 2018 10:03 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: SN2
- Replies:
**2** - Views:
**174**

### SN2

Can someone please explain what a nucleophile is and how exactly do they replace certain atoms within a molecule to produce a completely new molecule?

- Sun Mar 11, 2018 9:59 pm
- Forum: *Enzyme Kinetics
- Topic: 15.81
- Replies:
**1** - Views:
**237**

### 15.81

Can someone please show me how to approach problem 15.81 from the book. How are we suppose to account for the loss of the unreacted substrate from the active site?

- Sun Mar 11, 2018 9:55 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy and heat
- Replies:
**2** - Views:
**192**

### Internal Energy and heat

When the temperature of a system doesn't change does the heat equal 0? Or is that just the change in the internal energy of the system?

- Sun Mar 04, 2018 5:39 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Homework Problem 15.45
- Replies:
**1** - Views:
**145**

### Homework Problem 15.45

To write the overall reaction for the mechanism that is proposed in the given problem all we need to do is add the reactions together? Also how can we tell which step is the longest one?

- Sun Mar 04, 2018 5:32 pm
- Forum: Second Order Reactions
- Topic: Half life constant and Rate reaction constant
- Replies:
**4** - Views:
**325**

### Half life constant and Rate reaction constant

When we find the constant K for a reaction from the half life equation can we apply that same constant to the second order reaction equation to find the concentration of a given reactant?

- Sun Mar 04, 2018 5:31 pm
- Forum: Zero Order Reactions
- Topic: Significance of Zero order reactions
- Replies:
**3** - Views:
**253**

### Significance of Zero order reactions

Can someone please explain the significance of zero order reactions as they relate to the rates of reactions and give an example of one? Thank you

- Sun Feb 25, 2018 8:20 pm
- Forum: General Rate Laws
- Topic: Rate Constants
- Replies:
**4** - Views:
**325**

### Rate Constants

Why do the rate constants of each molecule being composed or consumed correspond with a different temperature, why aren't they all under standard conditions of 298K?

- Sun Feb 25, 2018 8:15 pm
- Forum: First Order Reactions
- Topic: Reaction Order [ENDORSED]
- Replies:
**6** - Views:
**541**

### Reaction Order [ENDORSED]

So do the reaction orders of reactions depend upon the amount of moles decomposed in a standard decomposition reaction?

- Sun Feb 18, 2018 10:03 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies:
**5** - Views:
**372**

### Concentration Cells

What are the significance of concentration cells?

- Sun Feb 18, 2018 9:11 pm
- Forum: Balancing Redox Reactions
- Topic: Basic and Acidic conditions [ENDORSED]
- Replies:
**11** - Views:
**3671**

### Basic and Acidic conditions [ENDORSED]

So under basic conditions there is water that is balanced out on both sides by water itself and hydroxide? And under acidic solutions there are hydrogen molecules balanced out by water molecules?

- Sun Feb 18, 2018 9:06 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: The Nernst Equation
- Replies:
**2** - Views:
**370**

### The Nernst Equation

Can someone please derive the Nernst equation the way we did it in class one more time? Thank you

- Sun Feb 11, 2018 10:08 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.55, 9.57
- Replies:
**1** - Views:
**122**

### 9.55, 9.57

Can someone please explain why in problem 9.55 we only use the delta H of formation of the products to find the Standard change in enthalpy of the reaction, but in 9.57 we subtract the the sum of the enthalpy of the formation of products by the sum of the enthalpy of formation of reactants. Don't we...

- Sun Feb 11, 2018 3:35 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Using q reversible
- Replies:
**1** - Views:
**150**

### Using q reversible

When calculating the change in entropy why do we need to take into account the heat transfer, q, of a reversible reaction instead of an irreversible reaction. Is this due to the fact that the work done by a reversible reaction is greater than the work done in an irreversible one therefore through th...

- Sun Feb 11, 2018 3:34 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: ∆S = n R ln (V2/V1 )
- Replies:
**1** - Views:
**564**

### ∆S = n R ln (V2/V1 )

I don't have the derivation of this equation in my notes, so if we derived this one in class can someone please show me how we do it again. Thank you so much. ∆S = n R ln (V2/V1 )

- Sun Feb 04, 2018 9:23 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Homework Problem 9.69
- Replies:
**1** - Views:
**131**

### Homework Problem 9.69

I'm not sure how to approach this problem and the significance of the pH=7 for Gibbs Free Energy. If anyone can help me understand it I really appreciate it thank you.

- Sun Feb 04, 2018 9:19 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Max work related to Gibbs Free Energy
- Replies:
**2** - Views:
**167**

### Re: Max work related to Gibbs Free Energy

Thank you so much

- Sun Feb 04, 2018 5:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Max work related to Gibbs Free Energy
- Replies:
**2** - Views:
**167**

### Max work related to Gibbs Free Energy

Does the change in Gibbs Free Energy always represent the maximum work or is it when the Pressures and Temperatures are constant in a spontaneous reaction?

- Sun Feb 04, 2018 2:14 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Using Q
- Replies:
**2** - Views:
**197**

### Using Q

Can we use Q when calculating Gibbs free energy with the Equation deltaG= -RTlnQ? Or does the reaction need to be at equilibrium for us to use this equation, in which case we would use K.

- Sun Jan 28, 2018 1:24 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: Spontaneous Processes for Entropy
- Replies:
**2** - Views:
**259**

### Spontaneous Processes for Entropy

So in all cases when the change in entropy is positive the process is spontaneous? Or is it specifically when we use the equation when we take Delta S=nRln(V1/V2) because V2 is greater than V1?

- Sun Jan 28, 2018 1:15 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy Change of Phase Changes
- Replies:
**1** - Views:
**622**

### Entropy Change of Phase Changes

When calculating the entropy change of a specific phase change do we use the enthalpy change? Also for example in #9.15 when calculating the change in entropy of a liquid becoming a solid do we take the negative value of the enthalpy change of fusion in this case?

- Sun Jan 28, 2018 11:58 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Homework Problem 9.13
- Replies:
**1** - Views:
**89**

### Homework Problem 9.13

When given a problem like this one when a gas changes both volume and temperature how would we calculate the entropy change? Do we take each change individually, for example do we take the change from 3L to 0.500L first into account and calculate the entropy change and then the change of temperature...

- Sun Jan 21, 2018 6:06 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Homework Problem 8.99
- Replies:
**1** - Views:
**126**

### Homework Problem 8.99

Can someone please explain the solution to this problem. I understand that we find the standard reaction enthalpies and through that we calculate the enthalpy of the overall reaction, but from then on I'm a little confused as to how we find the heat released of the system.

- Sun Jan 21, 2018 4:01 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Homework Problem 8.41
- Replies:
**2** - Views:
**147**

### Homework Problem 8.41

So when given a problem of this type, when a colder solid substance such as ice is submerged into a warmer surrounding of water, when calculating the heat given off by the system which is the ice in this case, we always assume the ice will melt? Meaning that we should always take into account the en...

- Sun Jan 21, 2018 3:54 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Standard Enthalpies of Formation
- Replies:
**3** - Views:
**220**

### Standard Enthalpies of Formation

So when calculating the total enthalpy of a reaction and we are given standard enthalpies of formation of the individual products and reactants all we need to do from there is add up the bonds formed in the products and the bonds broken in the reactants and subtract the total enthalpy of the formed ...

- Mon Jan 15, 2018 12:05 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Homework Problem 8.31
- Replies:
**2** - Views:
**157**

### Homework Problem 8.31

When finding the heat capacity at constant volumes and constant pressures when do you know to multiply R by 3/2, 5/2,7/2, 3, or 4? Does it only have to do with whether the sample is an atom, linear molecule or nonlinear molecule?

- Sun Jan 14, 2018 1:27 pm
- Forum: Calculating Work of Expansion
- Topic: Homework Problem 8.9
- Replies:
**2** - Views:
**279**

### Re: Homework Problem 8.9

You would first calculate the work being done by the system by using the equation -Pex*Delta V. After making the proper conversions and finding the work being done by the system, you then subtract the work done on the system which is 5.50 kJ by the work done by the system.

- Sun Jan 14, 2018 1:08 pm
- Forum: Calculating Work of Expansion
- Topic: Homework Problem 8.3 Using Proper Units
- Replies:
**1** - Views:
**164**

### Homework Problem 8.3 Using Proper Units

For problem 8.3 when finding the change in the volume of the bicycle pump in order to find the work, the solutions manual found it in liters, but in the book it states that when finding work we should only work in Pascals for pressure and meters cubed for volume. It makes the conversion for Pascals ...