## Search found 38 matches

Sat Mar 17, 2018 5:31 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 1
Views: 200

That would mean that the rate would quadruple or multiply by 6.

If you increase your reactant for a second order, that means that the rate would be increased by the square of however much you increased your reactant.
Sat Mar 17, 2018 5:26 pm
Forum: *Nucleophiles
Topic: Electrostatic Attraction
Replies: 1
Views: 425

### Re: Electrostatic Attraction

Electrostatic Attraction has to do with nucleophilic substitution.

It is when a nucleophile attracts an electrophile to the point where a part of the molecule leaves thus, substituting it.
Sat Mar 17, 2018 5:23 pm
Forum: Zero Order Reactions
Topic: Shortcut
Replies: 1
Views: 175

### Re: Shortcut

If it is 0th order, then it would just be M/s.
For 1st order, it would just be 1/s.
For 2nd order, it would just be M^-1/s.

So, the shortcut is to subtract the exponent of M (1) by the order that the reaction is.
Sat Mar 17, 2018 5:19 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Practice Final 2010
Replies: 1
Views: 234

### Re: Practice Final 2010

To use Cp or Cv, you would have to have constant pressure or constant volume, respectively.
Thu Mar 08, 2018 5:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-Equilibrium Approach Methodology
Replies: 2
Views: 137

### Pre-Equilibrium Approach Methodology

Why do we set the rate law equal to the formation of product in the pre-equilibrium approach?
Mon Mar 05, 2018 9:39 pm
Forum: Second Order Reactions
Topic: 2nd order rxn integration
Replies: 2
Views: 127

### 2nd order rxn integration

In the integration for the 2nd order rxn, where does the negative go?
Sun Mar 04, 2018 9:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Friday Lecture
Replies: 5
Views: 211

### Friday Lecture

I understand the concept of intermediate species. I just do not get how just from the NO2 eqn and the rate eqn, we got that an intermediate species is needed. In the lecture notes, Lavelle states that "NO2 cannot form NO and CO2 so there must be an intermediate species" but in the eqn itse...
Sun Mar 04, 2018 11:54 am
Forum: Second Order Reactions
Topic: 15.35 homework
Replies: 2
Views: 139

### Re: 15.35 homework

Also, I used a ratio instead of the actual values given and I got the wrong answer? Why is that?
Sun Mar 04, 2018 11:50 am
Forum: Second Order Reactions
Topic: 15.35 homework
Replies: 2
Views: 139

### 15.35 homework

Why can't we use the same trick that was used in 27 to determine the half-lives for the times that are multiples of 2?
Sun Mar 04, 2018 11:07 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 0 order
Replies: 6
Views: 2119

### Re: 0 order

If you look at page 631 in the chemistry textbook it shows you in the table.

However, the graph itself has an x-axis of time and a y-axis of the concentration of A at time t with a slope that is equal to -k and a y-intercept of the initial concentration of A.
Sun Mar 04, 2018 11:04 am
Forum: First Order Reactions
Topic: 15.23
Replies: 4
Views: 188

### Re: 15.23

It is because that accounts for the change in reactants going to products. Since, products is produce that means the reactants must be reduced. So, you would subtract the 0.068 from the initial reactant concentration.
Sat Feb 24, 2018 5:29 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.41b. Homework b
Replies: 2
Views: 174

### 14.41b. Homework b

In the solutions manual, it says that the n=1. However when I separate the rxn into two half-rxn, the n=2?
Sat Feb 24, 2018 4:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Q of eqn [ENDORSED]
Replies: 2
Views: 147

### Q of eqn[ENDORSED]

Why can you include concentration and partial pressure when calculating the Q of a rxn?
Mon Feb 19, 2018 4:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13
Replies: 5
Views: 333

### Re: 14.13

In the problem I am referring to, there is an equation given where it can go either way. So it is not as easy as looking at which species is oxidized or reduced( or which species is losing or gaining electrons). What I have figured out is that the anode usually has the lower E of cell? Is that a goo...
Mon Feb 19, 2018 3:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13
Replies: 5
Views: 333

### 14.13

How do you tell which equation is the anode and which is the cathode ?
Sun Feb 18, 2018 6:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Notation
Replies: 1
Views: 114

### Cell Notation

When do you add Pt(s) to the cell notation? Also, how do you recognize the species that you would put in that place rather than the Pt(s) in the equation?
Sun Feb 18, 2018 4:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Potential
Replies: 1
Views: 101

### Cell Potential

What does the book mean when it takes about "pushing and pulling" regarding to the potential difference?

When it states that a rxn with a lot of pushing and pulling power generates high potential difference or a high voltage.
Mon Feb 12, 2018 7:00 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Calorimetry
Replies: 2
Views: 142

### Calorimetry

In a calorimetry problem where ice with a temperature below 0 C is put into water and you are asked to find the final temperature, would you have to have 3 q's for ice: one for the change of heat for ice to 0, the H of fusion and then the change of heat from 0 to the final temperature? or would you ...
Sun Feb 11, 2018 11:26 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework Problem 9.69
Replies: 2
Views: 132

### Homework Problem 9.69

I don't understand how the second and third equations relate to the first one. How does that help us find the answer?
Sun Feb 11, 2018 11:24 pm
Forum: Phase Changes & Related Calculations
Topic: Lyndons practice midterm
Replies: 3
Views: 249

### Re: Lyndons practice midterm

As Lyndon said in the review, water can evaporate in a room that is room temperature without having to reach boiling point. If you think of the temperature change graphs, a phase change is one where the temperature does not have to change. Thus, the temperature does not have to change for there to b...
Sun Feb 11, 2018 10:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework Problem 9.65
Replies: 2
Views: 123

### Homework Problem 9.65

How do we tell if something will become more or less stable as T increases? Don't we not have enough information to tell that?
Mon Feb 05, 2018 11:28 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Homework Problem 9.17
Replies: 1
Views: 136

### Homework Problem 9.17

Why do we have to account for the entropy of the cooling process when finding the standard entropy of vaporization of water?
Sun Feb 04, 2018 11:58 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy in real life
Replies: 1
Views: 122

### Re: Entropy in real life

The entropy of a room may decrease with the cooling of the system. However, that does not mean that the whole system would have the entropy decrease. The heat particles just flow to a different object. DeltaS means the change in total entropy as the energy of contents of the two components change so...
Sun Feb 04, 2018 11:47 pm
Forum: Calculating Work of Expansion
Topic: Midterm [ENDORSED]
Replies: 3
Views: 188

### Midterm[ENDORSED]

For the midterm, we will not need to know any of the equations (just the connections between the variations), right? Or will not all of them be on the eqn sheet?
Sun Feb 04, 2018 11:44 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: maximum G
Replies: 3
Views: 164

### Re: maximum G

"Energy is free to do all useful work" so the Gmax is just when the work stops being useful with the process.
Sun Feb 04, 2018 11:42 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: maximum G
Replies: 3
Views: 164

### Re: maximum G

If you think about it on the graph that Dr. Lavelle showed us, there is a minimum to the parabolic curve meaning that the free energy of process cannot go below it. The process itself is at equilibrium so, it cannot spontaneously change and if work is put into it it will only be able to go up on the...
Sun Feb 04, 2018 11:38 pm
Forum: Calculating Work of Expansion
Topic: Lecture notes, free energy graph
Replies: 1
Views: 73

### Re: Lecture notes, free energy graph

Nevermind I just answered this for myself.

On the graph, a process that leads towards equilibrium is spontaneous while one that leads away equilibrium is non-spontaneous.
Sun Feb 04, 2018 11:34 pm
Forum: Calculating Work of Expansion
Topic: Lecture notes, free energy graph
Replies: 1
Views: 73

### Lecture notes, free energy graph

During lecture, there was a graph presented showing spontaneous processes as going down a parabolic curve. Does that non-spontaneous processes happen at equilibrium?
Mon Jan 29, 2018 8:00 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Clausius Inequality
Replies: 1
Views: 212

### Clausius Inequality

I was reading the textbook and I am a bit confused on the Clausius Inequality and the logic of getting to it. I understand in what context we would use this equation in but not the concept itself.
Mon Jan 22, 2018 10:05 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Lecture notes, Boltzmann Eqn [ENDORSED]
Replies: 1
Views: 77

### Lecture notes, Boltzmann Eqn[ENDORSED]

After the introduction of Boltzmann Equation, there were some notes about error in the thermodynamic property and in the statistical. I do not really understand this concept of small and large "error"
Mon Jan 22, 2018 7:59 pm
Forum: Calculating Work of Expansion
Topic: 8.117 Homework Problem
Replies: 1
Views: 86

### 8.117 Homework Problem

Why is the net production of gas 2/3?
Sun Jan 21, 2018 3:58 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.67
Replies: 3
Views: 175

### 8.67

For a. when calculating bond enthalpies one finds the enthalpy of formation for water in its gas state. However, the equation has water in its liquid state. So, how do we know that water is in its gas state versus knowing it is in its liquid state?
Sun Jan 21, 2018 2:47 pm
Forum: Calculating Work of Expansion
Topic: Lecture notes , work eqn
Replies: 3
Views: 154

### Re: Lecture notes , work eqn

So, the system being at equilibrium means that it is a reversible process?
Sun Jan 21, 2018 12:21 am
Forum: Calculating Work of Expansion
Topic: Lecture notes , work eqn
Replies: 3
Views: 154

### Lecture notes , work eqn

This is from the lecture notes on Friday. Do we only use the work equation when the system is at equilibrium? Because that is when we use the derivative for the small changes in V that leads to the integral of the work eqn.
Mon Jan 15, 2018 5:47 pm
Forum: Calculating Work of Expansion
Topic: 8.13
Replies: 2
Views: 81

### 8.13

For this problem, why is the heat added (947 kJ) negative? I thought when you add heat to a system it is supposed to be positive?
Sun Jan 14, 2018 3:40 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Irreversible vs. Reversible [ENDORSED]
Replies: 10
Views: 498

### Irreversible vs. Reversible[ENDORSED]

I read about this in the textbook and I understand that you are supposed to use two different equations for each but what is the difference between these two processes?
Sun Jan 14, 2018 2:46 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Systems
Replies: 3
Views: 219

### Re: Systems

An open system is one that can exchange matter and energy with its surroundings. A closed system is one that can only exchange energy and an isolated is one that can't exchange either matter or energy.
Sat Jan 13, 2018 3:36 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Work vs. Heat
Replies: 6
Views: 321

### Work vs. Heat

Is this difference between work and heat the same difference between velocity and speed? Why I think of this is because in the textbook it describes the fundamental difference between these two is that when energy is transferred as work, the molecules in the surroundings move in directed directions ...