## Search found 30 matches

Mon Mar 11, 2019 2:54 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Frequency factor A
Replies: 7
Views: 321

### Re: Frequency factor A

In the book it says "A is a measure of the rate at which molecules collide" and this rate refers to the frequency of molecules colliding.
Mon Mar 11, 2019 2:43 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre equilibrium approach
Replies: 3
Views: 193

### Re: Pre equilibrium approach

Adding onto this, the slow step is the rate determining step.
Mon Mar 11, 2019 2:40 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: "Bottle Neck"
Replies: 2
Views: 147

### "Bottle Neck"

Lavelle mentioned mentioned this term when talking about intermediates, can someone please explain what he meant?
Wed Mar 06, 2019 4:23 pm
Forum: Second Order Reactions
Topic: graph for second order
Replies: 7
Views: 336

### Re: graph for second order

The reaction rate for a second order graph has a positive slope because k (the slope) is positive.
Sun Mar 03, 2019 4:27 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Electrolysis
Replies: 4
Views: 219

### Re: Electrolysis

Yes, electrolysis takes place in an electrolytic cell where electrical energy is converted into chemical energy.
Sun Mar 03, 2019 2:31 am
Forum: General Rate Laws
Topic: Unique vs instantaneous rate
Replies: 6
Views: 243

### Re: Unique vs instantaneous rate

The unique rate only applies to a given reaction such as a A ---> b B + c C because it has coefficients, unlike instantaneous rate.
Sun Mar 03, 2019 2:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Question 14.83 (Sixth Edition)
Replies: 1
Views: 102

### Re: Question 14.83 (Sixth Edition)

Looking at the equation sheet for Ecell and E⁰cell will help find relationships and to start off question a, E⁰cell does not decrease with time whereas Ecell does.
Wed Feb 27, 2019 4:28 pm
Forum: Balancing Redox Reactions
Topic: 14.5 6th edition
Replies: 2
Views: 131

### Re: 14.5 6th edition

In the beginning of the question it mentioned that the reactions are taking place in a basic solution and to balance redox rxns in a basic solution you add OH- and H2O to balance it instead of H+.
Wed Feb 27, 2019 4:13 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Thermodynamic Stability
Replies: 2
Views: 306

### Thermodynamic Stability

If a compound is thermodynamically stable does that mean it is also spontaneous?
Wed Feb 27, 2019 3:45 pm
Forum: Balancing Redox Reactions
Topic: basic/acidic solutions
Replies: 5
Views: 207

### Re: basic/acidic solutions

The question will tell you if the redox reaction is in an acidic or basic solution.
Wed Feb 20, 2019 3:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode v. Cathode
Replies: 9
Views: 356

### Anode v. Cathode

Why must anodes be on the left and cathodes on the right?
Wed Feb 20, 2019 3:19 pm
Forum: Administrative Questions and Class Announcements
Topic: midterm
Replies: 2
Views: 164

### Re: midterm

After lecture from your TA's today 2/20.
Wed Feb 20, 2019 3:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Positive vs Negative E value
Replies: 5
Views: 2972

### Re: Positive vs Negative E value

Ecell = Cathode(right)-Anode(left) and this is found from the half oxidation and reduction equations.
Wed Feb 20, 2019 3:12 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous vs Not Spontaneous
Replies: 7
Views: 258

### Re: Spontaneous vs Not Spontaneous

A spontaneous reaction must release free energy so delta G must be negative to be spontaneous.
Wed Feb 20, 2019 3:09 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy and mass
Replies: 2
Views: 311

### Entropy and mass

What is the relationship between entropy and the mass of an atom?
Wed Feb 13, 2019 1:28 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: state function
Replies: 4
Views: 159

### Re: state function

State functions could be thought of in the pneumonic that Lyndon told us
PD TV HUGS (Pressure, Temperature, Velocity, H (enthalpy), U (internal energy), G (gibbs free energy), S (entropy) are all state functions:
"under Pressure, feeling Depressed, just wanna watch TV and get HUGS"
Wed Feb 13, 2019 1:21 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: Finding W (degeneracy)
Replies: 4
Views: 393

### Re: Finding W (degeneracy)

W = # of possible energy states ^ # of molecules
Wed Feb 06, 2019 5:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work and Internal Energy
Replies: 1
Views: 88

### Re: Work and Internal Energy

Since work=w=-PΔV, when V is constant, there is no change in V or ΔV=0 and w=-P(0)=0. So ΔU=q.
Sat Feb 02, 2019 5:40 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: The Relationship Between ΔH and ΔU
Replies: 2
Views: 147

### The Relationship Between ΔH and ΔU

Why is ΔU referred to heat transfer at constant volume and ΔH for constant pressure? How are they related?
Sat Feb 02, 2019 4:03 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reversible rxn
Replies: 5
Views: 164

### Re: Reversible rxn

A reversible process is one that can be reversed by an "infinitesimal" change in a variable.
Sat Feb 02, 2019 3:58 pm
Forum: Calculating Work of Expansion
Topic: work done by vs on a system
Replies: 5
Views: 250

### Re: work done by vs on a system

This is correct. If work is done BY a system, energy is being released making it exothermic resulting in w being negative. If work is done ON a system, w is positive, because it is endothermic and energy is being put into the system.
Fri Jan 25, 2019 9:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: An element's standard state
Replies: 2
Views: 94

### Re: An element's standard state

You know that something is in its standard state if it satisfies certain conditions: 1. The temperature should be 25 degrees Celsius (usually). 2. All liquids and solids are pure. 3. The concentration of all solutions is 1 M at 1 atm. 4. All gases are at 1 atm. 5. Elements are in their most stable p...
Fri Jan 25, 2019 8:59 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating Q
Replies: 11
Views: 886

### Re: Calculating Q

You calculate the reaction quotient (Q) when you are determining which direction the reaction shifts. Q=[Products]/[Reactants] just as K. If Q<K then the reaction shifts right to form towards products and if Q>K then the reaction shifts left to form towards the reactants.
Mon Jan 21, 2019 1:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for equilibrium constants
Replies: 2
Views: 129

### Re: Units for equilibrium constants

Because K is a ratio of units, they are cancelled out in the equilibrium expression making it unitless.
Thu Jan 17, 2019 5:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: How to tell if a chemical is an acid or base?
Replies: 4
Views: 271

### Re: How to tell if a chemical is an acid or base?

There is also a list of strong acids and bases. Here is a quizlet link of the top 6 strong acids and bases!

https://quizlet.com/41246443/6-strong-a ... ash-cards/
Wed Jan 16, 2019 1:44 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 7
Views: 151

### Re: Le Chatelier's Principle

Le Chatelier's Principle adjusts to minimize the effect of changes. For example, when more reactant is added, more product will form until the original product to reactant ratio is attained.
Wed Jan 16, 2019 1:18 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Pka and Acidty
Replies: 2
Views: 325

### Pka and Acidty

If Ka<10^-3, then it's a weak acid. So does this mean that the larger the pKa, the weaker the acid?
Fri Jan 11, 2019 2:28 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic Reactions
Replies: 9
Views: 383

### Re: Exothermic Reactions

Also, if a reaction is exothermic while forming products, then heating will favor reaction formations.
Fri Jan 11, 2019 2:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q 11.47
Replies: 3
Views: 180

### Re: Q 11.47

First you'd have to make an ICE table.
Fri Jan 11, 2019 2:10 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in pressure
Replies: 2
Views: 103

### Re: Change in pressure

For the initial concentration, K= 100. When pressure doubled, Q=25. When Q<K, the reaction shifts to the right.