## Search found 34 matches

Sat Mar 16, 2019 10:05 pm
Forum: First Order Reactions
Topic: Half-Lives
Replies: 4
Views: 346

### Re: Half-Lives

If its on the formula, you most likely will need to know it/use it. Good luck!
Mon Mar 11, 2019 10:48 am
Forum: Student Social/Study Group
Topic: Note Taking
Replies: 32
Views: 2510

### Re: Note Taking

I would definitely take handwritten notes. It is so much easier because of all the math and graphs we have to write out/draw.
Mon Mar 04, 2019 10:34 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: "N" in Kinetics
Replies: 4
Views: 187

### "N" in Kinetics

What is "N"? What does order of the reactant mean?
Mon Mar 04, 2019 10:31 am
Forum: Balancing Redox Reactions
Topic: Test #2
Replies: 10
Views: 427

### Re: Test #2

Higher E value= more reducing power
Lower E value= more oxidizing power
Mon Mar 04, 2019 10:30 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Electrochemistry
Replies: 3
Views: 201

### Re: Electrochemistry

If the sign is changed, you add the two values. If not, you do cathode-anode. I was told to never reverse the sign and just stick to cathode-anode.
Mon Mar 04, 2019 10:29 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Integrals/derivatives
Replies: 3
Views: 162

### Integrals/derivatives

Are we expected to know how to solve integrals and derivatives?
Mon Mar 04, 2019 10:27 am
Forum: Balancing Redox Reactions
Topic: Cell diagrams
Replies: 8
Views: 266

### Re: Cell diagrams

Add P(t) solid to any side of the reaction that doesn't have a solid. So, if you only have gas, aqueous, or liquid on one side of the reaction, you need to add P(t). If there is a solid in one reaction and not the other, you still have to add Pt to the reaction without the solid.
Mon Mar 04, 2019 10:24 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 73
Views: 3840

### Re: Study Advice

Lyndon's Reviews are really helpful for me. It is also extremely beneficial to do all the homework problems and read through the textbook for clarification. Another thing that helps me is studying with friends. You can test each other and figure things out together!
Wed Feb 27, 2019 1:28 pm
Forum: Balancing Redox Reactions
Topic: basic/acidic solutions
Replies: 5
Views: 189

### Re: basic/acidic solutions

In all the examples he has given, it says basic or acidic solution. Remember that if it is acidic, then you add H+ and H2O (if needed). If it's basic, you add OH- and H2O (if needed).
Wed Feb 27, 2019 1:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt (s) [ENDORSED]
Replies: 8
Views: 349

### Pt (s)[ENDORSED]

Do we add Pt solid to reactions that contain a liquid as well, or only aqueous and gas?
Wed Feb 27, 2019 1:24 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: flipping the sign of Ecell
Replies: 5
Views: 217

### Re: flipping the sign of Ecell

You don't do anything to the sign of E if you decide to use (cathode-anode).
Fri Feb 22, 2019 9:47 pm
Forum: Balancing Redox Reactions
Topic: Redox Rxn
Replies: 3
Views: 153

### Redox Rxn

Can someone list the charges of different elements that we need to know in order to solve a redox? Like the halogens, group 1, etc.
Tue Feb 19, 2019 10:32 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: What to do when temperature isn't given
Replies: 8
Views: 228

### Re: What to do when temperature isn't given

For almost all the homework, they used 298 K (standard). I would assume that if you're not given a temp. and do not have enough info to solve for it, you would use 298 K.
Tue Feb 19, 2019 10:30 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous vs Not Spontaneous
Replies: 7
Views: 230

### Spontaneous vs Not Spontaneous

If the Gibbs Free Energy of the reaction is positive, does that always mean the reaction is not spontaneous? In other words, does it have to be negative to be spontaneous?
Tue Feb 19, 2019 10:29 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: O2
Replies: 5
Views: 190

### O2

Why is the Gibbs free energy of formation for O2 zero?
Mon Feb 04, 2019 2:10 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: W=2^NA
Replies: 3
Views: 157

### Re: W=2^NA

When you have 1 mole of a substance
Mon Feb 04, 2019 2:09 pm
Forum: Calculating Work of Expansion
Topic: Residual entropy
Replies: 1
Views: 98

### Re: Residual entropy

Use this when the system cools down and you are ignoring thermal entropy.

Ex: temperature= 0 Kelvin
Mon Feb 04, 2019 2:08 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Degeneracy
Replies: 5
Views: 209

### Re: Degeneracy

Degeneracy (W)= # of ways of achieving a given entry state.. *low energy

* W= 2^N
The more atoms or particles you have, the bigger the degeneracy.
Wed Jan 30, 2019 4:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Thermo Test/Midterm
Replies: 9
Views: 282

### Thermo Test/Midterm

Will we be given the lewis structures for bond enthalpies?
Wed Jan 30, 2019 4:28 pm
Forum: Calculating Work of Expansion
Topic: reversible & irreversible expansion
Replies: 2
Views: 97

### Re: reversible & irreversible expansion

The reversible expansion does the maximum amount of work because the gas is pushing against the maximum possible external pressure
Wed Jan 30, 2019 4:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 4
Views: 199

### Re: Hess's Law

I would start with one reactant, then product. Combine both those equations and cancel stuff out. Then do the third reactant and everything should cancel. Sometimes you have to do - deltaH to get a product/reactant one the correct side.
Mon Jan 28, 2019 9:07 pm
Forum: Ideal Gases
Topic: pH and pOH
Replies: 18
Views: 878

### Re: pH and pOH

pOH- base
pH-acid

then you can use the pOH+pH=14 to solve for the other one
Mon Jan 28, 2019 9:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cv and Cp
Replies: 3
Views: 136

### Re: Cv and Cp

Cp will always be slightly greater than Cv due to work being done.
Mon Jan 28, 2019 9:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Breaking Bonds
Replies: 4
Views: 164

### Breaking Bonds

How do you know exactly which bonds are broken/formed to avoid doing the longer calculation?
Mon Jan 21, 2019 12:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in ICE tables
Replies: 10
Views: 631

### Re: Water in ICE tables

Water is a pure substance and a solvent. The concentration won't change and it'll cancel out on both sides so theres no point in including it in an ice table or a Ka/Kb calculation.
Mon Jan 21, 2019 12:52 pm
Forum: Bronsted Acids & Bases
Topic: Sig Figs
Replies: 4
Views: 305

### Sig Figs

If we were to mess up on sig figs, do we get a lot of points taken off? I had a different chem professor for 14A and sig figs were insignificant.
Mon Jan 21, 2019 12:48 pm
Forum: Bronsted Acids & Bases
Topic: protonation and deprotonation
Replies: 2
Views: 321

### Re: protonation and deprotonation

In order to calculate the amount protonated or deprotonated, you do x/initial amount times 100.
Mon Jan 14, 2019 10:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homogeneous vs. Heterogenous [ENDORSED]
Replies: 1
Views: 67

### Re: Homogeneous vs. Heterogenous[ENDORSED]

Homogeneous equilibrium: the reactants and products are all in the same phase (example: all gases)
Heterogeneous equilibrium: one or more R or P is/are in a different phase
Mon Jan 14, 2019 10:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Forward vs. Reverse Reactions
Replies: 4
Views: 248

### Re: Forward vs. Reverse Reactions

If Q is less than K, there are more reactants then there should be at equilibrium so a forward reaction is favored (meaning we want to form more product. If Q is greater than K, there are more products than there should be so therefore a reverse reaction is favored (meaning we want to form more reac...
Mon Jan 14, 2019 10:13 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic Reaction
Replies: 3
Views: 92

### Exothermic Reaction

Why exactly does an exothermic reaction shifts towards the formation of products? What's the reasoning behind it?
Mon Jan 07, 2019 7:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentration vs Pressure
Replies: 6
Views: 184

### Re: Equilibrium Concentration vs Pressure

There was a problem that consisted of only gases but the concentration was used....
Mon Jan 07, 2019 6:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.7C
Replies: 2
Views: 117

### 11.7C

Can someone explain where the 2X came from? We weren't given a reaction or anything...
Mon Jan 07, 2019 6:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium vs Initial
Replies: 2
Views: 46

### Equilibrium vs Initial

Is equilibrium concentration or initial concentration used when solving for K?
Mon Jan 07, 2019 5:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentration vs Pressure
Replies: 6
Views: 184

### Equilibrium Concentration vs Pressure

Given a reaction, how do you know whether to write an equation for pressure or concentration? How do we know when to use Kc or Kp given just a reaction?

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