Search found 34 matches
- Sat Mar 16, 2019 10:05 pm
- Forum: First Order Reactions
- Topic: Half-Lives
- Replies: 4
- Views: 837
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: 145
- Views: 16456
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: 496
"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: 1119
Re: Test #2
Higher E value= more reducing power
Lower E value= more oxidizing 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: 449
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: 471
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: 816
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
- Topic: Study Advice
- Replies: 73
- Views: 7086
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: 568
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: 966
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: 693
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: 442
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: 887
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: 736
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: 523
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: 431
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: 250
Re: Residual entropy
Use this when the system cools down and you are ignoring thermal entropy.
Ex: temperature= 0 Kelvin
Ex: temperature= 0 Kelvin
- Mon Feb 04, 2019 2:08 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Degeneracy
- Replies: 5
- Views: 534
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.
* 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: 784
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: 276
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: 636
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: 1956
Re: pH and pOH
pOH- base
pH-acid
then you can use the pOH+pH=14 to solve for the other one
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: 330
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: 376
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: 2612
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: 505
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: 612
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: 133
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
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: 1660
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: 250
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: 443
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: 260
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: 107
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: 443
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?