Search found 47 matches

Sat Mar 17, 2018 11:13 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Final
Replies: 3
Views: 294

Re: Final

I think that's pretty much what we should know since there wasn't much covered in lecture about it other than that
Sat Mar 17, 2018 11:10 pm
Forum: Balancing Redox Reactions
Topic: Acidic/ basic conditions
Replies: 4
Views: 405

Re: Acidic/ basic conditions

yeah I think the only difference is adding OH- to balance the H+. Then the OH- and H+ ions on the same side can be added to form H2O
Sat Mar 17, 2018 11:03 pm
Forum: *Electrophiles
Topic: what is going to be on the final? [ENDORSED]
Replies: 12
Views: 1290

Re: what is going to be on the final?[ENDORSED]

Joyce Gu 1E wrote:where can i find this practice final?

search red panda and you'll find it!
Sat Mar 17, 2018 10:46 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Replies: 5
Views: 1861

adiabatic means there is no heat transfer and isothermal means that the temperature stays constant
Sat Mar 10, 2018 10:46 pm
Forum: First Order Reactions
Topic: Integrated Rate Laws
Replies: 4
Views: 394

Re: Integrated Rate Laws

with 1st order reactions there is only one reactant but for 2nd order reactions there can be two first order reactants but I think most of the time we will use reactions with one 2nd order reactant because that uses the 2nd order integrated rate law found on the formula sheet of the test
Sat Mar 10, 2018 10:36 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant? [ENDORSED]
Replies: 5
Views: 442

Re: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant?[ENDORSED]

for part a) since catalysts speed up the rate of a reaction the rate law would be affected in that the value of the rate would be larger than the rate of the reaction without the presence of a catalyst. for part b) the lowered activation energy means that the constant is greatly increased, which is ...
Sat Mar 10, 2018 10:12 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Collision theory and transition state theory?
Replies: 2
Views: 127

Re: Collision theory and transition state theory?

the collision theory says that gas molecules only react if they collide with enough kinetic energy, and the transition state theory says that the reactants form an activated complex, which is also known as a transition state
Sat Mar 10, 2018 9:58 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: types of systems
Replies: 3
Views: 453

Re: types of systems

a pot without a lid on a stove is an example of a common open system, while a pot with a lid is an example of a closed system. an isolated system could be something like a thermos
Sat Mar 10, 2018 9:55 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Heterogenous vs homogenous
Replies: 2
Views: 208

Re: Heterogenous vs homogenous

I'm not sure if this answers your question, but one advantage of using heterogenous catalysts is that you can easily recover the catalyst for reuse whereas homogenous catalysts mix with the reaction so you can't really recover it
Sat Mar 10, 2018 9:43 pm
Forum: Second Order Reactions
Topic: the slope
Replies: 12
Views: 824

Re: the slope

In regards to the graphs, how do you know what the y intercepts are?
Sat Feb 24, 2018 11:29 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: n
Replies: 8
Views: 446

Re: n

Keliana Hui 2E wrote:What does order of reactants mean?

The order of the reactant is the value of n, which is the exponent of the concentration of the reactant in the rate law
Sat Feb 24, 2018 10:59 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: negative order
Replies: 2
Views: 173

Re: negative order

The book also states that increasing the concentration of a species with a negative order would slow down the reaction because it participates in a reverse reaction
Sat Feb 24, 2018 10:52 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order
Replies: 5
Views: 325

Re: Order

What would an order that's a fraction mean?
Sat Feb 17, 2018 11:17 pm
Forum: Balancing Redox Reactions
Topic: Basic vs Acidic Conditions
Replies: 2
Views: 404

Re: Basic vs Acidic Conditions

I think the only difference is having to add OH- to each side to balance the H+. Then the OH- and H+ on one side of the reaction can be added to form water and then cancel out the common terms on each side
Sat Feb 17, 2018 10:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 3
Views: 210

Cell Diagram

how does one go about writing out a cell diagram?
Sat Feb 17, 2018 9:34 pm
Forum: Balancing Redox Reactions
Topic: Test #2
Replies: 5
Views: 334

Re: Test #2

Yep it's just electrochemistry. The class website says it'll cover chapter 14.1-14.11
Sat Feb 10, 2018 11:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Concept of Second Law of Thermodynamics
Replies: 6
Views: 532

Re: Concept of Second Law of Thermodynamics

The second law of thermodynamics states that in an isolated system, entropy is always increasing and the system degenerates into a more disordered state
Sat Feb 10, 2018 11:00 pm
Forum: Calculating Work of Expansion
Topic: Degeneracy [ENDORSED]
Replies: 2
Views: 219

Re: Degeneracy[ENDORSED]

Degeneracy is the number of ways of chivying a given energy state, and degeneracy's relation to entropy is found in the Boltzmann equation of S=kblnW, in which the number of microstates, or degeneracy, is W
Sat Feb 10, 2018 10:58 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 2
Views: 219

Re: Bond Enthalpies

to convert to the gas phase you use the enthalpy of sublimation or vaporization and take those values into account when calculating the total enthalpy
Sat Feb 03, 2018 11:18 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: entropy vs. Degeneracy
Replies: 4
Views: 323

Re: entropy vs. Degeneracy

also, degeneracy is taken into account when computing the actual value of entropy. their relationship between each other is seen in the Boltzmann equation
Sat Feb 03, 2018 11:08 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Isothermal pressure change
Replies: 3
Views: 161

Re: Isothermal pressure change

I think the reason P1/P2 is used is because it is inversely proportional to volume, which uses V2/V1. Also since both pressure and volume are directly proportional to temperature, does it matter which one uses 1/2 or 2/1?
Sat Feb 03, 2018 11:04 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Degeneracy vs Disorder
Replies: 4
Views: 306

Re: Degeneracy vs Disorder

Also, degeneracy is the value W in the Boltzmann equation, which is S=KblnW
Sat Jan 27, 2018 11:09 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: Third Law of Thermodynamics
Replies: 4
Views: 266

Re: Third Law of Thermodynamics

in class it was said that the third law of thermodynamics says that the limit of S as the temperature approaches 0 Kelvin equals 0. What that says is that the entropy at 0 Kelvin is 0, so it is perfectly ordered material
Sat Jan 27, 2018 10:56 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: Perfect Crystal
Replies: 9
Views: 559

Re: Perfect Crystal

In friday's lecture, Dr. Lavelle's powerpoint said "if a system can be prepared in only one way, then S=KblnW=0". What did he mean by prepared in only one way? I'm not completely sure what he meant by this line and how it relates to the equation. When it says something can only be prepare...
Sat Jan 27, 2018 10:49 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Maximum Entropy
Replies: 1
Views: 61

Maximum Entropy

Why is entropy at its maximum at equilibrium?
Sat Jan 20, 2018 11:10 pm
Forum: Phase Changes & Related Calculations
Topic: Test 1 topics
Replies: 2
Views: 248

Re: Test 1 topics

I don't know if any specific homework problems will be covered on the test, so I think it's more important to understand concepts and equations that we covered in class, such as enthalpy and work, and be able to apply them to whatever questions are asked
Sat Jan 20, 2018 10:57 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Perfect Isolated System
Replies: 3
Views: 210

Re: Perfect Isolated System

While the argument can be made that the universe can technically be considered a perfectly isolated system, fully isolated systems that are confined to our world are rare
Sat Jan 20, 2018 10:10 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Open Beaker [ENDORSED]
Replies: 5
Views: 693

Re: Open Beaker[ENDORSED]

Yes because it can equilibriate with the pressure of the surroundings
Sat Jan 13, 2018 11:57 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy and Internal Energy
Replies: 2
Views: 153

Re: Enthalpy and Internal Energy

Internal energy is the energy stored in the system as kinetic and potential energy. Enthalpy is calculated with the internal energy, which is the energy required to make the system, along with the energy required to make room for the system, the product of the pressure and volume.
Sat Jan 13, 2018 11:45 pm
Forum: Phase Changes & Related Calculations
Topic: Steam Burning
Replies: 7
Views: 500

Re: Steam Burning

Steam burns a lot more than boiling water because more energy is required for phase changes than just temperature changes. With boiling water, the energy that is transferred to the skin will come from the temperature change, but with the steam, a lot of energy will be released onto the skin from the...
Sat Jan 13, 2018 11:28 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Constant pressure vs. Constant volume
Replies: 1
Views: 184

Re: Constant pressure vs. Constant volume

In constant volume the system doesn't expand, so the heat added will only go towards increasing temperature. However, expansion can occur at constant pressure, and some of the heat added will be spent on that expansion, along with increasing temperature. Since some of the heat will be spent in expan...
Sat Dec 09, 2017 3:31 pm
Forum: Biological Examples
Topic: Biological Importance of Coordination Compounds [ENDORSED]
Replies: 2
Views: 470

Biological Importance of Coordination Compounds[ENDORSED]

Which coordination compounds are the most prominent in regards to their biological importance? Which should we be able to identify and understand?
Sat Dec 09, 2017 2:57 pm
Forum: Properties of Light
Topic: Speed of light wavelength equation [ENDORSED]
Replies: 4
Views: 400

Re: Speed of light wavelength equation[ENDORSED]

since the value of c is constant, being the speed of light, you can use the equation to solve for either wavelength of frequency, depending on what the given values are
Sat Dec 02, 2017 11:54 pm
Forum: Bronsted Acids & Bases
Topic: Lewis Acids and Bases Vs. Bronsted Acids and Bases
Replies: 4
Views: 351

Re: Lewis Acids and Bases Vs. Bronsted Acids and Bases

will we be asked to identify which molecule is a bronsted acid/base or Lewis acid/base like in your example above on the final?
Sat Dec 02, 2017 11:48 pm
Forum: Amphoteric Compounds
Topic: Amphoteric and Amphiprotic
Replies: 1
Views: 200

Amphoteric and Amphiprotic

Are we expected to know examples of them or is it sufficient enough to understand what they are/what they can do?
Sat Nov 25, 2017 11:11 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 5
Views: 611

Re: Sigma and Pi Bonds

idk if this helps but it shows how there can be more than just one pi bond. it also shows how a sigma bond forms in comparison to pi bonds
Sat Nov 25, 2017 11:00 pm
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 2
Views: 179

Re: Naming Coordination Compounds

Iron is used when the compound is positively charged, and ferrate is used when the compound is negatively charged.
Sat Nov 18, 2017 10:50 pm
Forum: Hybridization
Topic: Difference between sigma and pi bonds?
Replies: 6
Views: 1329

Re: Difference between sigma and pi bonds?

I know you can have multiple pi bonds, but can you have multiple sigma bonds? In all of our examples it seems that there is only ever one sigma bond. You can have multiple sigma bonds if you're counting bonds in a molecule, say for example a molecule has a single bond and a double bond, then there ...
Sat Nov 18, 2017 10:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 3
Views: 262

Re: Bond angles

And while you know that the angles will be either slightly larger or slightly smaller, I think the only way to find out the exact angle is to look it up
Sat Nov 11, 2017 9:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance
Replies: 3
Views: 268

Re: Resonance

Since all bonds are treated as equivalent in the VSEPR model, it doesn't matter which resonance structure is used
Sat Nov 11, 2017 5:35 pm
Forum: Trends in The Periodic Table
Topic: Isoelectronic [ENDORSED]
Replies: 4
Views: 386

Re: Isoelectronic[ENDORSED]

Since it needs to have the same nuimber of valence electrons, something isoelectronic with F- would have 10 valence electrons and have the same electron configuration of Ne, such as Na+ or O2-
Sat Oct 28, 2017 5:12 pm
Forum: Resonance Structures
Topic: How to find the most stable structure [ENDORSED]
Replies: 3
Views: 456

Re: How to find the most stable structure[ENDORSED]

so does that mean in order to find the most stable structure it's kind of a trial and error type thing? like you just keep changing the structure around and calculating the formal charge until you find it?
Sat Oct 28, 2017 5:10 pm
Forum: Octet Exceptions
Topic: Octet Rule Exception
Replies: 1
Views: 169

Octet Rule Exception

What is it that allows elements to be excepted from the octet rule? How do we know how many more electrons the element can carry?
Sat Oct 21, 2017 7:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d and 4s
Replies: 3
Views: 230

Re: 3d and 4s

^ this is because potassium and calcium don't have electrons that occupy the 3d orbital, whereas elements after do.
Sat Oct 21, 2017 7:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electric Spin
Replies: 5
Views: 308

Re: Electric Spin

Does that mean that when doing configurations it doesn't matter if we choose clockwise or counterclockwise spin for single electrons? Or is there a preference?
Sat Oct 14, 2017 6:23 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.13 [ENDORSED]
Replies: 1
Views: 153

Question 1.13[ENDORSED]

a) Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n=4 to n=2. I understand the calculation of the change in energy, but in calculating the wavelength using the equation lambda= ch/E, why do we discard the negative?
Sat Oct 14, 2017 6:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy