Search found 50 matches

by Emily Burghart 1k
Sat Mar 14, 2020 8:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 275
Views: 131350

Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, Although I know that my comment will be lost alongside many, I would like to say thank you. I switched majors over the summer from political science to a stem major and my first quarter was extremely rough; I didn't know how I was going to survive 14 B. Although I still struggled (and d...
by Emily Burghart 1k
Sat Mar 14, 2020 8:22 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: elementary rate law
Replies: 4
Views: 53

Re: elementary rate law

What was most helpful in understanding the mechanism functionality of an overall rate law?
by Emily Burghart 1k
Sat Mar 14, 2020 8:16 pm
Forum: Administrative Questions and Class Announcements
Topic: ENDGAME Review Session
Replies: 71
Views: 2547

Re: ENDGAME Review Session

You're great! thank you for posting a comprehensive answer key despite not being able to have the review session!!

Your sessions were very helpful!
by Emily Burghart 1k
Sat Mar 14, 2020 8:13 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: order of reaction
Replies: 6
Views: 69

Re: order of reaction

This is a good video! I watched another of his videos on other general kinetics problems, and it was good. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=15&cad=rja&uact=8&ved=2ahUKEwiOp82665voAhXMi54KHRqgAZsQtwIwDnoECAkQAQ&url=https%3A%2F%2Fwww.you...
by Emily Burghart 1k
Sat Mar 14, 2020 8:10 pm
Forum: Second Order Reactions
Topic: Graphs
Replies: 7
Views: 85

Re: Graphs

This is a good chart for reference.
by Emily Burghart 1k
Sat Mar 14, 2020 8:07 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Endgame 15b
Replies: 5
Views: 71

Re: Endgame 15b

TanveerDhaliwal3G wrote:I think the k' is supposed to signify the combination of the first rate constant and the concentration of A


How did you get that from the problem? Is there a simple way of figuring that out?
by Emily Burghart 1k
Sat Mar 14, 2020 12:37 pm
Forum: General Rate Laws
Topic: Study Resources for Kinetics
Replies: 1
Views: 23

Study Resources for Kinetics

Does anyone have a good video/ website that helped them understand kinetics better?

I have been studying kinetics a lot, but seem to need some additional review!
by Emily Burghart 1k
Wed Mar 11, 2020 12:09 pm
Forum: First Order Reactions
Topic: determining Kr
Replies: 5
Views: 37

Re: determining Kr

JasonLiu_2J wrote:Also to add on, remember that for a first order reaction, the slope of the graph ln[A] vs time is -k, so you would need to multiply it by negative 1 to find the value of the rate constant.


Why are we able to just multiply the slope by -1 to find the rate constant?
by Emily Burghart 1k
Mon Mar 09, 2020 6:39 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1357364

Re: Post All Chemistry Jokes Here

Chem jokes
by Emily Burghart 1k
Sun Mar 01, 2020 10:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 2
Views: 39

Re: Nernst Equation

the Nernst Equation relates cell potential with concentrations: E = E^naught - (RT/nF)*lnQ E^naught is the cell potential at standard conditions. R = Gas constant T = Temp in Kelvin N = mols of e- F = Faraday's constant Q = Reaction Quotient Another way of explaining n, is by saying it is the numbe...
by Emily Burghart 1k
Sun Mar 01, 2020 10:16 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Metal dissolution
Replies: 10
Views: 305

Re: Metal dissolution

Is there a way of knowing if the metal will be oxidized? Do certain metals oxidize easier than others? Which metals are least likely to oxidize and dissolve into solution? Refer to the ordered electrochemical series. Metals with half-reactions that appear later in the table (more negative E^0) are ...
by Emily Burghart 1k
Sun Mar 01, 2020 10:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 35

Re: Cell Diagrams

205007651 wrote:The only order that matters is anode on the left and cathode on the right, and having aqueous next to salt bridge.


Why does it matter to have aqueous next to the salt bridge?
by Emily Burghart 1k
Sun Mar 01, 2020 10:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to determine anode and cathode in 6.57?
Replies: 6
Views: 51

Re: How to determine anode and cathode in 6.57?

Natalie Benitez 1E wrote:The cathode should be the one with the larger E value.


Why again is the cathode the one with the larger E value?
by Emily Burghart 1k
Sun Mar 01, 2020 10:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagrams
Replies: 7
Views: 43

Re: Writing cell diagrams

When writing cell diagrams from a given reaction when do we separate species with a comma? is this due to the species being in the same phase? If this is true would you also separate products and reactants in the same phase with a comma as well? In addition to this, you separate the sides of the re...
by Emily Burghart 1k
Sun Mar 01, 2020 10:01 pm
Forum: Balancing Redox Reactions
Topic: OH and H
Replies: 8
Views: 68

Re: OH and H

In a test style problem, would the question say something alongs the lines of "In the acidic rxn..." or must we be able to identify that? Otherwise, if we were to accidentally use OH- when we were supposed to use H+, would a significant number of points be taken off?
by Emily Burghart 1k
Sun Feb 23, 2020 10:44 pm
Forum: Student Social/Study Group
Topic: Sapling Learning
Replies: 4
Views: 85

Re: Sapling Learning

When I took chem 14A with Caram, for the most part the Sapling was not that helpful. I do believe Lavelle has some problems he's pulled from there for test/exam questions. However, doing all the textbook problems is your better bet, along with going to step up sessions/ workshops.
by Emily Burghart 1k
Sun Feb 23, 2020 10:35 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: test 2 material clarification
Replies: 10
Views: 110

Re: test 2 material clarification

Test 2 will cover the information on the 2nd page of the Thermodynamics and the electrochemistry outline.
by Emily Burghart 1k
Sun Feb 23, 2020 10:31 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity
Replies: 8
Views: 72

Re: Spontaneity

Yes, due to their inverse relationship in the equation -nFEcell, when the cell potential of the battery is positive, the
becomes negative
by Emily Burghart 1k
Sun Feb 23, 2020 10:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell diagrams
Replies: 5
Views: 45

Re: cell diagrams

Is it important to have a detailed cell diagram for your answer/work in your problems, or is supposed to function as more of a basis for your equation?
by Emily Burghart 1k
Tue Feb 18, 2020 10:14 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1357364

Re: Post All Chemistry Jokes Here

Found on Pinterest
by Emily Burghart 1k
Tue Feb 18, 2020 10:12 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1357364

Re: Post All Chemistry Jokes Here

Ahh you Noble Gasses
by Emily Burghart 1k
Tue Feb 18, 2020 10:01 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 16
Views: 517

Re: Activation Energy

The activation energy of a reaction is the peak of an energy diagram. Beginning where the products are located to the height of the peak is how much energy is needed to cause the reaction to happen. Some reactions have very low activation energies, and others have high activation energies. It is imp...
by Emily Burghart 1k
Tue Feb 18, 2020 9:56 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: intermediate
Replies: 22
Views: 587

Re: intermediate

If an intermediate is formed during a reaction, and then used, do non-state functions include those changes and quantities?
by Emily Burghart 1k
Tue Feb 18, 2020 9:53 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Study Advice
Replies: 73
Views: 3653

Re: Study Advice

I end up doing the readings from the book and I make sure to do the example problems as I go along to make sure I have grasp the subject. The practice problems are helpful and the evening step up sessions are helpful if you need extra guidance on certain problems.
by Emily Burghart 1k
Tue Feb 18, 2020 9:49 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Temperature Dependence
Replies: 4
Views: 31

Re: Van't Hoff Temperature Dependence

What equation do you use if you are not sure if the equation has a equal to 0?

Is there a way to check that is 0 if it is not explicitly stated in the problem?

What happens if you use the equation for a reaction that is not at equilibrium?
by Emily Burghart 1k
Tue Feb 18, 2020 9:38 pm
Forum: Environment, Fossil Fuels, Alternative Fuels
Topic: Why ethanol?
Replies: 4
Views: 848

Re: Why ethanol?

Ethanol is a byproduct of the fermentation of plants, which makes it readily available. We will always have a fuel source if we are producing plants. Although they still contribute to global warming, our society cannot immediately switch to fuel sources powered by solar, nuclear or wind/water becaus...
by Emily Burghart 1k
Mon Feb 17, 2020 3:44 pm
Forum: Balancing Redox Reactions
Topic: Reduction vs. oxidation
Replies: 29
Views: 212

Re: Reduction vs. oxidation

Reduction and oxidation is how an electron is transferred. The notation taught in LS is OIL RIG. Oxidation is Loss of electrons Reduction is Gain of electrons When something becomes oxidized, the oxidation number becomes more positive. Being reduced means your oxidation number becomes more negative.
by Emily Burghart 1k
Mon Feb 17, 2020 3:34 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Metal dissolution
Replies: 10
Views: 305

Re: Metal dissolution

Is there a way of knowing if the metal will be oxidized? Do certain metals oxidize easier than others? Which metals are least likely to oxidize and dissolve into solution?
by Emily Burghart 1k
Mon Feb 17, 2020 3:21 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Number Rules
Replies: 7
Views: 66

Re: Oxidation Number Rules

Are there any oxidation numbers of specific compounds that would be helpful to know?
by Emily Burghart 1k
Sun Feb 02, 2020 10:02 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work done BY vs work done ON
Replies: 9
Views: 77

Re: Work done BY vs work done ON

When work is done by a system, the system is affecting the surroundings. ex. exothermic rxn, -


When work is done on a system, the surroundings are affecting the system. ex. endothermic rxn,
by Emily Burghart 1k
Sun Feb 02, 2020 9:55 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Negative Enthalpy
Replies: 3
Views: 27

Re: Negative Enthalpy

Are you asking about spontaneous reactions?
by Emily Burghart 1k
Sun Feb 02, 2020 8:58 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: degeneracy
Replies: 3
Views: 45

Re: degeneracy

What can we learn from the degeneracy of a system? when x=2 n=3 W=8, but what does that mean? Is it anything more than knowing that degeneracy is the number of ways of achieving a given state?
by Emily Burghart 1k
Sun Feb 02, 2020 8:52 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: microstates
Replies: 3
Views: 38

Re: microstates

Because the different micro states all have the same energies, is there any instance we would have to use a micro state in an equation and specify the one we are using?
by Emily Burghart 1k
Sun Feb 02, 2020 8:40 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Affect of temperature on entropy?
Replies: 5
Views: 55

Re: Affect of temperature on entropy?

Yes, as temperature increases, entropy increases due to the excited nature of the molecules within a system.
by Emily Burghart 1k
Sun Feb 02, 2020 8:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of Rxn
Replies: 9
Views: 75

Re: Enthalpy of Rxn





As you can see here, you will want to multiply the values to cancel out the mol, so you are left with kJ. You are left with 15kJ.
by Emily Burghart 1k
Sun Feb 02, 2020 8:12 pm
Forum: Phase Changes & Related Calculations
Topic: Relevance of Phase Changes
Replies: 9
Views: 67

Re: Relevance of Phase Changes

In many of the problems covered in thermo, you have to calculate the energies expelled/absorbed for each part of the phase change, and then add those up to find your enthalpy, .
by Emily Burghart 1k
Sun Feb 02, 2020 8:07 pm
Forum: Phase Changes & Related Calculations
Topic: Reversible and Irreversible
Replies: 5
Views: 62

Re: Reversible and Irreversible

Would irreversible reactions occur in open containers then? If the pressure is constant is it always a irreversible reaction? In open containers I believe you would use the irreversible equation since you are losing energy in the form of heat to the surroundings. According to the first comment, tha...
by Emily Burghart 1k
Sun Feb 02, 2020 7:48 pm
Forum: Phase Changes & Related Calculations
Topic: phase change from liquid to vapor
Replies: 8
Views: 81

Re: phase change from liquid to vapor

Visible on the heating curve that we looked at in class, there is a significant amount of energy stored in vaporized water. When this vapor comes into contact with human skin (which is significantly cooler than the vapor) the vapor releases vast amounts of energy to return to its liquid state, which...
by Emily Burghart 1k
Mon Jan 27, 2020 10:46 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: "Breaking bonds is always endothermic"
Replies: 6
Views: 70

Re: "Breaking bonds is always endothermic"

In LS we learned that there is an input of energy to overcome the energy barrier, and that energy was released. But the energy put in or released depends on the type of bond that is broken. Determining enthalpy depends on the difference of energy between input to break and output to form these bonds.
by Emily Burghart 1k
Mon Jan 27, 2020 10:35 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Signs for enthalpy
Replies: 8
Views: 51

Re: Signs for enthalpy

When a reaction has a negative enthalpy, it is considered ectothermic because it is releasing heat. You can think of how ecto sounds slightly like exit, and the negative sign as subtracting heat from a system and sending it into its surrounding environment. For endothermic, think of endo like enter....
by Emily Burghart 1k
Mon Jan 20, 2020 11:51 am
Forum: Ideal Gases
Topic: Partial Pressures
Replies: 4
Views: 58

Re: Partial Pressures

In a chemical reaction, if one reactant is increased in pressure, the other will decrease to try and balance it, but ultimately the concentration then becomes higher and the equilibrium shifts to the products where pressure increases.
by Emily Burghart 1k
Mon Jan 20, 2020 11:34 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding Inert Gas
Replies: 9
Views: 73

Re: Adding Inert Gas

Adding an inert gas, a noble gas, has no change on the chemical system.
by Emily Burghart 1k
Mon Jan 20, 2020 11:32 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier Principle
Replies: 4
Views: 53

Re: Le Chatelier Principle

When considering temperature, pressure, and concentration, it is important to note that pressure and concentration both only change where equilibrium lies on the equilibrium constant. If you were to increase pressure or concentration in one part of the equation, pressure or concentration would decre...
by Emily Burghart 1k
Mon Jan 20, 2020 11:12 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% rule
Replies: 3
Views: 30

Re: 5% rule

The coefficients are taken into account when calculating the concentration of the reactants and the products. Once you have done that, I don't think you need to consider the coefficients again. For example, if you have calculated that there was x amount of product at equilibrium and y amount initia...
by Emily Burghart 1k
Sun Jan 12, 2020 10:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration
Replies: 5
Views: 32

Re: Concentration

A change in concentration does not cause Kc to change because equilibrium adjusts until the standard Kc rate is met. However, an increase in temperature will cause Kc to shift towards the reactants and vice versa.
by Emily Burghart 1k
Sun Jan 12, 2020 9:44 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Situations in which Q=K
Replies: 7
Views: 45

Re: Situations in which Q=K

When Q=K the reaction is at equilibrium meaning that the forward and reverse reactions are happening at the same rate. This does not mean that they are not occurring, but rather [R] and [P] are being formed at the same time, and neither is being formed more than the other.
by Emily Burghart 1k
Sun Jan 12, 2020 9:31 pm
Forum: Ideal Gases
Topic: PV = nRT
Replies: 16
Views: 139

Re: PV = nRT

P- Pressure
V- Volume
n- Amount in moles
R- The ideal gas constant (depends on the units you are using)
T- Temperature

P and V are inversely related. Assuming a constant temperature, when pressure increases volume decreases and so forth.
by Emily Burghart 1k
Sun Jan 12, 2020 12:17 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and relation of [R] to [P]
Replies: 5
Views: 81

Re: Q and relation of [R] to [P]

For this problem we are only looking at the change in the P or R values of the Q equation, using K as a fixed ratio. Your K value is the fixed ratio between the left and right sides when at equilibrium. While Q is also a ratio between the [R] and [P] but the ratio might not be at equilibrium. This m...
by Emily Burghart 1k
Sat Jan 11, 2020 10:55 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 19
Views: 183

Re: Le Chatelier's Principle

Is it appropriate to consider Le Chatelier's Principle as a ratio?
I.e. determining the change of one value would aid in determining the other values and thus, the equilibrium?

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