Search found 49 matches

by Kaileigh Yang 2I
Fri Mar 16, 2018 11:09 am
Forum: *Electrophiles
Topic: what is going to be on the final? [ENDORSED]
Replies: 12
Views: 682

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

It might be a good idea to also look at the practice final posted on chemistry community!
by Kaileigh Yang 2I
Fri Mar 16, 2018 11:08 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Rate determining step
Replies: 2
Views: 116

Re: Rate determining step

I think it means the slow step.
by Kaileigh Yang 2I
Fri Mar 16, 2018 11:06 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: sketching reaction profiles
Replies: 2
Views: 107

Re: sketching reaction profiles

When sketching a reaction profile, I think it is just important to remember that if the reaction is exothermic, the reactants will start off at a higher point than the products whereas in an endothermic reaction, the reactants will start of lower than the products. In addition, the humps that mark t...
by Kaileigh Yang 2I
Fri Mar 16, 2018 11:02 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: When to use standard potentials and when to balance
Replies: 2
Views: 117

Re: When to use standard potentials and when to balance

It's just like balancing an equation to complete it. Just remember to balance according to whether it is a basic or acidic solution.
by Kaileigh Yang 2I
Fri Mar 16, 2018 11:01 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Book Thinking Point
Replies: 1
Views: 203

Re: Book Thinking Point

I'm not sure if this is correct, but I wonder if it is because even as the molecules move farther apart and the vibrational motions of the molecules increase, it is the change that stays the same and therefore potential energy does not change?
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:59 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.67
Replies: 3
Views: 127

Re: 15.67

The question is asking for the factor that will increase the rate of reaction therefore using a ratio between the rates of the catalyzed and un-catalyzed will show the multiple between the two.
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:57 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Question 15.87
Replies: 1
Views: 87

Re: Question 15.87

It is simply asking how, under different conditions such as change in concentration, the reaction mechanism might change. For example, in the book it says that in a dilute solution, kinetic data is not able to distinguish between different mechanisms whereas in a highly concentrated solution, the wa...
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:53 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady-State Approximation vs. Pre-equilibrium Condition
Replies: 4
Views: 254

Re: Steady-State Approximation vs. Pre-equilibrium Condition

Typically, if the reaction has a fast first step, it is safe to use a pre-equilibrium approximation. On the other hand, if the reaction has a slow first step, a steady state approximation is used instead.
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:50 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: trend for temp and activation energy
Replies: 3
Views: 125

Re: trend for temp and activation energy

Yes, at higher temperatures there is sufficient energy to overcome the larger activation energy.
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:49 am
Forum: General Science Questions
Topic: Grade
Replies: 8
Views: 671

Re: Grade

One TA I talked to said that there was no curve so it is simply dependent on the number of points you received over the quarter.
by Kaileigh Yang 2I
Fri Mar 16, 2018 10:48 am
Forum: *Aldehydes
Topic: Toxicity
Replies: 1
Views: 247

Re: Toxicity

I believe the toxicity of an aldehyde is more dependent on the type and quantity rather than assuming as a general rule.
by Kaileigh Yang 2I
Thu Mar 01, 2018 10:37 am
Forum: First Order Reactions
Topic: reaction order
Replies: 2
Views: 118

Re: reaction order

Reaction orders are typically positive numbers but it is possible for them to be zero, fractional, or negative.
by Kaileigh Yang 2I
Thu Mar 01, 2018 10:35 am
Forum: First Order Reactions
Topic: Pseudo-First Order Reaction [ENDORSED]
Replies: 4
Views: 180

Re: Pseudo-First Order Reaction [ENDORSED]

I guess it's kind of related to the second order reaction because of the fact that you have more than one reactant.
by Kaileigh Yang 2I
Thu Mar 01, 2018 10:32 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalytic Reactions
Replies: 2
Views: 110

Re: Catalytic Reactions

A catalytic reaction is one in which something is added to the reaction to increase the rate of that reaction. Other good examples of catalytic reactions include enzymes in biochemical reactions.
by Kaileigh Yang 2I
Thu Mar 01, 2018 10:26 am
Forum: Second Order Reactions
Topic: Half Life
Replies: 2
Views: 129

Re: Half Life

Also, if you simply plot the half life reactions for all three types of reactions you can see that in the zero order reaction and the second order reaction, the slope changes as the concentration changes, whereas in the first order reaction graph, the length of the half-life remains at a constant, i...
by Kaileigh Yang 2I
Thu Mar 01, 2018 10:20 am
Forum: Second Order Reactions
Topic: Example?
Replies: 4
Views: 178

Re: Example?

An example of a second order reaction is the formation of oxygen molecules from the combustion of oxygen atoms and ozone (O + O3 → O2 + O2).
by Kaileigh Yang 2I
Wed Feb 21, 2018 4:46 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15 B
Replies: 1
Views: 97

Re: 14.15 B

I think it's because H+ and O2 are what form the H2O molecule, which is why we know to include it in one of the half reactions.
by Kaileigh Yang 2I
Wed Feb 21, 2018 4:44 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15b
Replies: 1
Views: 78

Re: 14.15b

I think based off the equation and which equation needs to be reduced to receive a positive Ecell, one can determine which reaction is at the anode and which reaction is at the cathode.
by Kaileigh Yang 2I
Wed Feb 21, 2018 4:42 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 2
Views: 92

Re: Galvanic Cells

Yes, galvanic cells always have a positive potential difference. Because there are only two ways to combine the two, if one way makes it negative, flip one of them for a positive output.
by Kaileigh Yang 2I
Wed Feb 21, 2018 4:39 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: What is n when finding Standard Gibbs Rxn
Replies: 1
Views: 58

Re: What is n when finding Standard Gibbs Rxn

n is the number of electrons transferred total between the half reactions.
by Kaileigh Yang 2I
Sun Feb 04, 2018 7:31 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Using dS vs change in S
Replies: 3
Views: 129

Re: Using dS vs change in S

I think dS is mainly used in proofs as a part of integral calculus and deltaS is what we are actually solving for.
by Kaileigh Yang 2I
Sun Feb 04, 2018 7:25 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Question about "Real Processes"
Replies: 3
Views: 118

Re: Question about "Real Processes"

All real processes cannot be reversible because it would need to take the same process to return to its original state, however, this not always the case for more complex processes.
by Kaileigh Yang 2I
Sun Feb 04, 2018 7:21 pm
Forum: Calculating Work of Expansion
Topic: Calculating work of expansion on the exam
Replies: 2
Views: 102

Re: Calculating work of expansion on the exam

Otherwise, they would probably be very simple integrals I assume.
by Kaileigh Yang 2I
Fri Feb 02, 2018 12:48 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Exergonic [ENDORSED]
Replies: 5
Views: 156

Re: Exergonic [ENDORSED]

An example of an exergonic reaction in our body is cellular respiration. In breathing, we are releasing energy into our surroundings. Another example of an exergonic reaction is combustion.
by Kaileigh Yang 2I
Fri Feb 02, 2018 12:43 pm
Forum: Phase Changes & Related Calculations
Topic: Phase change
Replies: 4
Views: 149

Re: Phase change

You know the phase change would occur because it's changing from a solid to a liquid. It is not only increasing in temperature, the heat required to change the physical form of the substance would need to be taken into account as well.
by Kaileigh Yang 2I
Fri Feb 02, 2018 12:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Using the Kan't Hoff Equation to Calculate the Change in Concentration
Replies: 1
Views: 67

Re: Using the Kan't Hoff Equation to Calculate the Change in Concentration

Because deltaS and deltaH are the changes in entropy and enthalpy, it is not an issue of whether or not they would be constant because they are the difference in the initial and final states which would vary between each problem you do.
by Kaileigh Yang 2I
Sun Jan 28, 2018 11:06 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.1
Replies: 3
Views: 133

Re: 9.1

Usually there if there is a change in temperature involved in an equation, either unit is acceptable because it's only the change that is important.
by Kaileigh Yang 2I
Sun Jan 28, 2018 11:05 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Definition of Entropy
Replies: 10
Views: 267

Re: Definition of Entropy

Entropy of a system can be defined as being the thermodynamic quantity that demonstrates how a system's thermal energy cannot be converted into mechanical work. Usually it is interpreted as being the degree of disorder or randomness in a system.
by Kaileigh Yang 2I
Sun Jan 28, 2018 10:58 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 9.19
Replies: 4
Views: 210

Re: 9.19

Do you have to cool it to start backwards from 85 degrees C, since we are given the standard entropy of vaporization at 100 degrees C?
by Kaileigh Yang 2I
Sun Dec 10, 2017 2:03 am
Forum: Lewis Structures
Topic: NO2 Lewis Structure
Replies: 2
Views: 343

Re: NO2 Lewis Structure

In addition, it's a good idea to check the formal charge of the compound.
by Kaileigh Yang 2I
Sun Dec 10, 2017 1:49 am
Forum: Lewis Acids & Bases
Topic: Determine Lewis Acid
Replies: 13
Views: 537

Re: Determine Lewis Acid

A Lewis acid is an electron acceptor.
by Kaileigh Yang 2I
Sun Dec 10, 2017 1:45 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong or weak acids/ bases
Replies: 6
Views: 396

Re: Strong or weak acids/ bases

A strong acid also typically has weaker electron affinity because it makes it easier to break off completely into its ions.
by Kaileigh Yang 2I
Sun Dec 10, 2017 1:43 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Test 4 #6
Replies: 2
Views: 270

Re: Test 4 #6

With four values, you would have to calculate the value of Q for the initial molar concentrations and compare it to K to determine which direction the reaction is going in. Then, from there you can solve the rest of the ICE table normally.
by Kaileigh Yang 2I
Fri Dec 08, 2017 4:39 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted and Lewis Acids
Replies: 3
Views: 200

Re: Bronsted and Lewis Acids

Based on the definitions, I don't believe this can be true. Bronsted-Lowry bases are bases because they combine with hydrogen ions, which is possible due to the lone pair of electrons they have, which is consistent with the Lewis acid definition.
by Kaileigh Yang 2I
Fri Dec 08, 2017 4:30 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: number of oxygen atoms effect on acidity
Replies: 1
Views: 156

Re: number of oxygen atoms effect on acidity

The bond strength of O - H in the acid and the stability of the conjugate base determine the strength of the acid. When there are more electronegative oxygen atoms pulling away electron density from the O - H bond, the bond is weakened and can therefore break more easily. Charge density might also b...
by Kaileigh Yang 2I
Thu Dec 07, 2017 11:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Question 12.55
Replies: 1
Views: 96

Re: Question 12.55

You would need to use an ICE table to calculate the H3O+ concentration which you can use to divide over the initial concentration of CH3COOH x 100 to get the percentage deprotonation.
by Kaileigh Yang 2I
Thu Dec 07, 2017 11:57 pm
Forum: Lewis Acids & Bases
Topic: 12.17
Replies: 2
Views: 170

Re: 12.17

For these types of questions, typically the periodic table and an element's metallic or nonmetallic properties are used to determine whether or not something is acidic, basic, or amphoteric.
by Kaileigh Yang 2I
Thu Dec 07, 2017 11:55 pm
Forum: Lewis Acids & Bases
Topic: 12.13
Replies: 5
Views: 303

Re: 12.13

Ag+ is a Lewis acid because if Ag+ accepts an electron it would become just Ag. In one example of 2NH3 + Ag+ --> [Ag(NH3)2]+, the lone pair of e- on NH3 would go to the Ag+.
by Kaileigh Yang 2I
Thu Dec 07, 2017 11:52 pm
Forum: Bronsted Acids & Bases
Topic: Lone Pair of Bronsted
Replies: 1
Views: 101

Re: Lone Pair of Bronsted

A Bronsted base requires a lone pair of electrons to bond to the H+ in order for it to be capable of accepting a proton.
by Kaileigh Yang 2I
Sun Dec 03, 2017 1:25 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Problem 55 Part D
Replies: 1
Views: 114

Re: Problem 55 Part D

Certain substances are bound very tightly together and do not split apart easily. Take for example, CH4 or methane, which is less acidic since all four hydrogen atoms are held very closely to the carbon atom and therefore does not break off as easily. On the other hand, substances held together by p...
by Kaileigh Yang 2I
Sun Dec 03, 2017 12:29 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and pOH
Replies: 10
Views: 405

Re: pH and pOH

The pH scale measures the H+ concentration while the pOH scale measures the OH- concentration. Depending on which value you are given, one way to calculate the pH or the pOH of a solution is pH + pOH = 14.
by Kaileigh Yang 2I
Sat Nov 04, 2017 5:41 pm
Forum: Administrative Questions and Class Announcements
Topic: 14B and 14BL
Replies: 3
Views: 231

Re: 14B and 14BL

I heard several people take 14B and 14BL in separate quarters.
by Kaileigh Yang 2I
Sat Oct 28, 2017 4:54 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation Applications [ENDORSED]
Replies: 7
Views: 367

Re: Shrodinger Equation Applications [ENDORSED]

Doesn't the Shrodinger equation only apply to particle in a box and certain laws of conservation of energy?
by Kaileigh Yang 2I
Sat Oct 28, 2017 4:39 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence Electrons [ENDORSED]
Replies: 1
Views: 149

Re: Valence Electrons [ENDORSED]

The valence electrons are just the electrons in the outer shell, so if it is the outermost, then it is included.
by Kaileigh Yang 2I
Sat Oct 21, 2017 3:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework for Test #3
Replies: 1
Views: 186

Re: Homework for Test #3

I believe we'll be finishing up the rest of Quantum World for the next test (which I think is our mid-term).
by Kaileigh Yang 2I
Sat Oct 21, 2017 3:31 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals and Electron Configuration
Replies: 3
Views: 169

Re: Orbitals and Electron Configuration

I think it can be written either way. Distinguishing between the x and y orbitals of the 2p shell just clarifies where exactly the electrons go.
by Kaileigh Yang 2I
Sat Oct 14, 2017 4:27 pm
Forum: Photoelectric Effect
Topic: Photoelectric effect [ENDORSED]
Replies: 1
Views: 229

Re: Photoelectric effect [ENDORSED]

1 nm = 10^-9 m
by Kaileigh Yang 2I
Sat Oct 14, 2017 2:56 pm
Forum: Photoelectric Effect
Topic: general curiosity about atom stability [ENDORSED]
Replies: 2
Views: 158

Re: general curiosity about atom stability [ENDORSED]

I'm not sure if this answers your question exactly but an atom is most stable when their outermost energy level is either empty or completely full.
by Kaileigh Yang 2I
Wed Oct 11, 2017 4:59 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Condition/Rydberg Constant
Replies: 2
Views: 214

Re: Bohr Condition/Rydberg Constant

I think the Bohr model simply explained the structure of the Rydberg formula and proved the observed results found from the model.

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