Search found 60 matches

by Deepika Pugalenthi 1A
Fri Mar 15, 2019 2:17 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Purpose of Arrhenius equation
Replies: 2
Views: 51

Purpose of Arrhenius equation

By solving for the frequency factor by using the Arrhenius equation, what does this tell us about the overall reaction?
by Deepika Pugalenthi 1A
Fri Mar 15, 2019 2:14 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst or intermediate
Replies: 3
Views: 53

Re: catalyst or intermediate

Catalysts are on the reactant side of the initial elementary step of a reaction and are used up in following elementary steps. They are produced as a by-product in the following steps. However, intermediates have to be formed first and then only used up in elementary steps of the reaction. The best ...
by Deepika Pugalenthi 1A
Fri Mar 15, 2019 2:11 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 3
Views: 65

Re: Catalysts

Catalysts are part of the reactants of the initial elementary step and are used up in following elementary steps. Therefore, the catalyst is not part of the overall reaction since it is used up in the elementary steps. The purpose of the catalyst is to lower the activation energy and speed up the ov...
by Deepika Pugalenthi 1A
Sat Mar 09, 2019 3:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: reactions with multiple reactants
Replies: 1
Views: 62

reactions with multiple reactants

To find the order of a reactant within a reaction that has multiple reactants, how do make one reactant concentration small and the others large?
by Deepika Pugalenthi 1A
Sat Mar 09, 2019 3:47 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining the order of the reaction
Replies: 2
Views: 59

Determining the order of the reaction

Are there other ways to determine the order of the reaction other than plotting to see which leads to a straight line?
by Deepika Pugalenthi 1A
Sat Mar 09, 2019 3:41 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining the slow step
Replies: 2
Views: 54

Determining the slow step

To identify the slow step in a series of reactions, do you compare the rate constant of each step or do you have to use experimental data to determine the slow step?
by Deepika Pugalenthi 1A
Sat Mar 02, 2019 11:22 am
Forum: General Rate Laws
Topic: Point of equilibrium
Replies: 5
Views: 83

Point of equilibrium

When looking at a graph of the progression of a reaction over time, how do you know when equilibrium has been reached by the reaction?
by Deepika Pugalenthi 1A
Sat Mar 02, 2019 11:19 am
Forum: General Rate Laws
Topic: rate law
Replies: 3
Views: 76

rate law

What information does the rate law help us identify about a certain reaction?
by Deepika Pugalenthi 1A
Fri Mar 01, 2019 12:12 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test #2
Replies: 10
Views: 208

Re: Test #2

We'll probably get our tests back during discussion sections next week.
by Deepika Pugalenthi 1A
Fri Feb 22, 2019 12:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Favor ability of Cell portential
Replies: 5
Views: 102

Re: Favor ability of Cell portential

When cell potential is positive, it indicates a spontaneous reaction because Gibbs free energy is negative. This is due to the equation for work done, or work max (work max = -charge x E). When incorporating Faraday into the equation, work max = -nFE. Work max equals Gibbs free energy due to the red...
by Deepika Pugalenthi 1A
Fri Feb 22, 2019 12:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell potential and Gibbs free energy
Replies: 2
Views: 53

Cell potential and Gibbs free energy

When the reaction is spontaneous, why does cell potential have to be positive?
by Deepika Pugalenthi 1A
Fri Feb 22, 2019 12:07 pm
Forum: Balancing Redox Reactions
Topic: standard reduction potential
Replies: 2
Views: 52

standard reduction potential

When calculating standard reduction potential, is there ever an instance when you would multiply or divide the standard reduction potential? Or is it only sign change based on which direction the reaction proceeds?
by Deepika Pugalenthi 1A
Fri Feb 15, 2019 12:22 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: enthalpy, entropy, Gibbs Free Energy signs
Replies: 3
Views: 69

enthalpy, entropy, Gibbs Free Energy signs

For what signs of enthalpy, entropy, and Gibbs Free Energy is a reaction spontaneous and when is it not spontaneous?
by Deepika Pugalenthi 1A
Fri Feb 15, 2019 12:21 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: work and Gibbs Free Energy
Replies: 2
Views: 77

work and Gibbs Free Energy

How is work equivalent to Gibbs Free Energy? Is work done by the system when Gibbs Free Energy is positive?
by Deepika Pugalenthi 1A
Fri Feb 15, 2019 12:19 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy graph
Replies: 2
Views: 52

Gibbs Free Energy graph

For the graph Professor Lavelle drew for Gibbs Free Energy in class, the reaction is spontaneous as long as it's approaching equilibrium but not when it is at equilibrium?
by Deepika Pugalenthi 1A
Sat Feb 09, 2019 5:17 pm
Forum: Calculating Work of Expansion
Topic: Derivations - Midterm
Replies: 3
Views: 72

Derivations - Midterm

For the midterm, do we need to know the derivations of the formulas or do we just have to know how to use them?
by Deepika Pugalenthi 1A
Sat Feb 09, 2019 5:14 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Difference in pathways
Replies: 1
Views: 45

Difference in pathways

what is the difference between reversible and irreversible pathway?
by Deepika Pugalenthi 1A
Fri Feb 01, 2019 12:20 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 3 methods for enthalpy calculation
Replies: 10
Views: 179

3 methods for enthalpy calculation

In class, Professor Lavelle taught three ways to calculate enthalpy. Which method is the most effective and during a test will be told which method to use?
by Deepika Pugalenthi 1A
Fri Feb 01, 2019 12:14 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm
Replies: 4
Views: 110

Re: Midterm

The midterm will be week 6 on Wednesday, February 13, 6-8 PM. You can view the dates for exams on the chem 14B webpage.
by Deepika Pugalenthi 1A
Fri Feb 01, 2019 12:12 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Universe as a Thermodynamic System
Replies: 2
Views: 55

Re: Universe as a Thermodynamic System

The universe is considered an isolated system because the energy of the universe is constant. This matches with the definition of an isolated system, which is that energy is not exchanged with the surroundings, thus staying constant.
by Deepika Pugalenthi 1A
Sat Jan 26, 2019 4:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: states of reactants and products
Replies: 3
Views: 65

states of reactants and products

When calculating the net delta H using Hess's method, is it required that all the reactants and products be in the same state (liquid, gas, solid)?
by Deepika Pugalenthi 1A
Sat Jan 26, 2019 4:27 pm
Forum: Phase Changes & Related Calculations
Topic: work and heat
Replies: 2
Views: 58

work and heat

Why do work and heat depend on the path instead of the state properties?
by Deepika Pugalenthi 1A
Sat Jan 26, 2019 4:24 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bonds being broken in reaction
Replies: 4
Views: 77

Bonds being broken in reaction

When calculating bond enthalpies, what is the relevance of knowing that the entire bond is broken? Is it to understand the conceptual aspect or do the bonds play a role in the calculation?
by Deepika Pugalenthi 1A
Fri Jan 18, 2019 12:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Buffers - weak acid
Replies: 4
Views: 89

Buffers - weak acid

When making buffers, it's always a weak acid and a salt. To make buffers of varying pH, the only factor changing is the strength of the weak acid?
by Deepika Pugalenthi 1A
Fri Jan 18, 2019 12:15 pm
Forum: Ideal Gases
Topic: Percentage protonated
Replies: 2
Views: 88

Percentage protonated

What is the significance of finding the percentage protonated? Does it help check if the values are valid or plausible?
by Deepika Pugalenthi 1A
Fri Jan 18, 2019 12:10 pm
Forum: Ideal Gases
Topic: [Products] over [Reactants] cancellations
Replies: 3
Views: 82

Re: [Products] over [Reactants] cancellations

Think about the million dollar example Professor Lavelle gave during lecture. If a millionaire gives a poor man a thousand dollars, it seems like a lot to the poor man but doesn't seem that substantial to the millionaire. This is due to the fact that a thousand dollars doesn't make a significant dif...
by Deepika Pugalenthi 1A
Fri Jan 11, 2019 12:19 pm
Forum: Ideal Gases
Topic: Pressure and volume
Replies: 4
Views: 91

Pressure and volume

Are pressure and volume inversely related when identifying the direction a reaction is going to go when changing either factor? For example, if I want to increase the pressure, the reaction would move to the side with fewer moles and vice versa?
by Deepika Pugalenthi 1A
Fri Jan 11, 2019 12:08 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1193

Re: Q and K [ENDORSED]

There is no difference in the formulas for Q and K. The main difference lies in what Q and K are calculated for. K is the equilibrium constant, therefore it can only be applied to identify when the reaction is at equilibrium. Q, on the other hand, is the reaction quotient and can be calculated at an...
by Deepika Pugalenthi 1A
Fri Jan 11, 2019 12:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Activity in reactions
Replies: 2
Views: 45

Activity in reactions

In lecture and discussion, it was mentioned that there was activity in reactions but aren't required to be incorporated in calculating the equilibrium constant. Can someone explain to me what exactly activity is?
by Deepika Pugalenthi 1A
Wed Dec 05, 2018 10:37 am
Forum: Lewis Acids & Bases
Topic: Resonance in acids
Replies: 3
Views: 105

Resonance in acids

How does resonance affect the strength of an acid?
by Deepika Pugalenthi 1A
Wed Dec 05, 2018 10:35 am
Forum: Lewis Acids & Bases
Topic: Inductiveness vs. atomic radii
Replies: 1
Views: 57

Inductiveness vs. atomic radii

When trying to list molecules from weak to strong acid, do we take inductiveness into consideration first or the atomic radii? Does one outweigh the other or is it based on what molecules are being compared?
by Deepika Pugalenthi 1A
Wed Dec 05, 2018 10:31 am
Forum: Naming
Topic: Knowing oxidation states
Replies: 11
Views: 146

Re: Knowing oxidation states

My TA said there will be questions about oxidation states on the test and that the best way to know them is to memorize the formula in the book. The question on the test will be plug and chug. It would be helpful to know the oxidation states of certain common elements that come up with coordinate co...
by Deepika Pugalenthi 1A
Thu Nov 29, 2018 7:45 pm
Forum: Bond Lengths & Energies
Topic: Bond Length Trends (Molar Mass)
Replies: 1
Views: 199

Re: Bond Length Trends (Molar Mass)

When I read that in the book, I thought of heavy and light as referring to the number of electrons the atoms had. The more electrons an atom has (heavier), the larger the radius will be, leading to an increased bond length. And the reverse applies for atoms with a lower number of electrons (lighter)...
by Deepika Pugalenthi 1A
Thu Nov 29, 2018 7:37 pm
Forum: Naming
Topic: Transition metal oxidation states
Replies: 3
Views: 62

Transition metal oxidation states

Why do transition metals have many oxidation states?
by Deepika Pugalenthi 1A
Thu Nov 29, 2018 7:34 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating ligands
Replies: 1
Views: 20

Chelating ligands

Why do chelating ligands bind cations tightly?
by Deepika Pugalenthi 1A
Sun Nov 25, 2018 11:48 am
Forum: Hybridization
Topic: Test 3
Replies: 13
Views: 195

Re: Test 3

For test 3, we need to know 3.12 and onwards in chapter 3 and all of chapter 4. Professor Lavelle said that as long as we know how to identify the molecular shape and the general angles, we're good. We need to draw Lewis structures, but I don't think you need to know how to draw hybridizations.
by Deepika Pugalenthi 1A
Sun Nov 25, 2018 10:48 am
Forum: Hybridization
Topic: Carbon rotation in C2H4
Replies: 2
Views: 47

Carbon rotation in C2H4

In class, Professor Lavelle said that if the 2 carbon atoms in C2H4 rotate, then the pi bond would break. Why would the rotation affect the strength of the pi bond?
by Deepika Pugalenthi 1A
Sun Nov 25, 2018 10:47 am
Forum: Hybridization
Topic: Octet Expansion
Replies: 6
Views: 113

Octet Expansion

Why is the d-orbital required for octet expansion?
by Deepika Pugalenthi 1A
Sat Nov 17, 2018 3:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw shape
Replies: 2
Views: 54

Seesaw shape

Do molecules usually have the seesaw shape when they have one lone pair?
by Deepika Pugalenthi 1A
Sat Nov 17, 2018 3:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 5
Views: 83

Bond angles

For bond angles, do we only have to know 120 degrees and 109.5 degrees? Is there any formula as to how to determine these bond angles?
by Deepika Pugalenthi 1A
Sat Nov 17, 2018 3:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape
Replies: 2
Views: 56

Molecular shape

Why is it that the shape of the molecule contributes to the strength of interactions?
by Deepika Pugalenthi 1A
Fri Nov 09, 2018 9:35 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Disperson forces
Replies: 4
Views: 95

Disperson forces

In class, Professor Lavelle said that increasing the strength of dispersion forces explains why F2 and Cl2 are gases while Br2 is a liquid. What do dispersion forces have to do with the state of these diatomic molecules?
by Deepika Pugalenthi 1A
Fri Nov 09, 2018 9:28 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: electron distortion
Replies: 4
Views: 126

electron distortion

Why do electrons in one atom/molecule cause electron distortion in a nearby atom/molecule?
by Deepika Pugalenthi 1A
Fri Nov 09, 2018 9:19 am
Forum: Bond Lengths & Energies
Topic: Dipole interaction
Replies: 3
Views: 94

Dipole interaction

During the lecture, Professor Lavelle went over the different interactions that give rise to attractive forces? I didn't understand how the dipole-dipole and the dipole-induced dipole interactions worked. Can someone please explain that?
by Deepika Pugalenthi 1A
Wed Oct 31, 2018 10:31 am
Forum: Electronegativity
Topic: electronegativity in lewis structures
Replies: 2
Views: 94

Re: electronegativity in lewis structures

In class, Professor Lavelle said to use the atom with the lowest ionization energy as the central atom in Lewis structures. I think we use ionization energy because it determines the strength of the electrostatic charge and the lower it is, less of a hold it will have on the electrons.
by Deepika Pugalenthi 1A
Wed Oct 31, 2018 10:23 am
Forum: Resonance Structures
Topic: resonance hybrids
Replies: 4
Views: 120

resonance hybrids

What does the resonance hybrid exactly show? Does it show the attraction of electrons within the molecule through the dotted lines? Thank you!
by Deepika Pugalenthi 1A
Wed Oct 31, 2018 10:16 am
Forum: Electronegativity
Topic: Periodic Trends [ENDORSED]
Replies: 3
Views: 134

Re: Periodic Trends [ENDORSED]

Electronegativity is how strongly atoms attract electrons to themselves. As you go from left to right, the number of protons in the nucleus increases. Since protons are positively charged and are attracted to the negatively charged electrons, electronegativity will in turn increase as well. Electron...
by Deepika Pugalenthi 1A
Wed Oct 24, 2018 10:23 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave functions
Replies: 4
Views: 102

Re: Wave functions

We don't need to know how to solve wave functions because that goes into double derivatives and some complex math. The main concept you have to know about wave function is how it relates to the quantum numbers. Schrodinger's wave function gives rise to the three quantum numbers n, l, and ml. We just...
by Deepika Pugalenthi 1A
Wed Oct 24, 2018 10:18 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Shielding effect
Replies: 6
Views: 220

Shielding effect

How does shielding work and how does that affect electrostatic attraction of the electrons to the nucleus? Thank you!
by Deepika Pugalenthi 1A
Wed Oct 24, 2018 10:16 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question About Valence Electrons
Replies: 1
Views: 57

Re: Question About Valence Electrons

Valence electrons are the electrons located on the outermost shell, the shell being identified by the principal quantum number, n. In the example you gave for phosphorus, you would consider the valence electrons for the whole energy level of n=3. Phosphorus would have 5 valence electrons. Its n=1 an...
by Deepika Pugalenthi 1A
Sat Oct 20, 2018 11:34 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Coulomb's Law
Replies: 3
Views: 62

Coulomb's Law

What is the significance of using Coulomb's law in identifying electrostatic charge? What do you do with the values that you obtain from the equation? Thank you!
by Deepika Pugalenthi 1A
Sat Oct 20, 2018 11:29 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Test Two
Replies: 2
Views: 60

Re: Test Two

During the lecture, he said that all quantum material would be covered on the upcoming test. Since he did slightly touch on electron configuration in lecture, I would say to study it to be safe and prepared for the test.
by Deepika Pugalenthi 1A
Sat Oct 20, 2018 11:26 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Symmetry in electron density distribution
Replies: 3
Views: 214

Symmetry in electron density distribution

What does it mean when the electron-density distribution is symmetrical versus non-symmetrical? Thank you!
by Deepika Pugalenthi 1A
Sat Oct 13, 2018 3:28 pm
Forum: DeBroglie Equation
Topic: De Broglie wavelength - when can it be seen
Replies: 5
Views: 63

De Broglie wavelength - when can it be seen

During lecture, Professor Lavelle was saying that any wavelength smaller than 10^-18 cannot be seen. What does it mean for a wavelength to be seen? Thank you!
by Deepika Pugalenthi 1A
Fri Oct 12, 2018 4:53 pm
Forum: Properties of Light
Topic: Photon energy
Replies: 2
Views: 44

Photon energy

Why do photons give off only positive energy?
by Deepika Pugalenthi 1A
Thu Oct 11, 2018 2:46 pm
Forum: Einstein Equation
Topic: Units for v(frequency)
Replies: 11
Views: 175

Re: Units for v(frequency)

s^-1 and Hz can be uses interchangeably because they are the same thing. Usually, in problems it is given in Hz so I would recommend using Hz instead of s^-1.
by Deepika Pugalenthi 1A
Fri Oct 05, 2018 9:57 am
Forum: Empirical & Molecular Formulas
Topic: Empirical formula set up
Replies: 9
Views: 197

Empirical formula set up

Why do we have to use 100 grams as the starting point when trying to find the empirical formula? Thank you!!
by Deepika Pugalenthi 1A
Fri Oct 05, 2018 9:48 am
Forum: Significant Figures
Topic: Zeros in sig figs
Replies: 4
Views: 112

Zeros in sig figs

I'm confused about when to count the zeros as significant figures and when not to. Can somebody please explain this concept to me? Thank you!
by Deepika Pugalenthi 1A
Fri Oct 05, 2018 9:33 am
Forum: Significant Figures
Topic: Scientific Notation
Replies: 7
Views: 143

Re: Scientific Notation

I use scientific notation primarily when there's multiple zeros after the decimal point before getting to the exact numbers. For example, if the answer is 0.00072, I would write it in scientific notation instead of writing out all the zeros in order to get two sig figs.

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