Search found 22 matches

by Ian Hurst 3L
Fri Mar 11, 2016 8:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework 14.15C
Replies: 1
Views: 146

Homework 14.15C

(For homework 14.15c) In the solution manual it lists KOH (aq) as one of the aqueous species. I am confused as to why this is there. Is this a typo?
by Ian Hurst 3L
Mon Mar 07, 2016 12:37 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche vs Anti Stability
Replies: 1
Views: 729

Gauche vs Anti Stability

The energy diagram in the book shows that gauche and anti configurations are not equally stable for 1,2-dibromoethane. Why is the anti configuration the most stable while the gauche is sightly less stable? Is this because of torsional or steric strain? or both?

Thanks
by Ian Hurst 3L
Mon Mar 07, 2016 12:25 am
Forum: Administrative Questions and Class Announcements
Topic: Video Competition
Replies: 66
Views: 25028

Re: Video Competition

First Order Rate Law

Created by-

Ian Hurst
Lovelyn Edillo
Vinay Sharma

Hope you guys enjoy!
by Ian Hurst 3L
Sun Mar 06, 2016 1:42 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Sawhorse vs Newman Projection
Replies: 1
Views: 324

Sawhorse vs Newman Projection

I understand that sawhorse projections are drawn at an angle for the best representation of a structure while Newman projections utilize line intersections to represent carbon bonds. Are there situations where one is preferred over the other? In what situation is optimal to use a sawhorse projection...
by Ian Hurst 3L
Sat Feb 27, 2016 6:28 pm
Forum: *Alkanes
Topic: Determining Priority
Replies: 2
Views: 249

Determining Priority

How do we determine which functional group has priority? Do we just have to memorize the list and just know, for example, that carboxylic groups have higher priority than alcohol groups? Is there another way to figure it out by looking at atomic mass or something? Also, for (E)-4-methlycyclopent-2-e...
by Ian Hurst 3L
Sun Feb 21, 2016 10:53 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Homogeneous and Heterogeneous Catalysts
Replies: 3
Views: 667

Re: Homogeneous and Heterogeneous Catalysts

In the course reader (page 78), it explains that reactants sit on the surface of the catalyst in a reaction (and this is known as adsorption). Although it may look like a typo, adsorption is actually a term that refers to a substance that sticks to the surface (so in a reaction, reactants sticking t...
by Ian Hurst 3L
Sun Feb 14, 2016 1:43 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst and Activation Energy
Replies: 1
Views: 286

Catalyst and Activation Energy

How do catalysts lower the activation energy of a reaction if they are not consumed in the process? If they increase the speed of a reaction and cause more products to be formed, shouldn't they be consumed?
by Ian Hurst 3L
Sun Feb 07, 2016 10:34 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Standard G
Replies: 1
Views: 362

Standard G

I know that delta G= standard G + RTln(Q) and that if the reaction is at standard conditions then delta G goes to 0 but I do not understand why. Can someone explain to me why delta G = 0 when Q=K?
by Ian Hurst 3L
Sun Jan 31, 2016 10:04 pm
Forum: Balancing Redox Reactions
Topic: Work in Electrochemistry
Replies: 1
Views: 254

Re: Work in Electrochemistry

I believe the direction of the electron flow is dependent on how you set up the beakers. Regardless of how you set up the beakers, the solution that will be reduced will be on the "right" and the solution that is oxidized will be on the "left." This is in reference to the equatio...
by Ian Hurst 3L
Mon Jan 25, 2016 8:08 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Giffs Free Energy Definition
Replies: 1
Views: 353

Giffs Free Energy Definition

I understand that Gibbs free energy is a state function (meaning it doesn't matter how you got there) and that if it's positive you know it is describing a spontaneous reaction (meaning the reaction will go forward without external influence). In the course reader it says that this energy is "f...
by Ian Hurst 3L
Sun Jan 17, 2016 5:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies vs. Mean Bond Enthalpy
Replies: 2
Views: 1268

Bond Enthalpies vs. Mean Bond Enthalpy

Can someone explain to me why bonds have an enthalpy and a mean bond enthalpy? (What is the mean bond enthalpy an average of?) Also, which one do we use when solving problems?
by Ian Hurst 3L
Fri Jan 08, 2016 10:47 am
Forum: Phase Changes & Related Calculations
Topic: Heat Capacity and Phase Change
Replies: 2
Views: 310

Heat Capacity and Phase Change

I understand that higher heat capacities lead to lower slopes (and vise versa for lower heat capacities) on heat supplied vs. temperature diagrams because the substance can store more energy. Does the heat capacity of a substance also effect how much energy is needed in a phase change (for example a...
by Ian Hurst 3L
Fri Dec 04, 2015 1:03 am
Forum: *Titrations & Titration Calculations
Topic: Strong Acid Vs Weak Base Titrations
Replies: 1
Views: 375

Strong Acid Vs Weak Base Titrations

I remember in class Professor Lavelle explained that in weak acid- strong base titrations, strong bases "dominate" weak acids. This means that after the equivalence point there should be a higher concentration of OH- ions. How do you know how to set up a reaction (equilibrium) for chemistr...
by Ian Hurst 3L
Sun Nov 29, 2015 10:22 pm
Forum: Lewis Acids & Bases
Topic: Acids and Bases
Replies: 1
Views: 323

Re: Acids and Bases

A polyprotic acid is a compound that can donate more than one proton. Common polyprotic acids are Sulfuric acid (H2SO4) and carbonic acid (H2CO3). You can look at the deprotonation of these compounds as a series of steps. For example, in the first deprotonation, H2CO3 will react with water and form ...
by Ian Hurst 3L
Sun Nov 22, 2015 4:55 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong Vs. Weak Acids
Replies: 1
Views: 337

Strong Vs. Weak Acids

I read that as the strength of acids increases as you go down the halogen group on the periodic table (HF --> HI). Why is it that even though the molecules are becoming less polar (and have a lower difference in electronegativity) they are increasing in acidic strength?
by Ian Hurst 3L
Sat Nov 14, 2015 11:19 pm
Forum: Ideal Gases
Topic: PV=nRT
Replies: 2
Views: 716

Re: PV=nRT

According to the Ideal Gas Law, pressure increases as temperature increases, and temperature increases as volume increases. Then why doesn't it make sense for pressure to increase as volume to increase? Think of the PV= nRT formula like this (for comparing temperature and volume)--> P= (nRT)/V. If y...
by Ian Hurst 3L
Sun Nov 08, 2015 11:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K Constant
Replies: 3
Views: 432

Re: K Constant

K (the equilibrium constant) is derived from the division of products by reactants. (K= [Products]/[Reactants]) A large K (greater than 10^3) means that the reaction favors the formation of products ("equilibrium is shifted to the right"). A small K (less than 10^-3) means that, at equilib...
by Ian Hurst 3L
Sun Nov 01, 2015 10:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distinct DIfference between Linear and Bent
Replies: 2
Views: 5296

Re: Distinct DIfference between Linear and Bent

In determining the shape of a compounds and molecules, I always find it best to draw out and write out the generic formula ( A for the central atom, X for the number of atoms surrounding the central atom, and E for the number of lone pairs on the central atom). Note that bent refers to the AX2E2 and...
by Ian Hurst 3L
Sun Oct 25, 2015 10:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: BF3 VSEPR Shape
Replies: 1
Views: 696

BF3 VSEPR Shape

I have a question regarding the molecular structure of BF3. In the book (page 110) it shows a Boron as the central atom, with 3 Fluorines attached with single bonds. In this structure all of the formal charges are 0, however, the central Boron atom only has 6 electrons and does not satisfy the octet...
by Ian Hurst 3L
Sun Oct 18, 2015 6:38 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Bond Structure
Replies: 1
Views: 315

Ionic Bond Structure

I am confused about the "crystal structure" that forms in ionic bonds. Do all ionic bonds have a crystal structure with cations and anions alternating down a row (Figure 3.5)? And does "lattice energy" only refer to ionic bonds with this structure (or to all crystal structures)?
by Ian Hurst 3L
Sat Oct 10, 2015 1:12 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ionic radius
Replies: 1
Views: 288

Re: Ionic radius

First, lets look at the periodic trends for atomic radius. As you go down the periodic table (from top to bottom), you go from 1s --> 2s -- 3s.. etc... the atomic radius INCREASES (there are more electrons, and each orbital can only hold two electrons, so the more electrons in an element, the bigger...
by Ian Hurst 3L
Sun Oct 04, 2015 3:07 pm
Forum: *Black Body Radiation
Topic: Black body [ENDORSED]
Replies: 3
Views: 722

Re: Black body [ENDORSED]

To understand planck's constant (and his hypothesis), the formula it is used with (E=hv), and its importance, you must first understand that light rays push and pull on an electron. This creates the "wave" picture that is shown by figure 1.7 in the book. How fast the cycles (created by the...

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