Search found 19 matches

by Matthew Gutierrez 2D
Mon Feb 29, 2016 10:32 pm
Forum: *Alkanes
Topic: Self-Test 4.1A
Replies: 1
Views: 259

Re: Self-Test 4.1A

An alkyl carbanion has the structural formula of an alkyl group, like CH3, where the carbon is negatively charged. An aryl carbanion has the structural formula of an aryl group, which I think is ring shaped. You can see this on page 146 in the organic chemistry book. However, this will not be on Qui...
by Matthew Gutierrez 2D
Thu Feb 18, 2016 11:36 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Forward rate=Reverse rate
Replies: 2
Views: 795

Re: Forward rate=Reverse rate

I am not sure if I'm understanding your question correctly. At equilibrium, there is no net change in the concentrations of the reactants and products because the forward and reverse reaction rates are equal. Equilibrium could also favor a larger concentration of reactants. Please correct me if I am...
by Matthew Gutierrez 2D
Wed Feb 03, 2016 10:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to determine most strongly reducing metal
Replies: 1
Views: 296

How to determine most strongly reducing metal

When given two metals like Fe and Cu, how do we determine which one is more strongly reducing using the electrochemical series? Looking at the table, there are multiple standard reduction potentials for Fe and Cu depending on which ion is reduced. How do we know which standard reduction potentials t...
by Matthew Gutierrez 2D
Thu Jan 28, 2016 10:47 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Understanding standard potentials of redox couples
Replies: 1
Views: 617

Understanding standard potentials of redox couples

In page 582 of the textbook, it states that "the more negative the standard potential of a couple, the greater its reducing strength." I thought that a negative standard potential meant that the anode was less likely to be oxidized. I am a bit confused after reading this. Here is what I un...
by Matthew Gutierrez 2D
Thu Jan 28, 2016 10:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Potential Difference Between Electrodes
Replies: 1
Views: 445

Re: Potential Difference Between Electrodes

I stands for current. So as the current drawn approaches 0, the potential difference between the two electrodes becomes its maximum potential. By definition, this is called the electromotive force.
by Matthew Gutierrez 2D
Sat Jan 23, 2016 1:05 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: delta S
Replies: 4
Views: 635

Re: delta S

Yes, the change in entropy is greater at lower temperatures than higher temperatures.
by Matthew Gutierrez 2D
Thu Jan 14, 2016 9:11 pm
Forum: Calculating Work of Expansion
Topic: solving for work
Replies: 2
Views: 494

Re: solving for work

Yes, because you want the units to cancel out so that you are left with joules.
by Matthew Gutierrez 2D
Thu Jan 14, 2016 9:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 2
Views: 682

Re: Bond Enthalpy

You make the bond enthalpy negative when you are forming a bond. It is negative because forming a bond is exothermic because the molecule becomes more stable and releases energy.
by Matthew Gutierrez 2D
Sat Jan 09, 2016 1:47 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: First Law vs Conservation of Mass
Replies: 1
Views: 380

Re: First Law vs Conservation of Mass

The Law of Conservation of Mass, in the context of a chemical reaction, states that no atoms are created or destroyed in a reaction. So the number of atoms of reactants is equal to the number of atoms of products. This is why we balance chemical equations. Generally, it relates to matter and how it ...
by Matthew Gutierrez 2D
Sat Jan 09, 2016 1:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Volume vs. Constant Pressure in a Calorimeter
Replies: 2
Views: 1582

Constant Volume vs. Constant Pressure in a Calorimeter

I am still confused why at constant volume, the heat transfer is called "deltaU", while in a constant pressure environment, it is called "deltaH". How do the difference in conditions change what value is being measured and why?
by Matthew Gutierrez 2D
Mon Nov 16, 2015 7:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Video: Applying Le Chatelier's Principle to Photosyntheisis
Replies: 3
Views: 3375

Video: Applying Le Chatelier's Principle to Photosyntheisis

Chem 14A Problem 11.115.mp4 [ 108.67 MiB | Viewed 3375 times ]

This video details the reasoning for problem 11.115.
by Matthew Gutierrez 2D
Fri Oct 30, 2015 12:30 am
Forum: NEWS & RESOURCES
Topic: MO Diagrams for Heteronuclear Molecules
Replies: 2
Views: 1909

MO Diagrams for Heteronuclear Molecules

I am confused on why the textbook lists the order of MOs as: (1sigma)(2sigma*)(1pi)(3sigma)(2pi*)(4sigma*) I thought that when given a heteronuclear molecule like CO, we would arrange electrons into the MOs like: (sigma2s)(sigma2s*)(pi2p)(sigma2p)...etc. Which way is correct? And how would I know wh...
by Matthew Gutierrez 2D
Sat Oct 17, 2015 7:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing electron configurations for ions with d-orbitals
Replies: 1
Views: 391

Writing electron configurations for ions with d-orbitals

I have been having trouble with this lately. When writing the electron configuration for an ion like Sn^4+, do we remove the 4 electrons from the 4d orbital or the 5s and 5p orbitals? I wrote the configuration as [Kr]4d^10, removing the 4 electrons from the 5s^2 and 5p^2. It does not feel right beca...
by Matthew Gutierrez 2D
Sun Oct 11, 2015 10:40 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals vs. subshells; Quantum numbers
Replies: 1
Views: 400

Re: Orbitals vs. subshells; Quantum numbers

Think of a set of the numbers as an address. For example you could look at a set of quantum numbers (n,l,ml,ms) as (country, housing complex, room, 1/2 or -1/2). It's not a literal analogy, but it helps. n= energy level and size (1,2,3,etc.) Within each energy level there are: l= shape of the orbita...
by Matthew Gutierrez 2D
Sun Oct 11, 2015 10:23 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Hydrogen Atom / Quantum Level
Replies: 1
Views: 346

Re: Hydrogen Atom / Quantum Level

You can use the equation En=\frac{-hR}{n^{2}} . Change in energy for the electron " \Delta E " = E 4 -E n . In other words, energy of electron at n=4 minus energy of electron at initial state n. So, solve the equation for E n , which represents the energy of the electron at its initial qua...
by Matthew Gutierrez 2D
Sun Oct 11, 2015 10:13 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Problem 1.34
Replies: 1
Views: 372

Re: Problem 1.34

The equation for finding the kinetic energy of an ejected electron is: \frac{1}{2}mv^{2}=hv-\phi (pg. 13) Because the question is asking for the maximum energy of a photon needed, without ionizing the atom, you can set the left side of the equation equal to 0 because you do not want the electron eje...
by Matthew Gutierrez 2D
Sun Oct 11, 2015 10:00 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Constant
Replies: 2
Views: 609

Re: Rydberg Constant

What value did they get for the Rydberg constant in that class?
by Matthew Gutierrez 2D
Sun Oct 11, 2015 9:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrons Moving in Orbitals
Replies: 1
Views: 363

Electrons Moving in Orbitals

I'm having a bit of trouble visualizing this concept. I don't know if I have the right idea, but this is how I see it so far. When an electron moves from, let's say, a 2s orbital to a 2p orbital, does the electron actually move in a pattern consistent with the p-orbital dumbbell shape? In other word...
by Matthew Gutierrez 2D
Fri Oct 02, 2015 11:49 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: h/4pi in Heisenberg's Indeterminacy Equation
Replies: 3
Views: 2106

h/4pi in Heisenberg's Indeterminacy Equation

What does the in the equation represent and why does it have to be less than or equal to the product of ? Was this value arbitrarily chosen for the inequality or was it actually experimentally determined?

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