Search found 31 matches

by mendozayael_2H
Sun Mar 18, 2018 5:33 am
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Electrolytic cells vs Galvanic Cells
Replies: 3
Views: 573

Electrolytic cells vs Galvanic Cells

What are the most important differences between an electrolytic cell and a galvanic cell (with regards to cell potential)?
by mendozayael_2H
Sun Mar 18, 2018 5:24 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Standard potentials measures in relation to?
Replies: 1
Views: 221

Standard potentials measures in relation to?

The standard potential of an electrode measures the likelihood of a reaction to occur. What is the likelihood tied to?
by mendozayael_2H
Sun Mar 18, 2018 5:10 am
Forum: Student Social/Study Group
Topic: Chemistry Joke
Replies: 57
Views: 2301

Re: Chemistry Joke

According to lecture, what might be Dr. Lavelle's favorite band?

A-ha
by mendozayael_2H
Sun Mar 18, 2018 5:05 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity in a cell reaction
Replies: 4
Views: 292

Spontaneity in a cell reaction

What can the relation between Ecell and delta G tell me about whether a cell reaction is spontaneous?
by mendozayael_2H
Sun Mar 18, 2018 3:44 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Phase changes and entropy
Replies: 5
Views: 350

Phase changes and entropy

When we calculate phase changes, why is q in S = q/T replaced with the enthalpy H of the phase change? Is it just easier or a connection between q and H
by mendozayael_2H
Sun Mar 18, 2018 1:13 am
Forum: Phase Changes & Related Calculations
Topic: Energy from constant pressure versus constant volume RXN
Replies: 2
Views: 212

Energy from constant pressure versus constant volume RXN

Does more energy come from a reaction at constant pressure or at constant volume? Does it have to do with work?
by mendozayael_2H
Wed Mar 07, 2018 10:38 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Rate Law being affected by product [ENDORSED]
Replies: 2
Views: 213

Rate Law being affected by product [ENDORSED]

When should the concentration of the product be considered when determining the rate law of a reaction? Or does this have something to do with whether you want just the forward or reverse reaction? This came up with overall orders in ch15.3
by mendozayael_2H
Wed Mar 07, 2018 10:24 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Coefficients and change of molar concentration
Replies: 1
Views: 129

Coefficients and change of molar concentration

If the concentration of a molecule [A] is doubled, does the coefficient of the molecule reflect this change of concentration? So would a[A] then be 2[A]?
by mendozayael_2H
Tue Feb 13, 2018 6:18 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Constant Volume and work
Replies: 1
Views: 114

Constant Volume and work

Is it possible for work to occur under constant volume for enthalpy? Not sure if this question makes sense, might be asking an irrelevant question.
by mendozayael_2H
Tue Feb 13, 2018 5:49 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: ∆U equation
Replies: 2
Views: 120

Re: ∆U equation

Don't think it'll be on the midterm but I think the 3/2R could be the value for constant volume for the work done in the system. In that case, q would have to equal 0.
by mendozayael_2H
Tue Feb 13, 2018 4:48 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: enthalpy of surroundings
Replies: 1
Views: 85

enthalpy of surroundings

When does enthalpy S of the surroundings equal to 0? I think there has to be more info given, I'm just not sure. Thinking in terms of Stotal= Ssurroundings + Ssystem.
by mendozayael_2H
Wed Jan 31, 2018 11:51 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: what exactly is free energy?
Replies: 5
Views: 210

Re: what exactly is free energy?

Gibbs free energy is the energy in a process that can be used to do work in the system. It can tell whether the enthalpy, temperature, and entropy (properties of a reaction) are favorable for a reaction to occur. Remember ΔG = ΔH - TΔS, (change in enthalpy - temperature * change in entropy).
by mendozayael_2H
Wed Jan 31, 2018 11:30 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: entropy and heat capacity
Replies: 2
Views: 107

Re: entropy and heat capacity

I believe they are the same when working with ideal gases or something because we assume the heat capacity is not affected by the temperature. Someone fact check me?
by mendozayael_2H
Sun Dec 10, 2017 1:41 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Delocalized Electrons
Replies: 3
Views: 360

Re: Delocalized Electrons

I believe they have similar or the same meaning. Delocalized meaning the electrons do not have one place they must be for the atom to be most stable. Resonance means multiple bonds (and thereby the electrons/orbitals)of an atom have the same function/connection if found in a different, but equal loc...
by mendozayael_2H
Sun Dec 10, 2017 1:18 am
Forum: Trends in The Periodic Table
Topic: Electron shielding
Replies: 2
Views: 212

Re: Electron shielding

Electron shielding causes the nucleus of an atom to have a weaker pull of valence electrons. Electrons in the inner shells fulfill the opposite charge requirement of the nucleus (which is positive) for the atom to be stable, so the nucleus doesn't have as strong an attractive pull on electrons farth...
by mendozayael_2H
Sun Dec 03, 2017 11:01 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak Acids / Strong Acids
Replies: 5
Views: 260

Re: Weak Acids / Strong Acids

Strong acids will usually be at or close to 100% complete ionization and can donate more protons than a weak one because the strong acids lose more hydrogen atoms. Bases are similar in that strong bases will disassociate (will ionize) better than weak ones. pH will tell you where the acid/base stand...
by mendozayael_2H
Sun Dec 03, 2017 10:48 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation States
Replies: 4
Views: 205

Re: Oxidation States

To determine the oxidation state of a metal in a complex ion, use this formula: Oxidation # = Charge of ion - [(number (amount) of ligand) X (charge of ligand)]. If you have multiple ligands, do the bracketed values once for each ligand.
by mendozayael_2H
Sun Nov 26, 2017 11:46 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 11.37
Replies: 3
Views: 185

Re: 11.37

Basically, whatever you do to one side you must do to the other. In a) the reactant and product are flipped, so when plugging into the Kc equation, the answer is flipped, so you get 1/K. For b) since the exponents of the reactants are being square-rooted when solving because they have fractions for ...
by mendozayael_2H
Sun Nov 26, 2017 11:22 pm
Forum: Naming
Topic: 17.5
Replies: 1
Views: 132

Re: 17.5

Not sure where the question came from but just follow the procedures from the mentioned Toolbox for naming and writing a formula. Ex. : [FeCl(OH2)5]+ is written as such because you start with the central atom (Fe), then add the symbols for the ligands in alphabetical order, unless emphasis needed on...
by mendozayael_2H
Sun Nov 19, 2017 10:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Predicting bond angles
Replies: 4
Views: 206

Re: Predicting bond angles

The simplest trick is knowing how many bonding areas are on a given molecule. If you don't know it, then Lewis structure is your next bet, from which you can figure geometric shape and thus bond angles. Familiarity with elements' bond patterns helps
by mendozayael_2H
Sun Nov 19, 2017 10:29 pm
Forum: Hybridization
Topic: Purpose of hybridization [ENDORSED]
Replies: 5
Views: 640

Re: Purpose of hybridization [ENDORSED]

The reason we use hybridization is in part to find the lowest energy (and thereby more stable) form of a molecule. Hybridization differs from VSEPR model because the latter can only help find geometric shapes of molecules while the former can build on VSEPR models to figure how many sigma- and pi- b...
by mendozayael_2H
Sun Nov 05, 2017 6:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electrostatic Potential Energy
Replies: 1
Views: 102

Electrostatic Potential Energy

I was wondering if electrostatic potential energy relative to (q1)(q2)/r had an importance besides proving that outer electrons have a nuclear charge.
by mendozayael_2H
Sat Nov 04, 2017 2:51 pm
Forum: Dipole Moments
Topic: Bond length [ENDORSED]
Replies: 4
Views: 275

Bond length [ENDORSED]

For the formula to measure Dipole moments, what is the bond length (is it the distance between nuclei)? Does it change depending on whether it is a single, double, or triple bond?
by mendozayael_2H
Sun Oct 29, 2017 11:30 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Periodic Table differences
Replies: 3
Views: 197

Re: Periodic Table differences

I believe the difference in the Tables is that the one with La and Ac on the bottom (the book's version) is showing that the two elements are actually a part of the lanthanide and actinide periods, not separate from them. However, this version may cause confusion and misinterpretation of the electro...
by mendozayael_2H
Sun Oct 29, 2017 11:12 pm
Forum: Lewis Structures
Topic: Lewis Dot Diagrams [ENDORSED]
Replies: 2
Views: 108

Re: Lewis Dot Diagrams [ENDORSED]

Nope. It's helpful to start on sides that are farthest to other elements so you can draw bonds between them.
by mendozayael_2H
Sun Oct 22, 2017 10:48 pm
Forum: DeBroglie Equation
Topic: Momentum [ENDORSED]
Replies: 3
Views: 236

Re: Momentum [ENDORSED]

The mass variable (m) will change according to what particle/object is given. I'd say typically the particle will be an electron, who's mass is 9.1093 x 10^(-31) kg, so you can use that. But the question should let you know what particle is being observed, and you would use that particle's mass for ...
by mendozayael_2H
Sun Oct 22, 2017 10:37 pm
Forum: Photoelectric Effect
Topic: Exam Question Clarification [ENDORSED]
Replies: 3
Views: 227

Exam Question Clarification [ENDORSED]

One of the concept questions asked whether increasing the intensity of light waves would make able to eject an electron. Just wanted to clarify if "increasing the intensity" meant increasing the amount of the same-sized light waves hitting the surface, or if it meant increasing its frequen...
by mendozayael_2H
Sun Oct 15, 2017 11:57 am
Forum: Properties of Light
Topic: 1.9
Replies: 2
Views: 147

Re: 1.9

Using the frequencies is another way to match the events to the data. Lower frequencies means it will be a weaker type of radiation (such as microwave radiation) and higher frequencies are the stronger kinds of radiation ( like x-rays). Hope this helps
by mendozayael_2H
Sun Oct 15, 2017 11:53 am
Forum: Properties of Light
Topic: 1.9
Replies: 2
Views: 147

Re: 1.9

One way to do it is ordering the size of wavelengths you found from least to greatest and then matching it to the wavelengths of each type of radiation given. Fig.1.9 on page 6 might help you do this part.
by mendozayael_2H
Mon Oct 09, 2017 12:11 am
Forum: Photoelectric Effect
Topic: CH.1 #33 pt B
Replies: 3
Views: 268

CH.1 #33 pt B

#1.33 says: "The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 X 10^3 km/s. (a) What is the wavelength of the ejected electron? (b) No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50 X 10^16 Hz. How much ...
by mendozayael_2H
Tue Oct 03, 2017 5:44 pm
Forum: Balancing Chemical Reactions
Topic: Help on HW question H1
Replies: 5
Views: 268

Re: Help on HW question H1

I believe that procedure is not allowed because adding an Oxygen atom to the CuO molecule would destabilize it, whereas adding coefficients changes the number of molecules rather than their structure.

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