Search found 39 matches

by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:56 am
Forum: General Rate Laws
Topic: Unimolecular
Replies: 5
Views: 358

Re: Unimolecular

Unimolecular reactions are reactions where one molecule of reactant reacts to form any amount of product. For example, the decomposition of a single molecule is a unimolecular reaction.

Bimolecular reactions are reactions where two molecules of reactants react to form any amount of product.
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:54 am
Forum: General Rate Laws
Topic: number of mols effect on result
Replies: 2
Views: 250

Re: number of mols effect on result

The number of moles of reactants and products may affect the rate of the reaction. The magnitude of the change depends on the specific reactant's or product's being zero, first, or second order.
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:48 am
Forum: General Rate Laws
Topic: Rate Law
Replies: 6
Views: 480

Re: Rate Law

Neither catalysts nor intermediates go into the rate law.

Though it does affect the rate at which the reaction proceeds, since a catalyst doesn't count as a reactant or product, it doesn't count in the rate law.
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:43 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 2
Views: 208

Galvanic Cells

Are Galvanic cells the samosa voltaic cells? If not, what are their differences?
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:35 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reducing power
Replies: 2
Views: 1815

Re: Reducing power

Reducing power is the strength of a chemical's ability to reduce another substance. It's the ability to gain electrons.

Oxidizing power is the strength of a chemical's ability to oxidize another substance. It's how easily the chemical donates/loses electrons.
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:30 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity in a cell reaction
Replies: 4
Views: 297

Re: Spontaneity in a cell reaction

However, if you didn't know either delta G or Ecell, then you can use the equation
to find tif you know the other one.
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 5:25 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity in a cell reaction
Replies: 4
Views: 297

Re: Spontaneity in a cell reaction

I'm pretty sure delta G alone can tell you if the reaction is spontaneous. If delta G is positive, then the reaction is non-spontaneous. If delta G is negative, then the reaction is spontaneous.

I'm not sure if I answered what you were looking for, but I hope this helps!
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 1:18 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: calculating n
Replies: 9
Views: 421

Re: calculating n

You proceed through the redox reaction as normal and then count the number of electrons. Remember to multiply the half-reactions beforehand, so the moles of electrons are equal to each other. The number of electrons, then, is "n".
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 1:10 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Value of n
Replies: 3
Views: 207

Re: Value of n

The "n" in the Nernst equation is the number of electrons transferred in the reaction
by Matt_Fontila_2L_Chem14B
Sun Mar 18, 2018 1:05 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Strength of Oxidation/Reducing Agents
Replies: 2
Views: 233

Re: Strength of Oxidation/Reducing Agents

One of the things that help me remember the strength of oxidizing and reducing agents is: The greater (more positive) the standard reduction potential, the stronger the substance is as an oxidizing agent. The lower (more negative) the standard reduction potential, the stronger the substance is as a ...
by Matt_Fontila_2L_Chem14B
Sat Mar 17, 2018 6:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Functions
Replies: 4
Views: 308

Re: State Functions

State functions are those that depend only on its initial and final states. They don't depend on the path taken to get to the final state.
by Matt_Fontila_2L_Chem14B
Sat Mar 17, 2018 5:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.73a - Resonance of Benzene
Replies: 2
Views: 202

Re: 8.73a - Resonance of Benzene

I believe the most commonly used resonance structure of benzene is the one with 3 single and 3 double bonds. I'd just use that one.
by Matt_Fontila_2L_Chem14B
Sat Mar 17, 2018 5:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of RXN using standard enthalpy of formation
Replies: 2
Views: 217

Re: Enthalpy of RXN using standard enthalpy of formation

No, you don't have to change the signs when plugging the values into the enthalpy of reaction equation. Just make sure that the sum of the enthalpies for the products is subtracted by the sum of the enthalpies of reactants.
by Matt_Fontila_2L_Chem14B
Fri Jan 19, 2018 4:11 am
Forum: Phase Changes & Related Calculations
Topic: Heat Capacity
Replies: 6
Views: 273

Re: Heat Capacity

More often than not, our final answers are in kilojoules. The only times I can think of using joules were when we calculated using specific heat capacity as stated above.

I usually leave my answers in kilojoules unless stated otherwise.
by Matt_Fontila_2L_Chem14B
Thu Jan 18, 2018 7:43 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Substituting -P*DeltaV into the DeltaU Equation [ENDORSED]
Replies: 1
Views: 110

Substituting -P*DeltaV into the DeltaU Equation [ENDORSED]

When q = qp, the equation for the First Law of Thermodynamics is DeltaU = DeltaH - P*DeltaV.

Can we only substitute -P*DeltaV for work when q = qp (DeltaH) or can we always replace w with - P*DeltaV ?
by Matt_Fontila_2L_Chem14B
Thu Jan 18, 2018 5:46 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Is there a way specific way to approach into seeing if open closed or isolated?
Replies: 9
Views: 339

Re: Is there a way specific way to approach into seeing if open closed or isolated?

First, determine what the system and its surroundings are. Then figure out whether mass and energy can be transferred from the system to its surroundings and vice versa.
by Matt_Fontila_2L_Chem14B
Wed Jan 10, 2018 3:18 pm
Forum: Phase Changes & Related Calculations
Topic: State Properties: q vs. qp
Replies: 3
Views: 190

State Properties: q vs. qp

I'm confused why q is not a state property while qp (heat at constant pressure) is a state property. I know that they are heat and enthalpy, but how do the "paths taken" to get to their final states matter for each?
by Matt_Fontila_2L_Chem14B
Wed Jan 10, 2018 3:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 5
Views: 209

Re: Bond Enthalpies

The reactants' bonds are broken so new bonds in the products can be made. Energy is required for a bond to be broken (endothermic), that's why the enthalpies of the reactant's broken bonds are positive. When bonds are formed, energy is released (exothermic), that's why the enthalpies of the product'...
by Matt_Fontila_2L_Chem14B
Wed Jan 10, 2018 3:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Change in Enthalpy of the Reverse Reaction
Replies: 5
Views: 213

Change in Enthalpy of the Reverse Reaction

I remember in class today, Dr. Lavelle was calculating reaction enthalpies with us and he said something along the lines of the changes in enthalpies of the reverses of vaporization (condensation), melting (freezing), etc. were negative or inversely proportional or some other simple change from the ...
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 5:10 pm
Forum: Naming
Topic: Names of Polydentates
Replies: 2
Views: 159

Names of Polydentates

Can you figure out what kind of polydentate a compound is from the name alone? What makes it a monodentate, bidentate, tridentate, etc.?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 5:07 pm
Forum: Sigma & Pi Bonds
Topic: Delocalization in carbon rings
Replies: 1
Views: 138

Delocalization in carbon rings

What is delocalization of bonds and why does it happen in carbon rings like benzene?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 5:02 pm
Forum: Ideal Gases
Topic: Changes in Pressure
Replies: 1
Views: 218

Changes in Pressure

Why do some changes in pressure affect the concentrations at equilibrium and others don't? I believe that in class, we went over changes in pressure through volume and adding other gases. Why does one work and not the other?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:58 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Calculating the initial concentration without x
Replies: 1
Views: 104

Calculating the initial concentration without x

Today in lecture, Dr Lavelle covered ICE boxes in which we were able to calculate an initial concentration, given the final concentration, without using x in the change part of the ICE Box. How did he calculate the equilibrium molar concentration without x?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:50 pm
Forum: Identifying Acidic & Basic Salts
Topic: Neutralization
Replies: 1
Views: 219

Neutralization

Neutralization is a reaction with acids and bases that produce a salt and water. Does that mean neutralization can only happen with strong acids and bases where every reactant has been dissociated/deprotonated?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Percentage Deprotonation
Replies: 4
Views: 798

Re: Percentage Deprotonation

If you were looking at it from an ICE Box point of view, the percentage deprotonation would be the final concentration of H+ (usually x) divided by the initial concentration of the acid.
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:41 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka and Kb when temp. changes [ENDORSED]
Replies: 1
Views: 213

Ka and Kb when temp. changes [ENDORSED]

I know that the product of Ka and Kb is Kw, and that Kw changes when the temperature changes. Does the change in temperature affect Ka and Kb equally? Do they both increase or decrease at the same ratio?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:37 pm
Forum: Conjugate Acids & Bases
Topic: Oxoacids
Replies: 5
Views: 334

Re: Oxoacids

*stabilized by an electron
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:36 pm
Forum: Conjugate Acids & Bases
Topic: Oxoacids
Replies: 5
Views: 334

Oxoacids

When Dr. Lavelle was explaining Relative Acidity, he mentioned that oxoacids more readily lose a hydrogen ion if the resulting anion is stabilized bean electron.

What is an oxoacid and what properties make it so different from other acids?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 5% Rule
Replies: 1
Views: 124

5% Rule

What is the 5% rule and how do you use it in relation to ICE Boxes? Is there an equation for it?
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:24 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 25 degrees C
Replies: 2
Views: 140

Re: 25 degrees C

If the temperature at which the reaction occurs is not at 25 degrees C, the Ka (the acidity constant) changes. Temperature is one of the few things that change the Ka.
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:22 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Reason for not including water
Replies: 6
Views: 304

Re: Reason for not including water

Water is the solvent in which the reaction occurs. It's not included in the K expression.
by Matt_Fontila_2L_Chem14B
Fri Dec 08, 2017 4:19 pm
Forum: *Titrations & Titration Calculations
Topic: ICE Box: How to find the equation to plug into the Quadratic Formula
Replies: 2
Views: 449

ICE Box: How to find the equation to plug into the Quadratic Formula

How does one find the equation (a,b, and c) to plug into the Quadratic Formula from the ICE Box? My TA gave us the problem: C6H5COOH <---> H+ + C6H5COO- , the Ka = 6.28*10^-5, and the initial concentration for C6H5COOH = 0.0237 I filled in the ICE box and got to Ka=(x^2)/(0.0237-x)=6.28*10^-5 but th...
by Matt_Fontila_2L_Chem14B
Fri Oct 27, 2017 4:29 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron-electron Repulsion
Replies: 1
Views: 1691

Electron-electron Repulsion

I'm having trouble understanding the concept of electron-electron repulsion. I know that electron-electron repulsion increases as one moves down a column of the periodic table. If elements in the same column have nearly the same electron configuration, what is the difference that causes the change i...
by Matt_Fontila_2L_Chem14B
Fri Oct 27, 2017 4:23 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: electron spin quantum number (ms) [ENDORSED]
Replies: 4
Views: 305

Re: electron spin quantum number (ms) [ENDORSED]

The electron spin quantum number is the direction in which an electron in an orbital spins. There can only be two paired electrons. One of the electrons spins in one direction; we give that the electron spin quantum number +1/2. The other paired electron spins in the opposite direction; we give that...
by Matt_Fontila_2L_Chem14B
Fri Oct 20, 2017 4:52 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum Numbers [ENDORSED]
Replies: 6
Views: 429

Re: Magnetic Quantum Numbers [ENDORSED]

If, however, you were talking about the Spin Magnetic Quantum Number, the positive or negative in front of the 1/2 is the most important part in determining which way the electron is spinning.
by Matt_Fontila_2L_Chem14B
Fri Oct 20, 2017 4:39 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 7
Views: 373

Re: Rydberg Equation

I've tried using both. The formula with frequency worked more like a one step problem for me. I personally like using the shorter -hR/n^2 equation twice and taking the difference between the initial and final energies, because it feels like a step by step process. In the end, it's up to your prefere...
by Matt_Fontila_2L_Chem14B
Fri Oct 13, 2017 4:56 pm
Forum: Properties of Light
Topic: Exited state
Replies: 5
Views: 334

Re: Exited state

To jump to another level, for example from n=1 to n=2, the excited electron has to be hit with enough energy to cross that threshold, right? Am I correct in believing that it won't jump into its excited state if it wasn't hit with enough energy?
by Matt_Fontila_2L_Chem14B
Fri Oct 13, 2017 4:44 pm
Forum: Properties of Light
Topic: Velocity [ENDORSED]
Replies: 13
Views: 709

Re: Velocity [ENDORSED]

If we can use them interchangeably for this class, does that mean we can use the speed of light in a vacuum (2.988x10^8 m/s) in De Broglie's Equation?

λ = h/m*v

Would we then just need the mass to determine the wavelength?
by Matt_Fontila_2L_Chem14B
Wed Oct 04, 2017 4:31 pm
Forum: Limiting Reactant Calculations
Topic: Extensive vs. Intensive properties
Replies: 2
Views: 236

Re: Extensive vs. Intensive properties

An extensive property is a characteristic dependent on the amount of material present. Volume, weight, and mass are examples of extensive properties. An intensive property is independent of all outside influences. An intensive property does not change depending on the amount of material present. Den...

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