Search found 29 matches

by Salma Quintanilla 1J
Sun Mar 11, 2018 3:03 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reversible/irreversible
Replies: 2
Views: 148

Re: reversible/irreversible

The difference is that during a reversible process, the system will always be at equilibrium with its surroundings. For an irreversible process, there will always be an entropy change.
by Salma Quintanilla 1J
Sun Mar 11, 2018 1:55 am
Forum: General Rate Laws
Topic: graphs
Replies: 8
Views: 379

Re: graphs

I would know them just in case, especially since Dr. Lavelle did go over them during lecture. In the textbook, these graphs are found on page 631 in Chapter 15.6.
by Salma Quintanilla 1J
Sun Mar 11, 2018 1:53 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: units
Replies: 4
Views: 408

Re: units

I'm pretty sure that we will only have to use SI units, therefore, only mol, L, and s. But then again, I am not 100% sure.
by Salma Quintanilla 1J
Thu Mar 01, 2018 9:18 pm
Forum: General Rate Laws
Topic: Rate Law dependent on Reactants [ENDORSED]
Replies: 4
Views: 285

Re: Rate Law dependent on Reactants [ENDORSED]

The rate constant (k) depends on the temperate and activation energy.
by Salma Quintanilla 1J
Thu Mar 01, 2018 9:16 pm
Forum: Second Order Reactions
Topic: The graph of second order [ENDORSED]
Replies: 5
Views: 372

Re: The graph of second order [ENDORSED]

For the graph of the second order reaction:
1/[A] concentrations increase over time and [A] concentrations decrease over time.
If you were to graph this, you would end up getting a positive slope, since the y-axis of the graph is 1/[A].

Hope this made sense!
by Salma Quintanilla 1J
Thu Mar 01, 2018 9:12 pm
Forum: General Rate Laws
Topic: Reactions higher than the second order [ENDORSED]
Replies: 3
Views: 197

Re: Reactions higher than the second order [ENDORSED]

Will we be talking about negative order, mixed order, or fractional order?
by Salma Quintanilla 1J
Sun Feb 18, 2018 11:28 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation (log vs. ln)
Replies: 5
Views: 1671

Re: Nernst Equation (log vs. ln)

I believe that you should use the log or ln stated for each version of the equation given just to avoid an error but to be truthful I'm not entirely sure if there is a difference.
by Salma Quintanilla 1J
Sun Feb 18, 2018 11:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: About the standard cell potentials for aqueous solutions
Replies: 2
Views: 138

Re: About the standard cell potentials for aqueous solutions

I'm not completely sure what you mean by "which equation to use?" Maybe like Cassidy said, it would be best to provide a specific example.
by Salma Quintanilla 1J
Sun Feb 18, 2018 11:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 4
Views: 165

Re: Salt Bridge

A salt bridge is an inverted U-tube that contains an electrolyte and it connects the two half-cells in a galvanic cell. The importance of the salt bridge is to maintain electrical neutrality.
by Salma Quintanilla 1J
Mon Jan 29, 2018 6:57 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy: State Function? [ENDORSED]
Replies: 4
Views: 624

Re: Gibbs Free Energy: State Function? [ENDORSED]

The Gibbs energy is defined solely in terms of state functions, and so G is a state function. The temperature and pressure are constant, and with that we can already predict using Gibbs free energy the spontaneity of a process sole in terms of the properties of a system.
by Salma Quintanilla 1J
Mon Jan 29, 2018 6:50 pm
Forum: Administrative Questions and Class Announcements
Topic: homework/reading schedule
Replies: 3
Views: 267

Re: homework/reading schedule

If you go onto the class website for Chem 14b, there are a few outlines for what we should be learning from each chapter and also what homework problems we should do. Since we are still reviewing the first law and the second law of thermodynamics in lectures, I would do homework problems from both c...
by Salma Quintanilla 1J
Mon Jan 29, 2018 6:48 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs Irreversible
Replies: 4
Views: 250

Re: Reversible vs Irreversible

Reversible expansion is one that can be reversed by an infinitely small change in a variable. An example of this at work would be when a gas expands reversibly, the pressure on the outside is matched to the pressure of the gas during the expansion. This example could be directed in either direction,...
by Salma Quintanilla 1J
Fri Jan 26, 2018 8:57 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy of gas vs liquid vs solid
Replies: 7
Views: 2542

Re: Entropy of gas vs liquid vs solid

Liquids have more energy and entropy than solids. When there is an increased number of gas molecules, there is also an increase in entropy.
by Salma Quintanilla 1J
Fri Jan 26, 2018 8:44 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Relation of degeneracy and entropy
Replies: 2
Views: 170

Re: Relation of degeneracy and entropy

The number of possible states for a system of given energy is called the degeneracy and it is denoted by g in the equation S=k ln (g). So when there is an increase in the degeneracy the energy level is higher versus when the degeneracy decreases, the energy level is lower.
by Salma Quintanilla 1J
Tue Jan 23, 2018 7:44 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Calculations (9.1)
Replies: 5
Views: 1970

Re: Entropy Calculations (9.1)

In this case, the q would be negative because the enthalpy (the amount of heat released or absorbed at a constant pressure) in this question is being released. The enthalpy value is equivalent to q= delta H and if the reaction is exothermic (which it is in this question because it is giving off heat...
by Salma Quintanilla 1J
Thu Nov 30, 2017 7:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Denate
Replies: 3
Views: 236

Re: Denate

And the common polydentates include:
1)Bidentate: C2O4^2- and ethylenediamine (H2NCH2CH2NH2)
2) Tridentate: Diethylenetriamine
3) Hexadentate: edta
by Salma Quintanilla 1J
Thu Nov 30, 2017 7:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Denate
Replies: 3
Views: 236

Re: Denate

Common monodentates include: H20, CN-, SCN-, X-, NH3, NO2-, OH-.
by Salma Quintanilla 1J
Thu Nov 30, 2017 7:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Equilibrium
Replies: 3
Views: 633

Re: Calculating Equilibrium

Remember that the equilibrium constant Kc is defined as Kc= [C]^c[D]^d/[A]^a[B]^b
by Salma Quintanilla 1J
Wed Nov 15, 2017 3:19 pm
Forum: Hybridization
Topic: Diapole
Replies: 4
Views: 335

Re: Diapole

In the example of water, (H2o) there are two dipole moments, a partial positive with both hydrogen atoms and a partial negative dipole over the Oxygen atom. This configuration overall is considered non-polar even know there is a dipole moment.
by Salma Quintanilla 1J
Wed Nov 15, 2017 3:07 pm
Forum: Hybridization
Topic: Notation
Replies: 6
Views: 387

Re: Notation

I think that the only time we have write out this fully is when we are asked to write out the full and complete (extended) electron configuration rather than just the ground state electron.
by Salma Quintanilla 1J
Wed Nov 08, 2017 12:37 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3.5 b) [ENDORSED]
Replies: 5
Views: 361

Re: 3.5 b) [ENDORSED]

If that is what is easiest for you. Just remember that in the answer, the n number should be in increasing order of energy levels. By doing this, it will be easier to write out the electron configurations for cations and anions.
by Salma Quintanilla 1J
Wed Nov 08, 2017 12:34 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: The valence electron of Cu and Br
Replies: 2
Views: 607

Re: The valence electron of Cu and Br

The easiest way for me to count valence electrons is to count the group numbers instead of the period numbers.
by Salma Quintanilla 1J
Wed Nov 08, 2017 12:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Midterm
Replies: 2
Views: 256

Re: Midterm

I do not think that we have to know the VSEPR formulas or shapes for this midterm because that is mainly in chapter 4 and the midterm will cover the fundamentals and chapters 1-3.
by Salma Quintanilla 1J
Wed Nov 08, 2017 12:30 am
Forum: Lewis Structures
Topic: Where to place lone pairs
Replies: 2
Views: 197

Re: Where to place lone pairs

If the lewis dot structure happens to be a square planar shape, you can place one pair of lone pairs on either ends of the central atom (top and bottom) but if the VSEPR shape is for instance T-shaped, then you can place the pairs of lone pairs both on the top of the central atom but as far away fro...
by Salma Quintanilla 1J
Wed Nov 08, 2017 12:26 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Central Atom
Replies: 4
Views: 320

Re: Central Atom

The least electronegative element tends to be the central atom when creating the lewis dot structures because they tend to be more stable this way. However, there is an exception with H2O because oxygen is more electronegative than hydrogen but in this case, oxygen is still the central atom.
by Salma Quintanilla 1J
Tue Oct 31, 2017 9:15 pm
Forum: Octet Exceptions
Topic: Octets
Replies: 8
Views: 602

Re: Octets

What is a resonance hybrid?
by Salma Quintanilla 1J
Tue Oct 31, 2017 7:41 pm
Forum: Electronegativity
Topic: Electronegativity [ENDORSED]
Replies: 5
Views: 407

Re: Electronegativity [ENDORSED]

Fluorine on the periodic table is the first element in that group and it is pretty far to the right so it does still follow the electronegativity trend of increasing across the periods and up a group.
by Salma Quintanilla 1J
Sun Oct 29, 2017 2:32 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius vs. Ionic Radius [ENDORSED]
Replies: 4
Views: 321

Re: Atomic Radius vs. Ionic Radius [ENDORSED]

Atomic radius is half the distance between centers of neighboring atoms and ionic radius is two ions that are joined by an ionic bond.
by Salma Quintanilla 1J
Mon Oct 02, 2017 5:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1180491

Re: Post All Chemistry Jokes Here

https://goo.gl/images/1Emecf

More reasons to love trader joe's....."Avogadro makes mole and avocados make guacamole."

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