Search found 63 matches
- Sat Mar 16, 2019 8:58 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Bimolecular
- Replies: 13
- Views: 2179
Re: Bimolecular
Bimolecular means that for a certain reaction there are two reactants. There's also unimolecular where there is only 1 reactant in the reaction and termolecular for three reactants.
- Sat Mar 16, 2019 8:54 pm
- Forum: Zero Order Reactions
- Topic: third order
- Replies: 11
- Views: 1161
Re: third order
The textbook says their are mostly uncommon. It may be useful to know because they may appear when asked for overall reaction order.
- Sat Mar 16, 2019 8:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7386
Re: LYNDON'S PORK RAMEN REVIEW
For Q7, how come we don't the number of electrons for the half reactions given when adding them to get the overall reaction?
- Sat Mar 16, 2019 8:41 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Endergonic
- Replies: 2
- Views: 228
Re: Endergonic
Yes, endergonic is deltaG>0 and exergonic is deltaG<0.
- Sat Mar 16, 2019 8:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: k(1)/k(-1)
- Replies: 4
- Views: 590
Re: k(1)/k(-1)
k' is referring to the reverse reaction.
- Sat Mar 16, 2019 8:18 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 1
- Views: 459
Re: Midterm
It has to do with the temperature. SInce we are increasing the temperature, and the reaction in endothermic this will accelerate the reaction meaning more product will form, so the equilibrium would shift to the right.
- Sat Mar 16, 2019 8:11 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 1
- Views: 427
Re: Midterm
This is the link to the midterm solutions: https://lavelle.chem.ucla.edu/wp-conten ... am_ans.pdf
- Sat Mar 16, 2019 8:10 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Approaches to mechanisms
- Replies: 2
- Views: 312
Re: Approaches to mechanisms
In lecture professor Lavelle mentioned that we only need to focus on the Pre-Equilibrium approach.
- Sat Mar 16, 2019 8:09 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: FORMULAS
- Replies: 3
- Views: 505
Re: FORMULAS
I know that in the 14B website there is a link to the equation list we are given for the test.
- Sat Mar 16, 2019 1:50 pm
- Forum: Ideal Gases
- Topic: Bar for partial pressure [ENDORSED]
- Replies: 4
- Views: 687
Re: Bar for partial pressure [ENDORSED]
Bar is the proper unit for partial pressure for equilibrium constant calculations.
- Sat Mar 16, 2019 1:38 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Final [ENDORSED]
- Replies: 9
- Views: 1099
Re: Final [ENDORSED]
I think they did mention we would be given a sheet like the one for test 2.
- Sat Mar 16, 2019 1:37 pm
- Forum: Student Social/Study Group
- Topic: Solutions for Tests 1 and 2
- Replies: 7
- Views: 1129
Re: Solutions for Tests 1 and 2
I don't think they post the solutions for the tests because there is usually a review session by a TA where they go over the solutions.
- Sat Mar 16, 2019 1:36 pm
- Forum: Balancing Redox Reactions
- Topic: How to tell if its in acidic or basic
- Replies: 6
- Views: 660
Re: How to tell if its in acidic or basic
The problem would state whether it is in a basic or acidic solution.
- Sat Mar 16, 2019 11:30 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K'
- Replies: 4
- Views: 511
K'
What is k' and when are we supposed to use it?
- Fri Mar 15, 2019 5:24 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 2
- Views: 495
Test 2
Help with the question: rank in order of increasing oxidation power going from their second oxidation state to neutral: Ti2+, Sn2+, Mg2+.
What lets us know their rank?
What lets us know their rank?
- Fri Mar 15, 2019 5:22 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 5
- Views: 463
Test 2
Can someone help with this question from test 2.
Rank the following species in order of increasing reducing power going from their neutral to second oxidation state: Pt, Pb, Cu.
How do we know this?
Rank the following species in order of increasing reducing power going from their neutral to second oxidation state: Pt, Pb, Cu.
How do we know this?
- Fri Mar 15, 2019 11:23 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: DeltaS Total
- Replies: 2
- Views: 559
Re: DeltaS Total
I believe it is when it's at equilibrium.
- Fri Mar 15, 2019 11:21 am
- Forum: First Order Reactions
- Topic: Doubling Concentrations
- Replies: 3
- Views: 381
Re: Doubling Concentrations
If you are talking about a first order reaction the doubling of a reactant means the reaction rate is doubled. If it's a second order reaction then the reaction rate is increase by a factor of x^2, where x would be your reaction rate.
- Fri Mar 15, 2019 11:16 am
- Forum: Second Order Reactions
- Topic: units of K
- Replies: 3
- Views: 666
Re: units of K
For a second order reaction k is Lx mol^-1x s^-1.
- Fri Mar 15, 2019 11:15 am
- Forum: First Order Reactions
- Topic: Reaction Orders
- Replies: 1
- Views: 190
Re: Reaction Orders
In the textbook it is mentioned how the reaction order can be a negative number=negative order . This would signify that the concentration value of the species is in the denominator of the rate law. The species in this case is usually a product and it represents the reverse reaction.
- Fri Mar 15, 2019 11:11 am
- Forum: Zero Order Reactions
- Topic: Zero-order reactions
- Replies: 4
- Views: 663
Zero-order reactions
What are the units for a zero order reaction, if any?
- Tue Feb 26, 2019 11:22 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Agents and Species
- Replies: 3
- Views: 340
Agents and Species
What is the difference between a reducing agent and a reduced species? And an oxidizing agent vs a oxidized species?
- Tue Feb 26, 2019 10:48 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Question for Test 2
- Replies: 4
- Views: 421
Re: Question for Test 2
Since that was part of the last lecture covering the topics of test 2 I would assume we do need to know it.
- Tue Feb 26, 2019 7:41 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell potential
- Replies: 2
- Views: 299
Cell potential
Does the value of the cell potential/E change if the value of your stoichiometric coefficient of one reactant changes?
- Mon Feb 25, 2019 6:26 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Difference in values
- Replies: 2
- Views: 267
Difference in values
What is the diffrenece between Ecell and E^o cell?
- Tue Feb 12, 2019 2:34 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Example 8.3 sixth edition
- Replies: 3
- Views: 391
Example 8.3 sixth edition
In the sixth edition textbook the example problem for specific heat and molar heat states that the temperature changes from 20C to 100C. In their work however they treated the deltaT as 80.K. My question is why they didn't convert 80C to 353K?
- Tue Feb 12, 2019 2:29 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=mCdeltaT
- Replies: 15
- Views: 8103
Re: q=mCdeltaT
If you are given moles then use n and molar heat capacity, nad if you are given mass (g) then use m and specific heat capacity of the substance.
- Sun Feb 10, 2019 3:43 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Clarifying about Midterm
- Replies: 4
- Views: 445
Re: Clarifying about Midterm
I would say that it is only focused on the topics covered in class and if you are using the textbook to only focus on the section of the chapters that come before the Gibbs Free energy section. In the case of the 6th edition it would be to only go up to section 9.11 from Chapter 9.
- Sun Feb 10, 2019 3:39 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Converting Celsius to Kelvin
- Replies: 7
- Views: 667
Re: Converting Celsius to Kelvin
In the examples we have done in class we have added 273K.
- Sun Feb 10, 2019 3:38 pm
- Forum: Ideal Gases
- Topic: pH and pOH
- Replies: 18
- Views: 1850
Re: pH and pOH
Usually the problem you are solving will tell you which one to solve for. In some occasions you may have to solve for both for the same problem.
- Fri Dec 07, 2018 8:30 pm
- Forum: Lewis Structures
- Topic: Lone electrons and polarity
- Replies: 1
- Views: 176
Re: Lone electrons and polarity
I don't think that lone pairs affect the polarity of an atom. Instead its electronegativity and the atomic radius would affect how likely it would be able for its electron cloud to be distorted.
Re: Naming
You have to see what the charge would be on the compound to figure out how many potassium molecules would neitralize that charge.
- Fri Dec 07, 2018 8:20 pm
- Forum: General Science Questions
- Topic: what specifically makes thymine a base.
- Replies: 2
- Views: 568
Re: what specifically makes thymine a base.
Following the answer above, the nitrogen would make the thymine the base because it has a lone pair electrons.
- Fri Dec 07, 2018 8:16 pm
- Forum: Lewis Acids & Bases
- Topic: Why is water always a lewis base?
- Replies: 2
- Views: 280
Re: Why is water always a lewis base?
It depends on the reaction because water is considered to be amphoteric meaning it can be an acid or base.
- Fri Dec 07, 2018 8:15 pm
- Forum: General Science Questions
- Topic: PH3 or NH3
- Replies: 2
- Views: 1870
Re: PH3 or NH3
NH3 would have a higher boiling point because the nitrogen forms bonds with H. Remember that for intermolecular forces it goes from Van der Waals, dipole-dipole to H-binding as the strongest.
- Fri Dec 07, 2018 8:13 pm
- Forum: Amphoteric Compounds
- Topic: What makes something amphoteric?
- Replies: 6
- Views: 791
Re: What makes something amphoteric?
H2O is amphoteric because it can be an acid or base. This means is can either accept an electron or donate an electron.
- Fri Dec 07, 2018 8:11 pm
- Forum: General Science Questions
- Topic: what determines boiling point
- Replies: 2
- Views: 585
Re: what determines boiling point
Boiling point from least to greatest is Van der Walls, dipole-dipole and H-bonds.What helps determine boiling point can also be the size of the molecule because the bigger the molecule, the more London forces which also leads to a higher boiling point.
- Fri Dec 07, 2018 8:09 pm
- Forum: General Science Questions
- Topic: Finals
- Replies: 4
- Views: 710
Re: Finals
All topics will be covered in the syllabus, so you should be able to understand quantum as equally as the other topics.
- Fri Dec 07, 2018 8:08 pm
- Forum: General Science Questions
- Topic: amphiprotic
- Replies: 3
- Views: 603
Re: amphiprotic
Amphiprotic is when the compound can either donate or accept a hydrogen.
- Fri Dec 07, 2018 8:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 20830
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Can someone explain why hemogrlobin is tetradentrate but cisplatin is monodentrate?
- Thu Dec 06, 2018 8:25 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: How to tell if something is a chelate
- Replies: 6
- Views: 576
Re: How to tell if something is a chelate
I think that a chelate is when the ring structured compound binds a central metal at two or more places.
- Thu Dec 06, 2018 8:20 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH calculation
- Replies: 4
- Views: 537
pH calculation
When we are loking for pH why is pH= log10[H30]? How do we know what the value of [H3O] is?
- Tue Dec 04, 2018 11:01 pm
- Forum: Biological Examples
- Topic: Ligands
- Replies: 7
- Views: 857
Ligands
When given a chemical formula how do we know which one is the cetral metal atom or ion?
- Tue Dec 04, 2018 9:51 pm
- Forum: Lewis Structures
- Topic: Lewis Structure bonds
- Replies: 4
- Views: 410
Re: Lewis Structure bonds
So to make sure we have the correct Lewis structure we calculate the formal charge of the possible structures we have drawn?
- Tue Dec 04, 2018 9:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 11
- Views: 907
Re: Lone Pairs
Lone pairs affect the structure of the VSEPR model beacues they have the highest repulsion so they try to be fathest apart from each other. Also they cause repulsion with the other atoms bonded with the central atom which is why the angles of some shapes turn out to be slightly smaller than the orig...
- Tue Dec 04, 2018 9:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 11
- Views: 907
Re: Lone Pairs
Lone pairs are the pair of electrons that do not get shared with another atom in the molecule.Arlene Linares 3A wrote:Can someone explain lone pairs to me?
- Tue Dec 04, 2018 9:36 pm
- Forum: General Science Questions
- Topic: Can We Take The Final In Pencil?
- Replies: 14
- Views: 1545
Re: Can We Take The Final In Pencil?
I think you are only allowed to write the tests in pen. Atleast for the midterm they mentioned that only what was written in pen would be graded. This seems reasonable to since we receive our tests back after they are graded and things written in pencil can easily be erased.
- Tue Dec 04, 2018 9:31 pm
- Forum: Lewis Structures
- Topic: Lewis Structure bonds
- Replies: 4
- Views: 410
Lewis Structure bonds
How do you know when. you need to form a double bond or if the bond between the atoms must stay as single bonds?
- Tue Dec 04, 2018 9:28 pm
- Forum: Sigma & Pi Bonds
- Topic: Number of sigma and pi bonds
- Replies: 5
- Views: 1023
Re: Number of sigma and pi bonds
You would still have to draw the Lewis structure ( with help of the hybridization) to see whether the bonds are single, double and triple bonds. Once you know the structure the number of sigma bonds are the number of. single bonds and the pi bonds are any bonds starting from the second bond. This me...
- Thu Nov 29, 2018 12:16 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 1
- Views: 97
Bond Angles
When we are considering the bond angles, for molecules with lone pairs do we consider the bond lengths of the electron arrangement or of the molecular shape?
- Wed Nov 28, 2018 4:20 pm
- Forum: Electronegativity
- Topic: Ionic Character
- Replies: 7
- Views: 1511
Re: Ionic Character
Electronegativity decreases down a group since Cl is lower than O, I want to.say that O is more electronegative than Cl.
- Wed Nov 28, 2018 4:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Bond Angles
- Replies: 6
- Views: 16040
Re: Seesaw Bond Angles
The lone pair is placed on the axis of the molecule. This is the Axail lone pair and it is placed in this position because of the repulsion of the atoms from the electron pair.
- Wed Nov 28, 2018 4:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar and Non-Polar
- Replies: 2
- Views: 244
Polar and Non-Polar
When we are trying to answer whether a molecule is polar or non polar how do we determine the direction of the bond?
- Wed Nov 28, 2018 4:09 pm
- Forum: Hybridization
- Topic: Polar Power
- Replies: 5
- Views: 451
Re: Polar Power
The atomic radii helps you understand why the polarizing power increases or decreases since the size of the radius correlates with how much power the nucleus has on the valence electrons.
- Wed Nov 28, 2018 4:06 pm
- Forum: Lewis Structures
- Topic: Lewis structures vs VSEPR
- Replies: 2
- Views: 187
Re: Lewis structures vs VSEPR
For VSEPR since the central atom is the "important atom" we only focus on the shared electron it has with the other atoms. Because of this it is not necessary to dram the valence electrons of the other atoms.
- Sat Nov 03, 2018 10:19 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum number Ms
- Replies: 3
- Views: 679
Quantum number Ms
How do we know when the Ms quantum number should be -1/2, or 1/2?
- Thu Oct 25, 2018 6:37 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum numbers
- Replies: 3
- Views: 453
Quantum numbers
What is the difference between principal quantum number and magnetic quantum number?
- Thu Oct 25, 2018 6:35 pm
- Forum: Photoelectric Effect
- Topic: unit conversion hw Q 1.3
- Replies: 7
- Views: 838
Re: unit conversion hw Q 1.3
You should convert the given values to the required SI units before plugging them into the equation you are using (like e=hv etc) that way when you are solving the problem you are able to "cross out" the units that you don't need in your final answer. At the end, if they are asking for a c...
- Thu Oct 25, 2018 6:29 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Constants and Equations
- Replies: 2
- Views: 233
Re: Constants and Equations
The front page of every exam should gave the general equations and constants that you will need.
- Thu Oct 04, 2018 8:22 pm
- Forum: Significant Figures
- Topic: Determining Sig Figs
- Replies: 6
- Views: 421
Re: Determining Sig Figs
You may also want to refer to Dr. Lavelle's "Math Assistance" section where he has two documents that goes over the use of significant figures thoroughly!
- Thu Oct 04, 2018 8:19 pm
- Forum: Significant Figures
- Topic: Determining Sig Figs
- Replies: 6
- Views: 421
Re: Determining Sig Figs
When you are multiplying you must use the smallest number of significant figures in your data to be the number of significant figures in your answer. For example, if you are multiplying 6.18165 x 3.56=22.0 your answer must only have 3 significant figures since that is the smallest number of signific...
- Thu Oct 04, 2018 8:13 pm
- Forum: Balancing Chemical Reactions
- Topic: Net number of molecules
- Replies: 3
- Views: 489
Re: Net number of molecules
The net number of molecules would be the difference between the number of moles produced minus the number of moles you began with. You will know the number of moles of your reactants and products by adding the given coefficients in front of their respective molecules form the reaction. (Make sure yo...
- Thu Oct 04, 2018 8:06 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 8167
Re: How does grading for discussion posts work?
Raquel Rodriguez wrote:Do you guys know when our first test is?
It would be during your discussion section in week 2.