Search found 100 matches
- Fri Mar 12, 2021 5:43 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Sapling #4
- Replies: 6
- Views: 518
Re: Sapling #4
I'm not positive that this is correct. However, I think since it says per mole of gas and the number of moles aren't given, you can assume that n=1.
- Fri Mar 12, 2021 5:31 pm
- Forum: General Rate Laws
- Topic: k vs K
- Replies: 6
- Views: 413
Re: k vs K
I think that K is the rate constant when you take into account the forward and reverse reactions (multiple reactants) but k only takes into account the forward reaction when you only have one reactant. I'm not sure though. I think this is correct. K is equal to k/k', so it's taking into account the...
- Fri Mar 12, 2021 5:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 4D.3 Textbook
- Replies: 1
- Views: 186
Re: 4D.3 Textbook
Hi, I'm not entirely sure if I understand your question, bu I think that the problem is asking for the delta U in regards to moles of CO specifically. So instead of just leaving it as -2.058 kJ, you need to divide that by the number of moles, which you get by converting the grams of CO to moles of C...
- Fri Mar 12, 2021 12:59 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Temperature change in isobaric compression
- Replies: 1
- Views: 281
Re: Temperature change in isobaric compression
I also think the temperature would decrease because, like you said, of the relationship between volume and temperature. Using PV=nRT, you can see that if pressure, the number of moles, and the gas constant are all constant, then temperature would have to decrease. The temperature would decrease to c...
- Fri Mar 12, 2021 12:53 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Thermodynamics Rules/Concepts
- Replies: 3
- Views: 354
Re: Thermodynamics Rules/Concepts
- If a reaction is reversible, then \Delta S_{tot}=0 and \Delta S_{surr}=-\Delta S_{sys} -If a reaction is irreversible, then \Delta S_{surr}=0 so \Delta S_{tot}=\Delta S_{sys} Also would like to add that I think work doesn't equal zero in isobaric (constant pressure) conditions ! w=-P \Delta V so ...
- Sun Mar 07, 2021 10:55 am
- Forum: General Rate Laws
- Topic: Youtube Review
- Replies: 17
- Views: 985
Re: Youtube Review
Hi! I think that the organic chemistry tutor on Youtube does a good job and has really helped me this quarter
- Sun Mar 07, 2021 10:43 am
- Forum: Balancing Redox Reactions
- Topic: Balancing Reactions Help
- Replies: 5
- Views: 328
Re: Balancing Reactions Help
Hi! I'm sure that khan academy or the organic chemistry tutor on YouTube have some videos that work through examples on how to do problems with balancing reactions.
- Sun Mar 07, 2021 10:37 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Textbook Problem 6N.13
- Replies: 6
- Views: 656
Re: Textbook Problem 6N.13
Hi, I also got the same answer as you. I think the answer key must have rounded a number somewhere because I got lnQ=14.79, and they used lnQ=15. I think they just forgot to put the number before 10^6? Even if you use lnQ=15, you don't get just 10^6. Hope this helps
- Sun Mar 07, 2021 10:27 am
- Forum: Zero Order Reactions
- Topic: Overall order of the reaction
- Replies: 45
- Views: 2010
Re: Overall order of the reaction
You can determine the overall order of a reaction by taking the sum of the orders of the individual reactants
- Sun Mar 07, 2021 10:24 am
- Forum: Administrative Questions and Class Announcements
- Topic: Final Exam Time
- Replies: 47
- Views: 2471
Re: Final Exam Time
Lavelle's website says Sunday, March 14th, from 9:30-11:00
- Sat Feb 27, 2021 2:51 pm
- Forum: Balancing Redox Reactions
- Topic: sapling week 8 #18
- Replies: 4
- Views: 355
Re: sapling week 8 #18
Just like Will said, when you’re balancing the equation, think of Fe2O3•3H2O as one unit. if you put a coefficient infront of the Fe2O3•3H2O, then that coefficient is distributed to the 3H2O.
- Fri Feb 26, 2021 9:59 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 7/8 #5 (oxidizing agent)
- Replies: 1
- Views: 144
Re: Sapling Week 7/8 #5 (oxidizing agent)
So under the skeletal reaction you have that Mn has a charge of 3+ and the O4 has an overall charge of 4-. O has a charge of 2-, so if there are four oxygen atoms, then the total charge would be 8-. In order to get the 1- charge for the whole molecule, Mn would have a charge of 7+ on the reactants s...
- Fri Feb 26, 2021 9:51 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Gibbs Free Energy Equation and n
- Replies: 13
- Views: 618
Re: Gibbs Free Energy Equation and n
Alvin Lai 3J wrote:I think it is the moles of electrons transferred, which you can find my looking at the redox reaction?
Yeah it the moles of electrons that were used in balancing the redox reaction
- Fri Feb 26, 2021 9:50 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Moles in ΔG = -nFE
- Replies: 45
- Views: 4090
Re: Moles in ΔG = -nFE
The number of moles of electrons that were used in balancing the redox reaction is plugged into the delta G equation.
- Thu Feb 25, 2021 10:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Order of cell diagrams
- Replies: 4
- Views: 325
Re: Order of cell diagrams
My TA said that we should always put the aqueous solutions on either side of the salt bridge
- Sat Feb 20, 2021 8:16 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Solids and Liquids?
- Replies: 26
- Views: 1490
Re: Solids and Liquids?
I don't think changing the amount of aqueous solutions applies here, just gases.
- Sat Feb 20, 2021 8:12 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U and Delta H
- Replies: 12
- Views: 4649
Re: Delta U and Delta H
At constant pressure: delta H = delta U + P(delta V)
Under conditions of constant pressure and volume: delta V would become zero, and delta H would equal delta U.
Under conditions of constant pressure and temperature: delta H = delta U + (delta n)RT
Under conditions of constant pressure and volume: delta V would become zero, and delta H would equal delta U.
Under conditions of constant pressure and temperature: delta H = delta U + (delta n)RT
- Sat Feb 20, 2021 8:05 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: H vs q
- Replies: 20
- Views: 925
Re: H vs q
q is the heat consumed or released by the system, while enthalpy is the heat at constant pressure. q only equals delta H when q=qp, which is under conditions of constant pressure.
- Sat Feb 20, 2021 7:59 am
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Degeneracy and Entropy
- Replies: 6
- Views: 555
Re: Degeneracy and Entropy
Degeneracy is the number of different states that energy can exist and entropy increases as there are potentially more ways for energy to exist, so as degeneracy increases, entropy does as well.
- Fri Feb 19, 2021 9:56 am
- Forum: Van't Hoff Equation
- Topic: Outline 4 van't Hoff bullet point
- Replies: 6
- Views: 553
Re: Outline 4 van't Hoff bullet point
Example 5J.5 in the textbook explains how use van't Hoff's equation really well. Hope this helps.
- Sat Feb 13, 2021 10:00 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q vs -q
- Replies: 9
- Views: 564
Re: q vs -q
They write it this way because regardless if q(reaction) is positive or negative, q(calorimeter) will always have the opposite sign. For this problem, q(reaction) is negative because it's an exothermic reaction. If the reaction is exothermic, then that means the calorimeter is gaining that heat, whi...
- Sat Feb 13, 2021 9:47 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Units of W
- Replies: 16
- Views: 819
Re: Units of W
I also don't think degeneracy has any units because it's just the number of states raised to the number of particles. Like Saumya said, I think it's just a quantitive term.
- Sat Feb 13, 2021 1:40 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Example 4.F.4
- Replies: 2
- Views: 195
Re: Example 4.F.4
In example 4.F.4 page 302, it shows they used the calculation \Delta S=C v ln(T2/T1) with C v =nC v,m So C v should be equal to (3/2)R, or 12.5. However, the textbook shows 20.79, which is actually equal to (5/2)R, or C p . Is this a mistake? Should Cv be used, or is the calculation correct in usin...
- Sat Feb 13, 2021 1:34 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Difference between ΔS° and ΔS
- Replies: 9
- Views: 3010
Re: Difference between ΔS° and ΔS
Delta G naught and delta S naught are the changes in Gibbs free energy and entropy at equilibrium, while delta G and delta S are relevant under other conditions.
- Sat Feb 13, 2021 12:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Textbook 4.45
- Replies: 1
- Views: 124
Re: Textbook 4.45
To answer your question about part (a), the change in enthalpy is a positive number for the dissolution, so the change in entropy for the surroundings is negative. For the dissolution to be favored, the change in entropy must be positive because spontaneous/favored processes require an increase one ...
- Sun Feb 07, 2021 12:40 pm
- Forum: Phase Changes & Related Calculations
- Topic: Water's Heating Curve
- Replies: 9
- Views: 598
Re: Water's Heating Curve
To add on to what was said about steam causing worse burns than boiling water, steam has a lot more kinetic energy than boiling water. This means that when the steam touches skin, it releases a lot more energy upon the skin than boiling water does.
- Sun Feb 07, 2021 12:29 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Positive and Negative q Value
- Replies: 19
- Views: 13396
Re: Positive and Negative q Value
Hi! So just by looking at the equation q=m*C*delta T, we know that m and C are always going to be positive. This means that the only term that can affect whether q is positive of negative is delta T. If the final temperature is lower than the initial temperature, then the overall change in temperatu...
- Sun Feb 07, 2021 12:21 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4C.3 Change in Enthalpy
- Replies: 6
- Views: 538
Re: 4C.3 Change in Enthalpy
Joey_Okumura_1E wrote:The answer for 4C.3a is missing from the solution. Did you get the following answers:
4C.3a ΔH = 765 J, Tf = 343 K
Yeah, I also got that for part (a)
- Sun Feb 07, 2021 12:04 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isothermal (reversible) vs. Irreversible
- Replies: 5
- Views: 259
Re: Isothermal (reversible) vs. Irreversible
One main difference between irreversible and reversible expansions has to do with pressure. Irreversible expansion happens under a constant pressure, which means the external and internal pressure are equivalent. For reversible expansion, the external and internal pressures are different.
- Sun Feb 07, 2021 11:52 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sapling #19 Weeks 3/4
- Replies: 4
- Views: 234
Re: Sapling #19 Weeks 3/4
Just to add on to what Lillian said, q(calorimeter)+q(reaction)=0, so q(calorimeter) = -q(reaction).
- Sat Jan 30, 2021 10:41 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4E.5 C-C Bond Enthalpy
- Replies: 6
- Views: 297
Re: 4E.5 C-C Bond Enthalpy
The C-H bonds are not taken into account because both structures have 6 of them, so there is no difference in regards to the C-H bonds between the structures. The question only asks for the difference between the C-C bonds.
- Sat Jan 30, 2021 9:19 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding a gas
- Replies: 26
- Views: 1166
Re: Adding a gas
The addition of an inert gas, like argon, does not affect the reaction.
- Sat Jan 30, 2021 9:13 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: percent ionization
- Replies: 7
- Views: 3697
Re: percent ionization
sort of going off the original question, can someone briefly explain what deprotonation is again please? The percentage deprotonation is the ratio of the concentration of dissociated [H+] ions to the concentration of initial acid [HA]. You use it to find what percentage of the weak acid has dissoci...
- Sat Jan 30, 2021 9:01 am
- Forum: General Science Questions
- Topic: MT 1 Grades
- Replies: 8
- Views: 437
Re: MT 1 Grades
Last quarter it took about a week for exams with no partial credit, so I assume that the grades for this exam will take longer because there is partial credit.
- Thu Jan 28, 2021 5:10 pm
- Forum: Phase Changes & Related Calculations
- Topic: reaction shifts
- Replies: 18
- Views: 806
Re: reaction shifts
It might be helpful to think of heat as a regular product or reactant. Just as if we raise the concentration of reactants, the forward reaction will be favored. If the reaction is endothermic, which means heat is on the reactants side, then increasing the temperature ( kind of like "raising the...
- Sat Jan 23, 2021 6:44 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Why can solvents affect equilibrium?
- Replies: 4
- Views: 245
Re: Why can solvents affect equilibrium?
An increase in H20 is not affecting the equilibrium constant, it is just affecting the direction in which the reaction proceeds. Just like for any increase in product or reactant, the reaction will favor a direction in order to deal with the increase.
- Sat Jan 23, 2021 6:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Table 5G2 - K vs Kc
- Replies: 4
- Views: 144
Re: Table 5G2 - K vs Kc
Yeah I agree with the people above. I also just assumed that K meant Kp because the other column was labeled as Kc
- Sat Jan 23, 2021 6:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 2 Hw 5
- Replies: 6
- Views: 349
Re: Sapling Week 2 Hw 5
To answer the first part of your question, the 5% rule applies to both percent protonation and ionization
- Sat Jan 23, 2021 6:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pKa and Ka
- Replies: 27
- Views: 998
Re: pKa and Ka
Yeah "p" is just shorthand for -log, so you're right to say that pKa is just the negative log of Ka
- Sat Jan 23, 2021 6:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Studying for Midterm #1
- Replies: 63
- Views: 2755
Re: Studying for Midterm #1
Doing the textbook problems listed in the outlines are extremely helpful. Also, going through the bullet points of learning objectives on each outline is a good way to check your understanding of that unit.
- Thu Jan 14, 2021 10:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pH and pOH vs. pKa and pKb
- Replies: 9
- Views: 555
Re: pH and pOH vs. pKa and pKb
While pH and pKa both measure acidity, they do so in different ways and are not exactly equal. pH is calculated by -log[H3O+], and pKa is calculated by -log [H3O+][conj base]/[acid]. Same goes for pOH and pKb. Hope this helps!
- Thu Jan 14, 2021 10:40 pm
- Forum: Ideal Gases
- Topic: Question 4 Sapling [ENDORSED]
- Replies: 8
- Views: 413
Re: Question 4 Sapling [ENDORSED]
Your approach to this problem is correct. Make sure you are using 1/Kp in this case because you are starting with the products.
- Thu Jan 14, 2021 10:15 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K on and reactant/product concentrations
- Replies: 8
- Views: 269
Re: Q and K on and reactant/product concentrations
Ellison Gonzales 1H wrote:Could someone list what terms are used when talking about Q? I get a bit confused on which terms are used for K or Q
K is the equilibrium constant, while Q is the reaction quotient.
- Thu Jan 14, 2021 10:12 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: aqueous solutions
- Replies: 9
- Views: 387
Re: aqueous solutions
Aqueous solutions are included. Only solids and liquids are omitted because their concentrations do not change significantly.
- Thu Jan 14, 2021 10:03 pm
- Forum: Ideal Gases
- Topic: Thermodynamics in Equilibirum
- Replies: 6
- Views: 246
Re: Thermodynamics in Equilibirum
He mentioned in one of the lectures that he was going to cover thermodynamics later
- Fri Jan 08, 2021 3:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Favoring
- Replies: 6
- Views: 263
Re: Favoring
If the reaction requires heat (endothermic) while forming product, then increasing the temperature will result in product formation being favored. On the other hand, if the reaction gives off heat (exothermic) while forming product, then increasing the temperature will realist in reactant formation ...
- Fri Jan 08, 2021 3:26 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Chem Equilibrium Part 4 #14
- Replies: 2
- Views: 385
Re: Chem Equilibrium Part 4 #14
I agree with you on (i), but I came up with something different for the other two. For (iii), I agree that the change in pressure wouldn't affect the NO. However, I thought that it would be because it was inert gas being added, not because of the number of moles. As for (ii), I'm a little confused m...
- Fri Jan 08, 2021 3:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating Equilibrium Concentrations with Quadratic & Cubic Equations
- Replies: 5
- Views: 243
Re: Calculating Equilibrium Concentrations with Quadratic & Cubic Equations
Yeah, I agree with Claire. I think you could get a reasonable answer by approximating, but you're probably better off just doing the math for a more accurate answer. Also, since Dr. Lavelle never mentioned using approximation in a problem with a quadratic, I think it's safe to say to just do the math.
- Fri Jan 08, 2021 3:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Table concentrations
- Replies: 3
- Views: 219
Re: ICE Table concentrations
I think Dr. Lavelle said that we will mainly just see quadratics. If we are presented with a cubic expression, then it will most likely be a problem in which approximation can used to solve it.
- Wed Jan 06, 2021 10:41 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K trend/similarity
- Replies: 8
- Views: 363
Re: Q and K trend/similarity
Do the Q and the K values follow the same trend/pattern when describing on whether a system will favor reactants/products? For example in the lecture, it states if K is small, then it would favor the products (shift right) since there's more reactants at equilibrium. And if Q is smaller than K, the...
- Fri Dec 11, 2020 11:05 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: What are electron donating groups?
- Replies: 3
- Views: 209
Re: What are electron donating groups?
You can determine an electron donating group by look at the central atom of the group and noting if it has a lone pair or not. If it has a lone pair on the central atom, then I think it is safe to assume that it is an electron donating group. Feel free to correct me if I'm wrong. Hope this helps!
- Fri Dec 11, 2020 11:02 pm
- Forum: Amphoteric Compounds
- Topic: Metalloid Line
- Replies: 2
- Views: 298
Re: Metalloid Line
https://www.google.com/url?sa=i&url=https%3A%2F%2Fslideplayer.com%2Fslide%2F11923338%2F&psig=AOvVaw2ZxNlAAo1AHy7aHRwbiWoJ&ust=1607842862051000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNDG9sjvx-0CFQAAAAAdAAAAABAD Here is picture depicting the amphoteric line against the metalloi...
- Fri Dec 11, 2020 10:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 7
- Views: 424
Re: Final
Did Lavelle already send out an email regarding the instructions for the final?
- Fri Dec 11, 2020 10:53 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Sapling 5
- Replies: 2
- Views: 119
Re: Sapling 5
I found the [OH-] after finding the pOH. I just did 10^-(pOH). I found that this is the easier way for me since you already needed to find the pOH. Hope this helps!
- Fri Dec 11, 2020 10:50 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: H20
- Replies: 6
- Views: 607
Re: H20
H20 is considered monodentate because only one lone pair bonds a central atom, while the other lone pair points away from the central atom. Hope this helps!
- Wed Dec 09, 2020 7:01 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Question
- Replies: 6
- Views: 358
Re: Final Question
Hi! I don't know exactly how much of acids and bases is going to be on the final, but I'd say everything Dr. Lavelle has gone over is probably fair game. I would assume only a small portion of the test will be on acids and bases because he'll want to get in all the other units too.
- Thu Dec 03, 2020 9:37 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: OH calculation
- Replies: 2
- Views: 147
Re: OH calculation
Yeah, it's basically calculated the same way. Like it was stated above, if you have the pH, then you can just subtract the pH from 14 to get the pOH.
- Thu Dec 03, 2020 9:33 pm
- Forum: *Stereochemistry
- Topic: What is the difference between cis and trans?
- Replies: 9
- Views: 1773
Re: What is the difference between cis and trans?
CIs configuration refers to two groups being on the same side of a molecule, while trans refers to the two groups being on opposite sides of each other.
- Thu Dec 03, 2020 9:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: List of Polydentate Ligands
- Replies: 3
- Views: 1212
Re: List of Polydentate Ligands
Hi, if you're talking about the sheet on sapling, then there's a column that tells you on about the denticity.
- Thu Dec 03, 2020 9:19 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Compound
- Replies: 6
- Views: 319
Re: Coordination Compound
Sahaj Patel- Lec 2 and Dis 2L wrote:That seems correct, but remember that the overall compound will have a +1 charge that is cancelled out by Bromine!
Hey I'm just a little confused because there are two Bromines. So wouldn't the compound have a 2+ charge that the two bromines cancel out? Feel free to correct me if I'm wrong
- Thu Dec 03, 2020 9:12 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: homework 9 #5
- Replies: 6
- Views: 372
Re: homework 9 #5
Tanya Nguyen 1E wrote:What is (en)? Is it just a symbol for a bidentate ligand or is it a specific ligand?
it's ethylene diamine
- Sat Nov 28, 2020 8:48 pm
- Forum: Sigma & Pi Bonds
- Topic: Delocalized Pi bond
- Replies: 6
- Views: 417
Re: Delocalized Pi bond
George_Yin_3I wrote:Delocalized pi bonds occur when pi bonds extend to more than 2 atoms. There is an exercise on Sapling about that.
Yeah I think it is question 16
- Sat Nov 28, 2020 8:37 pm
- Forum: Hybridization
- Topic: Hybridization and double bonds
- Replies: 3
- Views: 234
Re: Hybridization and double bonds
When talking about hybridization you need to consider regions of electron density. Therefore when determining hybridization you consider atoms and lone pairs. For a double bond, the hybridization of each atom becomes sp2 instead of sp3. Hope this helps. Like she said, you just need to focus on the ...
- Sat Nov 28, 2020 8:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 15
- Views: 660
Re: Final
America Alvarado wrote:Where are the dates for the test?
I think you can find it on myucla under your study list
- Sat Nov 28, 2020 8:19 pm
- Forum: Lewis Acids & Bases
- Topic: question 17 sapling
- Replies: 7
- Views: 384
Re: question 17 sapling
There should be no resonance structures, the last one you are missing is the carbons forming a triangle shape with their bonds. hi when do we know not to include a resonance structure? or should we just assume that for all questions? thank you so much for your response btw I think resonance structu...
- Sat Nov 28, 2020 8:15 pm
- Forum: Lewis Acids & Bases
- Topic: question 17 sapling
- Replies: 7
- Views: 384
Re: question 17 sapling
The third structure should utilize a triangular ring, with one hydrogen bonded to each of the two carbons and two hydrogens bonded to the remaining third carbon.
- Thu Nov 26, 2020 11:08 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chem Community Posts during Thanksgiving break
- Replies: 10
- Views: 548
Re: Chem Community Posts during Thanksgiving break
Aliya 2J wrote:If we stacked up with 40 from before, do we need to do more to have them be from this week?
I think so. I think we need to have at least five posts per week
- Sun Nov 22, 2020 8:24 pm
- Forum: Hybridization
- Topic: Shape of Hybrid Orbital
- Replies: 5
- Views: 412
Re: Shape of Hybrid Orbital
I think the sp3 hybrid orbital looks like a somewhat distorted p-orbital with unequal lobes
- Sun Nov 22, 2020 8:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: polarity of trans-dichlorethene
- Replies: 4
- Views: 183
Re: polarity of trans-dichlorethene
If the chlorines are on opposite sides of the molecule, then their dipole moments cancel out
- Tue Nov 17, 2020 11:14 pm
- Forum: Student Social/Study Group
- Topic: Midterm 2
- Replies: 19
- Views: 1039
Re: Midterm 2
I'm just going through the textbook problems. I found that they were the most helpful in preparing for the last midterm.
- Tue Nov 17, 2020 10:44 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: variations in electron configuration names
- Replies: 3
- Views: 180
variations in electron configuration names
Is there a difference between valence shell configuration and ground state configuration?
- Fri Nov 13, 2020 10:57 pm
- Forum: Sigma & Pi Bonds
- Topic: Triple bond?
- Replies: 21
- Views: 902
Re: Triple bond?
Madison Muggeo 1G wrote:darchen3G wrote:Single bond: 1 sigma
Double bond: 1 sigma 1 pi
Triple bond: 1 sigma 2 pi
Quadruple bond: 1 sigma 2 pi 1 delta
What exactly is a delta bond? Have we gone over this?
I think a delta bond occurs when all four lobes of a d orbitals interact with one another
- Fri Nov 13, 2020 10:46 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity difference
- Replies: 12
- Views: 449
Re: Electronegativity difference
I think it could either be ionic or covalentVeronica Macias 3C wrote:Also, what type of bonds are atoms with an electronegativity difference between 1.5 and 2?
- Fri Nov 13, 2020 10:40 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration Exceptions?
- Replies: 5
- Views: 310
Re: Electron Configuration Exceptions?
The 4s subshell is filled before the 3d subshell because the 4s orbital has a lower energy level than the 3d orbital. In terms of writing out the electron configuration, you write the subshell with the lower quantum number first. That is why 3d comes before 4s when written.
- Fri Nov 13, 2020 10:32 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Valence electron numbers
- Replies: 6
- Views: 325
Re: Valence electron numbers
Julianna_flores3L wrote:I think that the p orbital that you are talking about has to do more with quantum numbers rather than valence electrons? Correct me if I am mistaken.
Yeah, I agree. I think this has to do more with the shape and the wave function, but I'm not positive
- Fri Nov 13, 2020 10:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: Nomenclature
- Replies: 6
- Views: 246
Re: Nomenclature
Is it safe to assume that most of the time on exams the molecular formula will be given along with the name of the molecule?
- Sun Nov 08, 2020 9:32 pm
- Forum: Lewis Structures
- Topic: Expanded octets in Lewis diagrams
- Replies: 1
- Views: 99
Re: Expanded octets in Lewis diagrams
My guess is we will have to draw some structures with expanded octets because Dr. Lavelle took the time to go through an example in one of the lectures. As far as being able to tell whether an element has an expanded octet, I don't really know. The example that Dr. Lavelle used was PCl5, which had f...
- Sun Nov 08, 2020 9:24 pm
- Forum: Ionic & Covalent Bonds
- Topic: formal charge
- Replies: 8
- Views: 294
Re: formal charge
Hi! From what I understood from the lectures I think formal charge is used to mainly keep track of the charge of atoms and molecules while drawing the lewis structures. From there I think you can use the charge to predict things about the atoms and molecules, such as reactivity.
- Sun Nov 08, 2020 9:18 pm
- Forum: Trends in The Periodic Table
- Topic: Arranging Elements by Electron Affinity
- Replies: 2
- Views: 156
Re: Arranging Elements by Electron Affinity
The most energy is absorbed by gaining an electron for Kr because it is a noble gas and already has a eight valence e-
- Sun Nov 08, 2020 9:11 pm
- Forum: Octet Exceptions
- Topic: Expanded Octets
- Replies: 6
- Views: 178
Re: Expanded Octets
Some elements, like sulfur and chlorine, can be expanded because they utilize d-orbitals from the third energy level and on
- Sun Nov 01, 2020 2:10 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Arranging Elements by Electron Affinity
- Replies: 6
- Views: 289
Re: Arranging Elements by Electron Affinity
I think they release energy because they become more stable once they have attained the electron(s) needed, and stable states have less energy that unstable states. Feel free to correct me if I'm wrong :)
- Sun Nov 01, 2020 1:56 pm
- Forum: Properties of Electrons
- Topic: Sapling HW #1
- Replies: 6
- Views: 271
Re: Sapling HW #1
When talking about the wavelength and frequency, it is referring to one photon because all of the photons in the pulse have the same wavelength and frequency. The energy is multiplied by 100 because there are 100 photons with the same wavelength and frequency. If you look at the equation, E=hv, freq...
- Sun Nov 01, 2020 1:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Participation Points [ENDORSED]
- Replies: 62
- Views: 3745
Re: Participation Points [ENDORSED]
Javier Perez M 2J wrote:By what day do we have to post every week?
Sunday by midnight
- Mon Oct 26, 2020 10:18 pm
- Forum: Student Social/Study Group
- Topic: Midterm
- Replies: 5
- Views: 289
Re: Midterm
I'm pretty sure none of the problems assigned from section 1.D are apply to this midterm.
- Mon Oct 26, 2020 10:08 pm
- Forum: Photoelectric Effect
- Topic: Moles of atoms/photons
- Replies: 3
- Views: 122
Re: Moles of atoms/photons
It depends on the problem, like what you're given and what you're converting to.
- Sat Oct 24, 2020 7:42 pm
- Forum: Balancing Chemical Reactions
- Topic: combustion
- Replies: 4
- Views: 411
Re: combustion
We include the delta sign because it represents the heat that is supplied to carry out the reaction.
- Sat Oct 24, 2020 6:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Questions on midterm
- Replies: 7
- Views: 254
Re: Questions on midterm
I'm pretty sure my TA said between 20-30 question, and they will be multiple choice.
- Sat Oct 24, 2020 6:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Calculator
- Replies: 3
- Views: 123
Re: Calculator
Yeah you can use any type of calculator. It doesn't have to be a scientific one.
- Sat Oct 24, 2020 6:29 pm
- Forum: Properties of Electrons
- Topic: Textbook problem Quantum World 1A 15
- Replies: 3
- Views: 229
Re: Textbook problem Quantum World 1A 15
So first off you want to use the equation c=wavelength*frequency and solve for the frequency of the 102.6 nm wave. Then, you would plug this into Ryberg's equation and use that to solve for n2. Hope this helps :)
- Fri Oct 23, 2020 11:14 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Outline question heisenberg indeterminancy
- Replies: 3
- Views: 169
Re: Outline question heisenberg indeterminancy
Yeah, you are right. Delta v is 10 m/s. This is one of the errors in the solution manual.
- Sat Oct 17, 2020 9:18 pm
- Forum: Einstein Equation
- Topic: Changing sign from neg to pos in E=hv
- Replies: 4
- Views: 171
Re: Changing sign from neg to pos in E=hv
Is the energy released from a photon always positive then? I'm pretty sure because the only reason the electron has a "negative" energy is due to to it coming back down from the reference state where the energy is zero. The photon would have a positive energy because it either has energy ...
- Sat Oct 17, 2020 9:13 pm
- Forum: Einstein Equation
- Topic: Changing sign from neg to pos in E=hv
- Replies: 4
- Views: 171
Re: Changing sign from neg to pos in E=hv
I'm not entirely sure about this but I believe that the energy of the photon given off is the negative of the change in energy of the electron when it drops to a lower energy level. Since the change in energy of the electron is negative, the energy of the photon would have the opposite sign, hence ...
- Fri Oct 16, 2020 9:01 pm
- Forum: Properties of Electrons
- Topic: Sapling Homework
- Replies: 4
- Views: 240
Re: Sapling Homework
Are the questions he's adding still apart of the quantum unit? Does this mean we will be in this unit until the end of week 4?
- Fri Oct 16, 2020 8:43 pm
- Forum: Balancing Chemical Reactions
- Topic: L35
- Replies: 3
- Views: 199
Re: L35
Yeah, it's an error. On Professor Lavelle's website there is a link that has all the solution manual errors and the corrections.
- Fri Oct 16, 2020 7:17 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Conservation of energy
- Replies: 4
- Views: 158
Re: Conservation of energy
Hi, I'm not sure I understand your question completely, but I'm pretty sure an electron will always start at the energy level of n=1. For the electron to jump to a greater energy level, it must be excited. For the example you are talking about, I think that they just implied that the electron starte...
- Wed Oct 07, 2020 9:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Learning Outcome Outlines
- Replies: 5
- Views: 98
Re: Learning Outcome Outlines
Are the three videos before the one about the photoelectric effect supposed to be review for the quantum unit?
- Wed Oct 07, 2020 9:03 pm
- Forum: Limiting Reactant Calculations
- Topic: Sapling HW Week 1 Question #10
- Replies: 8
- Views: 208
Re: Sapling HW Week 1 Question #10
Hey, I was also confused, but I found this post where a lot people left explanations. viewtopic.php?f=13&t=63002
- Wed Oct 07, 2020 6:40 pm
- Forum: SI Units, Unit Conversions
- Topic: SI Units
- Replies: 13
- Views: 335
Re: SI Units
I agree with Justin. I think if the question wanted the answer in units different from SI units it would state that.
- Wed Oct 07, 2020 5:28 pm
- Forum: Student Social/Study Group
- Topic: Group Me Link
- Replies: 5
- Views: 299
Re: Group Me Link
I don't know if anyone from Discussion 3K still needs this, but here is the link for the GroupMe. https://groupme.com/join_group/63092382/qDDFwhPF
- Wed Oct 07, 2020 5:14 pm
- Forum: Limiting Reactant Calculations
- Topic: Textbook Question M19)
- Replies: 5
- Views: 259
Re: Textbook Question M19)
The textbook problems aren't being collected. You can find them on Professor Lavelle's website under "Learning Outcomes" in the outlines, and this week's problems would be in "Outline 1: Review of Chemical & Physical Principles."