I believe we only need to know this for ideal gasses, and the values are given on the equation sheet, but I obviously can't say for sure
Hope this helps!
Search found 100 matches
- Sat Mar 13, 2021 7:13 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: R constant and shape of molecules
- Replies: 2
- Views: 293
- Sat Mar 13, 2021 7:09 pm
- Forum: Biological Examples
- Topic: Textbook 7.9
- Replies: 1
- Views: 522
Re: Textbook 7.9
What part do you not understand? Iĺl try to give a somewhat broad explanation but lmk if you need help with a specific part. Basically, it is saying that for the first proposed mechanism, since water is not present in the bottleneck step, water's concentration will not affect the rate at which the r...
- Sat Mar 13, 2021 7:05 pm
- Forum: Student Social/Study Group
- Topic: Equations for the Final
- Replies: 5
- Views: 340
Re: Equations for the Final
I think you should be good just knowing the equations on the sheet, the most important thing is remembering how to use each one! If you are struggling with this, I would recommend going through some homework problems just using the equations sheet so as to make sure that you can pick out the correct...
- Sat Mar 13, 2021 6:57 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Drawing Reaction Profiles
- Replies: 1
- Views: 197
Re: Drawing Reaction Profiles
The only way I know at our level to figure this out is to count the number of bonds broken, and assume that the more ordered phase would have the least bonds broken. However, in general, the intermediate steps will always be higher than the reactants or the products, otherwise, the reaction would no...
- Sat Mar 13, 2021 6:53 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Textbook Problem 7E.3
- Replies: 2
- Views: 172
Re: Textbook Problem 7E.3
Hi! You are going to need to use the Arrhenius equation ( k = A e^{\frac{-E_{a}}{RT}} ) to determine k for the original pathway, then for the catalyzed pathway. k will be exponentially higher for the catalyzed pathway due to the change in activation energy, so expect a large ratio as you will be fin...
- Sun Mar 07, 2021 11:41 pm
- Forum: Balancing Redox Reactions
- Topic: Redox Tips
- Replies: 5
- Views: 356
- Sun Mar 07, 2021 11:40 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Determining catalyst in mechanism
- Replies: 7
- Views: 451
Re: Determining catalyst in mechanism
You can tell because you will see it in the steps of the reaction, but not in the overall chemical equation. I suppose that you could see that the catalyst was not being modified in the steps of the reaction? But I would be wary of using that method and I doubt you will be asked to do so.
- Sun Mar 07, 2021 11:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 12
- Views: 536
Re: Salt Bridges
Salt bridges connect anode and cathode and help keep reduction and oxidation solution from building up positive/negative charges, essentially keeps the cell working I really like what you said here, I just felt like it would be helpful to add that they move ions from one side of the cell to the oth...
- Sun Mar 07, 2021 11:35 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Determining Anode vs Cathode
- Replies: 23
- Views: 872
Re: Determining Anode vs Cathode
The best way I have learned to do this is to use the mnemonic “Red Cat An Ox”, which tells me that oxidation occurs at the anode and reduction occurs at the cathode. Since the reaction at the anode is the source of electrons for the current, the anode is the negative terminal for the galvanic cell.
- Sun Mar 07, 2021 11:32 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Electrochemistry
- Replies: 9
- Views: 597
Re: Electrochemistry
Hi Karen, the only equations I can find that we are responsible for are as follows Nernst Equation Ecell = Estd - ((RT)/(nF)) ln([P]/[R]) (This can be written many ways, but this is the most universal) Nernst Precursor Delta(G) = -nFE and then some more conceptual stuff like redox balancing, cathode...
- Sun Feb 28, 2021 11:15 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling 10
- Replies: 9
- Views: 423
Re: Sapling 10
Nope, you have to look up the table in this case (as far as I know), especially for transition metals, patterns are spotty in this area.
- Sun Feb 28, 2021 11:14 pm
- Forum: Balancing Redox Reactions
- Topic: Full molecule in half reactions?
- Replies: 8
- Views: 468
Re: Full molecule in half reactions?
You should write the entire molecule, as we kind of treat it as a unit when performing these kinds of calculations
- Sun Feb 28, 2021 11:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in ∆G = -nFE
- Replies: 80
- Views: 3810
Re: n in ∆G = -nFE
I would just look at the number of moles of electrons that are transferred in the reaction that you are looking at, that is what n refers to here
- Mon Feb 22, 2021 1:16 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U in Isothermal Systems
- Replies: 7
- Views: 478
Re: Delta U in Isothermal Systems
Yup! A good way to think about this for me is that any energy gained through heat must be equal to the amount lost through work (or vice versa) for the temperature to remain constant (or that it would have to go somewhere else like in a phase change). Thus, if q=-w, ∆U = q + (-q) = 0 (And vice versa...
- Mon Feb 22, 2021 1:12 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isobaric
- Replies: 20
- Views: 1122
Re: isobaric
Isobaric is just another word for constant pressure. This means that you are likely dealing with an irreversible expansion, so w = -P∆V, and that heat (q) will equal enthalpy (∆H).
Hope this helps!
Colm
Hope this helps!
Colm
- Mon Feb 22, 2021 1:09 am
- Forum: Student Social/Study Group
- Topic: Students Who Have a Job
- Replies: 103
- Views: 8973
Re: Students Who Have a Job
I work part-time as an EMT and it can be really tough to manage with school. It is hard to come back from a shift and get work done, so I usually try to plan my workload around working, but I obviously can't do this for every night I work. Sometimes I will bring reading into work, as I usually have ...
- Mon Feb 22, 2021 1:06 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: q/T
- Replies: 1
- Views: 260
Re: q/T
As per this page on ChemLibreTexts , \Delta S = \frac{q}{T} for processes occuring at a constant temperature not a constant Internal energy. I think that this is just a condition of the equation given, as no rationale is listed but it would make sense that work could change in this type of scenario ...
- Mon Feb 22, 2021 1:00 am
- Forum: Student Social/Study Group
- Topic: Chem 14B Final
- Replies: 86
- Views: 5083
Re: Chem 14B Final
From what I remember from last quarter, the final consisted of questions very similar to the midterms in both difficulty and style. I agree with the others that the best practice is to work through all of the given textbook problems and try to attend as many UA Sections as you can. Consistency is ke...
- Wed Feb 10, 2021 12:59 am
- Forum: Student Social/Study Group
- Topic: Midterm 2 study tips
- Replies: 26
- Views: 1220
Re: Midterm 2 study tips
I think that doing textbook problems helps with making sure you know how to work the equations quickly and effectively, but for understanding the concepts nothing has been as good for me as talking it out with a peer. Find a study buddy and work through some problems together!!!
- Wed Feb 10, 2021 12:00 am
- Forum: Calculating Work of Expansion
- Topic: How to know which equations to use?
- Replies: 11
- Views: 737
Re: How to know which equations to use?
For me the best place to start is always the units. If I can look at the units in the question and the units required of the answer, usually I can determine what equations will manipulate those units in such a way as to take me to the right answer. The key to this method is memorizing the units of e...
- Tue Feb 09, 2021 11:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Textbook Problem 4.7: Standard Enthalpies of Formation
- Replies: 3
- Views: 287
Re: Textbook Problem 4.7: Standard Enthalpies of Formation
285.83 kJ/mol is the standard enthalpy of formation you want, not -241.82. Your equation looks right, I think you just accidentally had the wrong value.
Hope this helps!
Colm
Hope this helps!
Colm
- Tue Feb 09, 2021 11:28 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible Reactions
- Replies: 4
- Views: 278
Re: Reversible Reactions
The way that I think about it is that in a reversible process, the energy lost to heat is minimized and the energy that goes into work is maximized. Since the two systems are in constant quasiequilibrium. Since this is impossible in the physical world (as it would take infinite time), no process is ...
- Tue Feb 09, 2021 11:07 pm
- Forum: Calculating Work of Expansion
- Topic: Extra practice problems/videos
- Replies: 13
- Views: 704
Re: Extra practice problems/videos
I cannot recommend the organic chemistry tutor enough. https://www.youtube.com/watch?v=NyOYW07-L5g&list=PL0o_zxa4K1BWziAvOKdqsMFSB_MyyLAqS&index=110 https://www.youtube.com/watch?v=GL3gCBUua4c&list=PL0o_zxa4K1BWziAvOKdqsMFSB_MyyLAqS&index=111 https://www.youtube.com/watch?v=E7s-hIoy...
- Sun Feb 07, 2021 11:59 pm
- Forum: Calculating Work of Expansion
- Topic: Extra practice problems/videos
- Replies: 13
- Views: 704
Re: Extra practice problems/videos
I cannot recommend the organic chemistry tutor enough. https://www.youtube.com/watch?v=NyOYW07-L5g&list=PL0o_zxa4K1BWziAvOKdqsMFSB_MyyLAqS&index=110 https://www.youtube.com/watch?v=GL3gCBUua4c&list=PL0o_zxa4K1BWziAvOKdqsMFSB_MyyLAqS&index=111 https://www.youtube.com/watch?v=E7s-hIoyN...
- Sun Feb 07, 2021 11:50 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: sapling 19
- Replies: 1
- Views: 140
Re: sapling 19
First calculate the calorimetry constant of the calorimeter: (1.05kJ/2.19C)/0.700L = ? kJ/C*L This lets you know how much energy it takes to raise a liter of solution in the calorimeter by 1 C. Then you can do essentially the same thing in reverse to see how much heat the reaction released. Hope thi...
- Sun Feb 07, 2021 11:38 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Different R Constants
- Replies: 14
- Views: 685
Re: Different R Constants
Depends on what you are trying to solve! The best practice is probably to track the units for the problem you are trying to solve, but in general, if you want volume use 0.08, and if you want energy use 8.13.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Feb 07, 2021 11:34 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Liquids and Solids
- Replies: 7
- Views: 319
Re: Liquids and Solids
The thing is, they are changing but ever so slightly. At the level of precision we are working with, these changes will not be a factor in our calculations.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Feb 07, 2021 11:31 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Explaining Enthalpies
- Replies: 7
- Views: 423
Re: Explaining Enthalpies
Heat energy = energy that can cause a change in temperature
Work energy = energy that can do work to change a system's physical properties, such as pressure or volume. While we have only calculated this for gasses, it is present for solids and liquids as well, just imperceptibly.
Work energy = energy that can do work to change a system's physical properties, such as pressure or volume. While we have only calculated this for gasses, it is present for solids and liquids as well, just imperceptibly.
- Sun Feb 07, 2021 11:28 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Explaining Enthalpies
- Replies: 7
- Views: 423
Re: Explaining Enthalpies
Enthalpy is the amount of heat-energy present in a system, as well as the work-energy available in the system. Thus, H = U + PV. At constant pressure, since the work-energy will not change, the change in enthalpy will be equal to the heat energy change of the system.
- Sun Jan 31, 2021 10:34 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Work
- Replies: 7
- Views: 263
Re: Work
It is kind of representative of our perspective. From our perspective, the "system" is the gas being manipulated, and the "surroundings" are the container that it is being manipulated in. Since energy is being transferred from the system to the surroundings, we say it is being lo...
- Sun Jan 31, 2021 10:22 pm
- Forum: Calculating Work of Expansion
- Topic: Sapling week 4 #14
- Replies: 1
- Views: 132
Re: Sapling week 4 #14
Path A is isothermal reversible expansion, meaning that In the reversible process, so the pressure of the surroundings is always going to be less than the pressure of the system, by an infinitesimally small quantity. Thus, W = nRT ln(V1/V2). As long as you use the correct constants, this process sho...
- Sun Jan 31, 2021 10:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: steam causing burns
- Replies: 40
- Views: 1212
Re: steam causing burns
Heat energy causes burns, not just temperature Steam has to contain enough heat energy to raise the speed of the H 2 O molecules to reach the temperature of the gas, as well as to break the intermolecular interactions holding the liquid H 2 O molecules together. Thus, 100 o C liquid H 2 O molecules ...
- Sun Jan 31, 2021 9:50 pm
- Forum: Ideal Gases
- Topic: Kp?
- Replies: 30
- Views: 920
Re: Kp?
Just a quick note as to why:
For at the level of precision we will be dealing with solids and liquids are incompressible. Thus, a change in PRESSure cannot affect the concentration of such substances.
Hope this helps!
Colm
For at the level of precision we will be dealing with solids and liquids are incompressible. Thus, a change in PRESSure cannot affect the concentration of such substances.
Hope this helps!
Colm
- Mon Jan 25, 2021 4:42 pm
- Forum: Significant Figures
- Topic: Can subtracting reduce the number of Significant Figures a number has?
- Replies: 4
- Views: 3685
Can subtracting reduce the number of Significant Figures a number has?
Say I have to subtract then divide: 0.7552g - 0.7241g = 0.0311 g <- Here we keep 4 decimal places because we are subtracting. For my next step, I would like to divide by 768.95 g/mol Will my rounded answer be 4.044*10^-5 mol or 4.04*10^-5 mol? The question boils down to can subtraction reduce the ac...
- Mon Jan 25, 2021 12:01 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Weak acid vs strong acid
- Replies: 4
- Views: 289
Re: Weak acid vs strong acid
Strong acids are those found here, they will dissociate completely in water, all other acids and bases will require a Ka/Kb calculation to find their h30+ concentration
- Sun Jan 24, 2021 11:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka and pH calculation
- Replies: 4
- Views: 198
Re: Ka and pH calculation
Use the Ka to solve the dissociation equation (Ka=[CB][H30+]/[A]) to find the [H30+] concentration, then take the -log of that to find the pH!
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 24, 2021 11:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Definition of a monoprotic acid
- Replies: 3
- Views: 206
Re: Definition of a monoprotic acid
A Monoprotic acid is one that will dissociate into a single proton and a conjugate base when it dissociates. It would change a reaction by increasing the pH.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 24, 2021 11:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy Reactions
- Replies: 13
- Views: 396
Re: Enthalpy Reactions
I bet we will have to consider phase changes, especially since there were homework problems that included them.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 24, 2021 11:51 pm
- Forum: Phase Changes & Related Calculations
- Topic: standard reaction enthalpies
- Replies: 4
- Views: 286
Re: standard reaction enthalpies
It is my understanding that standard reaction enthalpies like those found in the table here show how much heat energy would be required to form a given reactant from its constituent parts in their standard states.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 17, 2021 9:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: dilution/pH textbook problem
- Replies: 1
- Views: 73
Re: dilution/pH textbook problem
You should be able to use the [OH-] you found in (i) times the dilution factor (think 5 -> 500) to find the [OH-] of the original solution.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 17, 2021 9:15 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #6
- Replies: 10
- Views: 377
Re: Sapling Week 1 #6
Hi there,
What is your question on this topic? Just so you know, you should ask a specific question about a problem, I'm not sure if you get credit for just generally asking for help.
I hope this doesn't come off as rude, just letting you know so you can get your points.
All the best,
Colm
What is your question on this topic? Just so you know, you should ask a specific question about a problem, I'm not sure if you get credit for just generally asking for help.
I hope this doesn't come off as rude, just letting you know so you can get your points.
All the best,
Colm
- Sun Jan 17, 2021 9:13 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: changing volume by adding more solid reactants.
- Replies: 3
- Views: 215
Re: changing volume by adding more solid reactants.
I think that this question may be beyond the scope of this class, but I would imagine that if you were in the situation you described, and you were dealing with gaseous reactants, for optimal accuracy you would want to proceed with a correction for the new pressures after the addition of an incompre...
- Sun Jan 17, 2021 9:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What makes a weak acid?
- Replies: 11
- Views: 278
Re: What makes a weak acid?
Ok, thanks for the help Sara! I'll make a quizlet :(
- Sun Jan 17, 2021 9:06 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 2 Sapling Hw #2
- Replies: 8
- Views: 416
Re: Week 2 Sapling Hw #2
The percent ionization will be the amount of charged particles at equilibrium (for a monoprotic acid, this is just the H30+ concentration) divided by the initial concentration (in this case 0.00214M) of the acid. This will tell you what percentage of the acid has dissociated to form charged species....
- Sun Jan 17, 2021 9:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What makes a weak acid?
- Replies: 11
- Views: 278
What makes a weak acid?
Hi all,
On exams, will we be specifically told when we are dealing with a "weak" acid or base? I have a hard time with memorization, so I dont want to memorize the strong acids table unless I need to.
Thanks in advance!
Colm
On exams, will we be specifically told when we are dealing with a "weak" acid or base? I have a hard time with memorization, so I dont want to memorize the strong acids table unless I need to.
Thanks in advance!
Colm
- Sun Jan 10, 2021 7:58 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: reaction quotient
- Replies: 6
- Views: 283
Re: reaction quotient
Reaction quotient tells us the relative amounts of reactants and products at a given time in the progress of the reaction.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Jan 10, 2021 7:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q and K
- Replies: 8
- Views: 361
Re: Q and K
Q describes a reaction in progress, K is Q when the reaction is at equilibrium. So for a given reaction, we can compare Q to K to see how that reaction will proceed (Q>K: More reactants will be created than products, Q<K: More products will be created than reactants) unless Q=K, in which case the tw...
- Sun Jan 10, 2021 7:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K values
- Replies: 4
- Views: 210
Re: K values
Can you clarify your question?[code][/code]
- Sun Jan 10, 2021 7:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentrations
- Replies: 9
- Views: 449
Re: Concentrations
We will have to be given the concentrations of the P and the R. Then the problem will focus on manipulating the given concentrations to find an unknown concentration.
Does that make sense?
All the best,
Colm
Does that make sense?
All the best,
Colm
- Sun Jan 10, 2021 7:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling HW 1 Question 2
- Replies: 8
- Views: 285
Re: Sapling HW 1 Question 2
Just to clarify: It is perfectly fine to use the actual molar amounts in the ICE table, as the volume of the container will not change between steps of the reaction. When you then plug the values from the ICE table into the K equation, you need to make the conversion to concentration. This is becaus...
- Thu Dec 17, 2020 12:16 am
- Forum: Lewis Acids & Bases
- Topic: Acid and Base theories
- Replies: 2
- Views: 212
Re: Acid and Base theories
They are just looking at different parts of the acidic process. Acids and bases are just substances that become charged in water. The Bronstead-Lowry definition simply calls substances acids or bases based on how their protons behave while the Lewis definition is about how their electrons behave. Th...
- Thu Dec 17, 2020 12:06 am
- Forum: Amphoteric Compounds
- Topic: Amphoteric and Amphiprotic
- Replies: 2
- Views: 353
Re: Amphoteric and Amphiprotic
Amphoteric and Amphiprotic essentially mean the same thing, Amphiprotic is just specific to the Bronstead Acid Definition. While Amphiphoteric means a compound that can act as either an acid or a base depending on its milieu, a definition that applies to all ways to describe acids, Apmhiprotic speci...
- Thu Dec 17, 2020 12:01 am
- Forum: Air Pollution & Acid Rain
- Topic: ocean acidification
- Replies: 3
- Views: 336
Re: ocean acidification
Nope, these are different chemical processes. As I understand it, Ocean Acidification is a phenomenon driven by the increased atmospheric carbon dioxide we are producing while acid rain comes from sulfur and nitrogen oxides released into the air. Ocean acidification comes from the high atmospheric C...
- Wed Dec 16, 2020 11:45 pm
- Forum: Student Social/Study Group
- Topic: Participation
- Replies: 56
- Views: 2712
Re: Participation
Where are our participation points? I checked both ccle and ucla and I didn't see them To find them on MyUCLA: ⋅ Click "Classes" in the navigation bar, and follow the link "Exam and Homework Grades" under the category "Grades and Transcripts". ⋅ On ...
- Wed Dec 16, 2020 11:35 pm
- Forum: General Science Questions
- Topic: Study Habits
- Replies: 19
- Views: 1327
Re: Study Habits
I really focused on textbook problems. I know that they can get a bit tedious, but I really think that practicing is the best way to learn this stuff. Especially with the heavy emphasis on VSEPR and Lewis Structures, you have to build muscle memory so that the answers will come quickly and you will ...
- Mon Dec 07, 2020 1:12 am
- Forum: Student Social/Study Group
- Topic: 14BL waitlist
- Replies: 1
- Views: 131
Re: 14BL waitlist
You should still get the class but get switched to another discussion section, especially since Lavelle is known for offering all of the students on his waitlist into the class. Honestly, as long as you can get to the ccle page, you should be fine.
Hope this helps,
Colm
Hope this helps,
Colm
- Mon Dec 07, 2020 1:10 am
- Forum: Resonance Structures
- Topic: Resonance Structures and Stability
- Replies: 4
- Views: 283
Re: Resonance Structures and Stability
All of the resonance structures are not equivalent because one of them will be most favored by the system. One way to think about this is with lewis structure formal charge. The lowest formal charge system will be favored over the others, even though they will all be a part of the explanation of tha...
- Mon Dec 07, 2020 1:03 am
- Forum: Naming
- Topic: coordination compounds with aqua
- Replies: 12
- Views: 680
Re: coordination compounds with aqua
https://opentextbc.ca/chemistry/chapter/19-2-coordination-chemistry-of-transition-metals/ This Canadian textbook uses H 2 O, but everyone else above also makes a good point as Oxygen would be the atom actually bonded to the Cobalt (In the [Co(H 2 O) 6 ] 2+ example shown here: https://opentextbc.ca/...
- Mon Dec 07, 2020 12:56 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Chart
- Replies: 8
- Views: 620
Re: VSEPR Chart
I managed to find the chart and a solid quizlet similar to the one detailed above! I hope these help whoever comes across this next. Just click on the Q logo to get linked to the quizlet (https://quizlet.com/209997502/vespr-flash-cards/). https://www.sigmaaldrich.com/content/dam/sigma-aldrich/articl...
- Mon Dec 07, 2020 12:48 am
- Forum: Sigma & Pi Bonds
- Topic: Pi and Sigma Bonds Positions
- Replies: 2
- Views: 769
Re: Pi and Sigma Bonds Positions
I have also found this image quite useful, it was what let me eventually understand this topic. https://i.imgur.com/ThuMN1j.jpg It is definitely a model representation, however, you can see that while the sigma bond occurs on the line between the two double-bonded nuclei of the molecule, the pi bond...
- Sun Nov 29, 2020 8:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 252
Re: Bond Angles
Those are the only factors I consider and I did OK on the sapling problems. I would make sure you had all the shape angles memorized as they are somewhat counterintuitive for me.
- Sun Nov 29, 2020 8:34 pm
- Forum: Sigma & Pi Bonds
- Topic: Rotation
- Replies: 16
- Views: 858
Re: Rotation
Yes I would say that that makes sense
- Sun Nov 29, 2020 8:33 pm
- Forum: Sigma & Pi Bonds
- Topic: Pi vs Delocalized Pi Bonds
- Replies: 3
- Views: 124
Re: Pi vs Delocalized Pi Bonds
A delocalized pi bond is a resonant pi bond, basically, if you could write a resonant structure where a double or triple bond would take the place of a single bond, that would represent a delocalized pi bond.
Hope this helps!
Colm
Hope this helps!
Colm
- Sun Nov 29, 2020 8:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: ions
- Replies: 8
- Views: 385
Re: ions
Hi Augustina, hope your first year of college is going well! If atoms have a negative charge, they should repel any lone pair/bonded electrons around them while if they had a positive charge they would attract these regions of high electron density. This should also hold true for dipoles and other p...
- Sun Nov 29, 2020 8:19 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration for Transition Metals
- Replies: 3
- Views: 342
Re: Electron Configuration for Transition Metals
The key things for me are when you count up, you start with the s orbitals and when you count down, like with ions, those are the first to go. You also need to remember the exceptions to this general rule with chromium (3d5 4s1) and copper (3d10 4s1) both moving an s orbital electron to the d orbita...
- Sun Nov 22, 2020 10:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 2 Scores
- Replies: 28
- Views: 1295
Re: Midterm 2 Scores
I’m not trying to rush him, just speculating on when we might have our scores back, I know a lot of people stress about not knowing how they did and not knowing when they will find out
- Sun Nov 22, 2020 10:00 pm
- Forum: Octet Exceptions
- Topic: Textbook 2C7 Iodine
- Replies: 2
- Views: 250
Re: Textbook 2C7 Iodine
I just want to add that for most molecules it would be good to make use of the octet rule first, iodine is kind of an exception to the standard operating procedure
- Sun Nov 22, 2020 9:49 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Hydrogen Bonding Confusion
- Replies: 3
- Views: 292
Re: Hydrogen Bonding Confusion
I think it can also cause conformational changes in large molecules, like I know for a fact that some proteins shapes depend on hydrogen bonding, and it is the breakage of these hydrogen bonds that leads to protein denaturation at high temperature.
- Sun Nov 22, 2020 9:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Thanksgiving
- Replies: 26
- Views: 1146
Re: Thanksgiving
I imagine we will still have a lecture but I would wait for word from up top before jumping to conclusions.
- Sun Nov 22, 2020 9:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 2 Scores
- Replies: 28
- Views: 1295
Re: Midterm 2 Scores
There was also a problem with the last midterm that extended the grading time iirc, so I think it might be faster this time around.
- Sun Nov 15, 2020 11:47 pm
- Forum: Ionic & Covalent Bonds
- Topic: Workshop Hydrogen Bonding Question
- Replies: 4
- Views: 666
Re: Workshop Hydrogen Bonding Question
Yes, this compound can serve as the lone pair side of hydrogen bonding, but not as the hydrogen-attached-to-electronegative-atom side of it.
- Sun Nov 15, 2020 11:44 pm
- Forum: Lewis Structures
- Topic: Coordinate Covalent Bond vs Lewis Acid/Base
- Replies: 2
- Views: 77
Re: Coordinate Covalent Bond vs Lewis Acid/Base
I think this is a case of set subset interaction, where all coordinate covalent bonding is Lewis Acid-Base bonding but not vice versa, or I could be confised. This is a bit of a tricky topic for me but I thought I would throw in my two cents. Please correct me if I am mistaken!
- Sun Nov 15, 2020 11:42 pm
- Forum: Resonance Structures
- Topic: Maximum
- Replies: 3
- Views: 167
Re: Maximum
Google is a good shortcut for the real world, but unfortunately, it won't help you on the test. If you are given the bond lengths though, we can see what resonance structures will be favored based on experimental evidence.
- Sun Nov 15, 2020 11:40 pm
- Forum: Bond Lengths & Energies
- Topic: Bonds and Accepting Electrons
- Replies: 2
- Views: 155
Re: Bonds and Accepting Electrons
Just to add on a bit I believe it has to be a double bond due to the magnitude of the dipole involved. A polar double bond will have more of a charge disparity than a polar single bond, and therefore more of an ability to accept electrons.
- Sun Nov 15, 2020 11:32 pm
- Forum: Bond Lengths & Energies
- Topic: Question 3 F.15
- Replies: 1
- Views: 101
Re: Question 3 F.15
The boiling points of these molecules will be different based on the strength of the intermolecular interactions that they experience. Their relative molecular weight also plays a part as compounds with heavier molar masses will take more energy to vaporize than lighter ones. CF 2 H 2 does not have ...
- Sun Nov 08, 2020 11:55 pm
- Forum: Electronegativity
- Topic: Fluorine and Helium
- Replies: 6
- Views: 190
Re: Fluorine and Helium
I think so, especially since Noble gasses are the exception to so many rules. But there is also some argument that He should be next to H I think? Like this is one of the arguments for why it belongs on the left side of the table iirc.
- Sun Nov 08, 2020 11:53 pm
- Forum: Resonance Structures
- Topic: formal charge
- Replies: 3
- Views: 100
Re: formal charge
I'm pretty sure it is because the form with the lowest formal charge would also be the most stable! So it is naturally going to be favored due to the 2nd law of thermodynamics. Hope that helps!
- Sun Nov 08, 2020 11:51 pm
- Forum: Lewis Structures
- Topic: Sapling Week 5-6 HW Question 6
- Replies: 7
- Views: 306
Re: Sapling Week 5-6 HW Question 6
Yeah, I'm pretty sure CO2 would have a resonant structure with one C=O bond and one C-O bond.
Just for a bit more clarity.
Just for a bit more clarity.
- Thu Nov 05, 2020 1:22 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 1 Review
- Replies: 7
- Views: 180
Midterm 1 Review
Hi All, As the scores are now in CCLE, I was wondering if there will be any way for us to review our tests and see what we did wrong. I'd like to learn from my mistakes, but I understand that the online environment does not always permit this. Perhaps we could schedule a meeting with our TAs 1on1 to...
- Thu Nov 05, 2020 1:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 1
- Replies: 9
- Views: 343
Re: Midterm 1
They are in! Go and check if you dare.
- Sun Nov 01, 2020 7:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Curve on Midterm
- Replies: 9
- Views: 385
Re: Curve on Midterm
My TA told us that the test will be graded on a straight scale with partial credit awarded for some wrong answers on certain questions to make up for the fact that they can't see our thought process. In another thread, someone mentioned that we should expect to have our scores in hand at the end of ...
- Sun Nov 01, 2020 7:42 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 2
- Views: 147
Re: Electron Affinity
Hi Lily, could you clarify your question a little bit? I'll do my best with what you have but I'm a touch unsure what I am answering. Electron affinity won't itself determine whether energy is released or absorbed, that has to do with what is happening to the electron. We would need to add energy to...
- Sun Nov 01, 2020 6:58 pm
- Forum: Trends in The Periodic Table
- Topic: Sapling question 24
- Replies: 3
- Views: 377
Re: Sapling question 24
Effective nuclear charge refers to the net positive charge an electron experiences in an atom. Since the only positive component of an atom of matter is a proton, and a fluorine atom would have 1 more proton than an oxygen atom, a fluorine atom would have more total positive charge to distribute amo...
- Mon Oct 26, 2020 11:29 pm
- Forum: DeBroglie Equation
- Topic: Sapling Week 2 HW_problem #22
- Replies: 7
- Views: 375
Re: Sapling Week 2 HW_problem #22
^^for the person who asked for my solution, sapling said this was correct
- Mon Oct 26, 2020 11:28 pm
- Forum: DeBroglie Equation
- Topic: Sapling Week 2 HW_problem #22
- Replies: 7
- Views: 375
Re: Sapling Week 2 HW_problem #22
Constants: λ=0.0197nm=(1.97*10^-11)m, h=(6.63*10^-34) J*s, m(electron)=(9.11*10^-31) kg λ=h/mv -> v=h/mλ -> v=(6.63*10^-34)/((1.97*10^-11)(9.11*10^-31))=(3.69427248464*10^7)m/s Ek = 1/2(m)(v)^2 -> Ek=(0.5)(9.11*10^-31)((3.69427248464*10^7)^2)=6.2165042e-16 J Then you just convert J to eV (6.2165042*...
- Sun Oct 25, 2020 11:50 pm
- Forum: DeBroglie Equation
- Topic: Any tips for using a TI-83 Calculator?
- Replies: 4
- Views: 309
Re: Any tips for using a TI-83 Calculator?
I think a good tip is to use the function buttons. It is just a lot easier for me to keep track of like fractions and stuff when I use f1 to make them more clear.
Hope this helps!
Hope this helps!
- Sun Oct 25, 2020 11:41 pm
- Forum: DeBroglie Equation
- Topic: Sapling Week 2 HW_problem #22
- Replies: 7
- Views: 375
Re: Sapling Week 2 HW_problem #22
So for this problem, we are given the wavelength of the matter-wave and asked to calculate the energy it outputs. To find the total kinetic energy of an electron from its wave-like properties, we need to use the Kinetic Energy equation, however, this equation requires the velocity of the particle wh...
- Sun Oct 25, 2020 11:19 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: d orbitals
- Replies: 17
- Views: 659
Re: d orbitals
According to his lecture on the topic, this would mean that the wave function for the electrons in a given atom would have experimentally verifiable solutions that fall into 5 distinct patterns or "lobes". As I understand it, this would be one function that could have 5 general areas of so...
- Sun Oct 25, 2020 11:13 pm
- Forum: *Shrodinger Equation
- Topic: Clarrification of EΨ
- Replies: 5
- Views: 339
Re: Clarrification of EΨ
Are the Hamiltonian functions something that would be unique to each atom, or will all atoms share a set of wave functions?
- Sun Oct 25, 2020 11:10 pm
- Forum: *Shrodinger Equation
- Topic: Additional Audio-Visual Modules
- Replies: 2
- Views: 128
Re: Additional Audio-Visual Modules
I do not believe that there will be any more Audio-Visual Modules, as from Outline 3 onward they are no longer present in the outlines. However, I don't think that this is conclusive it's just my best guess with the information available. Hope this helps!
- Sun Oct 18, 2020 10:55 pm
- Forum: Properties of Light
- Topic: Intensity of light
- Replies: 2
- Views: 142
Re: Intensity of light
I don't know specifically what kind of questions we might be asked on intensity, but it should factor into the wave equations as amplitude. From what I remember from calc, this should be a constant multiplying the rest of the wave equation, but it would be great if someone could give a more mathemat...
- Sun Oct 18, 2020 10:51 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 17469
Re: How are you studying?
I honestly think one of the best ways to study is to teach others. I have a friend in this class, and we take turns explaining how to do difficult problems to each other in theory, then the other person follows the steps laid out and sees if they got the right answer according to the SSM on sapling....
- Sun Oct 18, 2020 10:45 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra
- Replies: 3
- Views: 103
Re: Atomic Spectra
The first line of the question tells us that 1 meter will contain 1,650,763.73 waves of the radiation being emitted. We can flip this on its head to say that 1 wave will have a length of 1 meter / 1,650,763.73 or 6.05780211×10^-7m (605.8 nm). Since visible light ranges from about 400-700nm, we know ...
- Sun Oct 18, 2020 10:24 pm
- Forum: *Black Body Radiation
- Topic: Black Body Radiation
- Replies: 13
- Views: 731
Re: Black Body Radiation
Just as a fun aside, the closest we have come to making a black body material is a set of vertically aligned carbon nanotubes. These allow EM radiation in which then can bounce around in the tubes and get absorbed by the carbon at near-perfect levels. Their unique structure allowed a Japanese team i...
- Sun Oct 18, 2020 10:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Where can I buy a webcam for a reasonable price?
- Replies: 60
- Views: 3523
Re: Where can I buy a webcam for a reasonable price?
My TA told us that using our phone would not be acceptable but that seems to contradict what others are saying in this thread. In any case, I got this webcam https://www.amazon.com/gp/product/B089NWSGDR/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 used off of amazon for dirt cheap (<$10). I'...
- Sun Oct 11, 2020 6:13 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 416211
Re: Rusty on High School Chem [ENDORSED]
I found that the Audio-Visual Focus topics really helped me to shake off the rust I felt after not taking chem for a year. Even though the first couple seem a little basic, they are a great way to get your mind thinking about chemistry and get those neural networks firing! Besides that, everything w...
- Sun Oct 11, 2020 6:06 pm
- Forum: Empirical & Molecular Formulas
- Topic: Stoichiometric Coefficients
- Replies: 3
- Views: 137
Re: Stoichiometric Coefficients
I would just like to add that stoichiometric coefficients do not necessarily represent the number of moles being used in a problem, but the ratios of the number of moles of various compounds in relation to each other. For example, if I was using electrolysis to separate water into hydrogen and oxyge...
- Sun Oct 11, 2020 5:57 pm
- Forum: Significant Figures
- Topic: Sapling #4
- Replies: 10
- Views: 569
Re: Sapling #4
If you think about it, 3000 only has one numerical value and 3 placeholder digits. For example, you would be just as accurate saying 3 x 10^3 or 3000. 3200 on the other hand would necessitate 3.2 x 10^3 to maintain the same level of accuracy. To some extent, this is just a convention of science as w...
- Mon Oct 05, 2020 10:53 am
- Forum: Administrative Questions and Class Announcements
- Topic: Structure of Lectures
- Replies: 9
- Views: 511
Re: Structure of Lectures
Good to know, I watched the new lecture I was just thrown off at first because the music at the beginning was the same. Thanks for all the help guys!
Colm
Colm
- Mon Oct 05, 2020 10:19 am
- Forum: Administrative Questions and Class Announcements
- Topic: Structure of Lectures
- Replies: 9
- Views: 511
Re: Structure of Lectures
I think there is some problem with today's lecture then? The only things that show up in my media resources tab are two bruincasted lectures. Is anybody able to watch live?
Colm
Colm