Search found 130 matches
- Sat Mar 14, 2020 9:46 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k
- Replies: 36
- Views: 1628
k
Does the value of k affect the rate of a reaction? Like if k is large, does it mean that the rate of reaction is faster?
- Sat Mar 14, 2020 9:36 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step
- Replies: 2
- Views: 254
Re: Slow step
Are you talking about the pre-equilibrium approach? But yes you can ignore the reverse reaction. If you're talking about the pre-equilibrium approach, then for the fast step before the slow one, the reverse must be taken into account.
- Sat Mar 14, 2020 9:31 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: comparison
- Replies: 4
- Views: 423
Re: comparison
It is easier to use only the concentrations of the reactants rather than both reactants and products. The reaction may go to equilibrium and it is harder to measure the rates of both R and P.
- Fri Mar 13, 2020 2:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 14F
- Replies: 1
- Views: 145
14F
On Lyndon's review worksheet, how would we use the preequilibrium approach to figure out k[A][E]?
- Thu Mar 12, 2020 10:25 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Homework 7E1
- Replies: 4
- Views: 302
Re: Homework 7E1
It also speeds up the rate of the reverse reaction and because a catalyst only affects speed, it does not affect enthalpy.
- Thu Mar 12, 2020 10:23 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: K
- Replies: 3
- Views: 239
K
Why does k have to be in [M]/s?
- Tue Mar 10, 2020 4:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry 14B Final
- Replies: 9
- Views: 743
Chemistry 14B Final
Does anyone know how the Chemistry 14B Final will be given now that classes have gone online? Are all the review sessions cancelled/online now? Will the grading scheme for the course remain the same?
- Sat Mar 07, 2020 9:02 pm
- Forum: General Rate Laws
- Topic: Elementary and overall
- Replies: 2
- Views: 188
Elementary and overall
The exponent in an overall rate is not the same as the exponent in the elementary step right? What is the difference?
- Sat Mar 07, 2020 12:53 am
- Forum: General Rate Laws
- Topic: 7A.15
- Replies: 3
- Views: 348
Re: 7A.15
When you find the ratio between Rate 1 and Rate 4, you will see that [C] will be in zeroth order. That means that now the differential rate law is k[A][B]. Now, when finding the orders of A and B, you don't need to take into account [C] because the reaction does not depend on the concentration of [C].
- Tue Mar 03, 2020 2:35 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6O1
- Replies: 1
- Views: 253
6O1
How come the answer key says to choose the reduction reaction with the highest standard reduction potential and to choose the oxidation reaction with the lowest reduction potential and then proceeds to do the opposite?
- Tue Mar 03, 2020 10:21 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Ions
- Replies: 2
- Views: 189
Ions
When do we add things like NO3 in the half-reaction and when do we not add it? How do we know to add OH- in the reaction?
- Tue Mar 03, 2020 10:15 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L 3 part b)
- Replies: 1
- Views: 169
Re: 6L 3 part b)
These inert electrodes are there because there are no conducting solids for the H2 reaction and the Cl2 reaction. Add them when you don't have a conducting solid. For example, when Fe3+ gets reduced to Fe2+, both still are in aqueous solution. However, you need a conducting solid like Pt(s) that all...
- Tue Mar 03, 2020 10:12 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L7c
- Replies: 2
- Views: 281
6L7c
Why is there a KOH in the answer?
- Tue Mar 03, 2020 10:10 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.5 (d)
- Replies: 1
- Views: 149
Re: 6L.5 (d)
Yeah unfortunately there is no given reaction for Au3+(aq) + 2e-, but there is a reaction for Au3+ +3e- --> Au. So you work with what you have. You still want to end up with some form of the given reaction in the problem. How do you combine the appendix reactions to give you the same Au+(aq) --> Au(...
- Sun Mar 01, 2020 2:06 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Cell Potential
- Replies: 3
- Views: 282
Re: Standard Cell Potential
The objective is to make the cell potential positive so that the cell can do work. If it is negative, the cell is unable to do work and the reaction is unfavorable. Hence, try to combine your values in a way so that you get a positive value. This is for galvanic cells. Electrolytic cells have negati...
- Thu Feb 27, 2020 5:54 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6O1
- Replies: 1
- Views: 177
6O1
Why is water used in this problem? They said that SO4- doesn't oxidize and I am wondering why?
- Thu Feb 27, 2020 10:23 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Hg and Hg2
- Replies: 1
- Views: 190
Hg and Hg2
Can I assume that 2Hg has no charge while Hg2 has a 2+ charge?
- Tue Feb 25, 2020 11:13 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Cell Diagram to Redox Reactions
- Replies: 2
- Views: 202
Re: Cell Diagram to Redox Reactions
How do we know that 2Cl- is being oxidized to Cl2 rather than Cl2 being reduced to 2Cl-?
- Tue Feb 25, 2020 10:38 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Cell Diagram to Redox Reactions
- Replies: 2
- Views: 202
Cell Diagram to Redox Reactions
Is there a guideline for translating cell diagrams to redox reactions? For example, in 6N3c, the book switches the anode and the cathode so that the anode reaction is on the right and the cathode reaction is on the left.
- Tue Feb 25, 2020 10:27 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N3c
- Replies: 2
- Views: 245
6N3c
In the 6N3 c) problem, the book combines pressure and concentration in the Q expression. I know that they cancel out the units of pressure, but I still don't understand?
- Tue Feb 25, 2020 6:12 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.1
- Replies: 2
- Views: 256
Re: 6N.1
I think you're looking at the wrong problem for the answer.
- Tue Feb 25, 2020 6:10 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: log and ln in Nernst
- Replies: 8
- Views: 533
log and ln in Nernst
When do we use log and when do we use ln when using the Nernst equation? Or does it not matter?
- Sat Feb 22, 2020 10:22 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Hg
- Replies: 2
- Views: 220
Hg
What is the difference between 2Hg^2+ and Hg2^2+? Does one reduce to the other?
- Fri Feb 21, 2020 8:59 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: H2O, O2 in 6L7b
- Replies: 1
- Views: 183
H2O, O2 in 6L7b
There are two reactions involving oxygen in basic and acidic solution. How do I determine which one is the anode and which one is the cathode?
- Fri Feb 21, 2020 4:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: galvanic cell
- Replies: 2
- Views: 165
Re: galvanic cell
I think a nonspontaneous reaction requires an external input of energy, like charging a battery. And if it's dead then yes I don't think any reaction happens unless you add that external energy.
- Fri Feb 21, 2020 4:36 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 3
- Views: 226
Re: Salt Bridge
Sorry, I forgot the positive ion. If it's a salt bridge, something like NaCl will be inside. So if Cl- moves to the side that is being oxidized, Na+ would move to the side that is being reduced.
- Fri Feb 21, 2020 4:30 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 3
- Views: 226
Re: Salt Bridge
It allows ions to flow between the solutions so as to keep both of the solutions in the cells neutral. For example, if Zn is being oxidized to Zn2+, ions like Cl- will flow through the salt bridge to keep the Zn side from becoming too positive.
- Fri Feb 21, 2020 4:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing half reactions given cell diagram
- Replies: 1
- Views: 138
Writing half reactions given cell diagram
If Hg is being oxidized in Hg2Cl2, do we write Hg --> 1/2Hg2 or 2Hg -- Hg2? Do I include the Cl2?
- Fri Feb 21, 2020 4:21 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 2
- Views: 179
Cell Diagram
If the cell diagram has all single lines, how can we determine where the porous disk so as to determine reductions and oxidations?
- Fri Feb 14, 2020 9:51 pm
- Forum: Calculating Work of Expansion
- Topic: work = 0
- Replies: 14
- Views: 1346
Re: work = 0
I think it is because the system isn't pushing/expanding any pressure from the outside
- Fri Feb 14, 2020 9:46 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Delta S
- Replies: 2
- Views: 177
Re: Delta S
To add to the previous post, in an irreversible reaction, delta S is 0 because the surroundings is basically a vacuum. So yes, there is no opposing force
- Fri Feb 14, 2020 9:45 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: 4F.1
- Replies: 2
- Views: 201
Re: 4F.1
Yes, because the temperature is larger in the denominator, the fraction would be smaller compared to if the temperature was smaller. This is also why a certain amount of heat has more effect on the entropy when the temperature is lower.
- Fri Feb 14, 2020 9:42 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: Residual Entropy
- Replies: 7
- Views: 579
Re: Residual Entropy
It is the only entropy that is left after you take out all types of entropy like thermal entropy. When you reduce the temperature and try to get to 0 Kelvin, the molecules would not be in motion. The only entropy that would be left is the positional entropy. One molecule could be in multiple orienta...
- Fri Feb 14, 2020 9:17 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy in reversible and irreversible
- Replies: 3
- Views: 287
Entropy in reversible and irreversible
What is the difference in entropy when it comes to a reversible reaction? Irreversible? Do we calculate it the same way using the deltaS=nRln(V2/V1)?
- Wed Feb 12, 2020 12:20 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Why is delta U a state function?
- Replies: 4
- Views: 372
Re: Why is delta U a state function?
Two systems can transfer different amounts of heat and do different amounts of work and still arrive at the same deltaU.
- Sun Feb 09, 2020 6:53 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4F11
- Replies: 1
- Views: 75
4F11
This problem requires the two S equations. The answer key uses R for change in volume AND change in temperature. When do we use C and when do we use R?
- Sat Feb 08, 2020 10:32 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.5
- Replies: 2
- Views: 479
Re: 4J.5
The Δ G value in the table will be a bit off compared to if you were to actually calculate it using the values of ΔH and ΔS in Δ G = Δ H − T Δ S
- Thu Feb 06, 2020 9:03 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: chen discussion [ENDORSED]
- Replies: 5
- Views: 213
Re: chen discussion [ENDORSED]
When do we use C and when do we use R?
- Thu Feb 06, 2020 9:02 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Homework Problem 4F.9
- Replies: 3
- Views: 130
Re: Homework Problem 4F.9
You use the same format as volume, but this time you put P1 above P2 because of Boyle's Law. P1V1=P2V2, so P1/P2=V2/V1. This makes sense because pressure decreases when volume increases. You could expect the entropy to increase.
- Wed Feb 05, 2020 10:16 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4F12
- Replies: 3
- Views: 136
Re: 4F12
Wait, sorry the book uses R in 4F11, but 4F12 tests the same concept
- Wed Feb 05, 2020 10:15 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4F12
- Replies: 3
- Views: 136
4F12
When do we use nCvln(T2/T1) and when do we use nRln(T2/T1)? In this problem the book uses R instead of C and I was wondering when we should use either of them?
- Mon Feb 03, 2020 10:39 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4D15
- Replies: 1
- Views: 83
4D15
How come the answer for this problem is -312 kJ/mol instead of 312 kJ/mol? I used the third method to find the answer, and I got 312. How did the book get a negative answer?
- Mon Feb 03, 2020 12:58 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: States of a system
- Replies: 3
- Views: 79
Re: States of a system
It is the number of states to the power of the number of particles.
- Fri Jan 31, 2020 9:32 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4A5
- Replies: 2
- Views: 123
4A5
The answer key uses the reversible isothermic equation to answer part b, but we didn't learn that in lecture? Are we supposed to know it for the midterm?
- Thu Jan 30, 2020 9:48 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: qp and qv
- Replies: 8
- Views: 383
qp and qv
Why is qp=∆H and not qv?
- Thu Jan 30, 2020 9:40 am
- Forum: Calculating Work of Expansion
- Topic: Integral
- Replies: 4
- Views: 213
Integral
Will we be using the integral equation? When will we use w=-P∆V and when will we use the integral? What is the difference between them? Is it because in the integral, external pressure may not be constant?
- Thu Jan 30, 2020 9:33 am
- Forum: Calculating Work of Expansion
- Topic: reversible and irreversible
- Replies: 2
- Views: 66
reversible and irreversible
What is the clear difference between reversible and irreversible expansion? I am confused about the role external pressure plays on both of these.
- Mon Jan 27, 2020 8:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: #4C11
- Replies: 2
- Views: 135
#4C11
The answer key gives 6.01 kJ/mol as one of the values. Where did they get it?
- Mon Jan 27, 2020 7:43 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q and deltaH
- Replies: 3
- Views: 96
q and deltaH
What is the difference between q and delta H?
- Wed Jan 22, 2020 8:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Acids and Bases
- Replies: 6
- Views: 172
Re: Acids and Bases
No we don't. Dr. Lavelle said that polyprotic acids required multiple steps for each time the acid donates a proton.
- Wed Jan 22, 2020 8:23 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 6D 15b
- Replies: 2
- Views: 160
Re: 6D 15b
Ka should be in a table in the book. This problem tests 14A material. You're supposed to know that Al3+ can serve as a metal cation that can have multiple bonds (coordination compounds)
- Wed Jan 22, 2020 8:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximation
- Replies: 2
- Views: 81
Re: Approximation
You can check the percent protonation to see if it's less than 5%. You can also check the Ka/Kb value. if the value is less than 10^-3, you can almost safely approximate.
- Wed Jan 22, 2020 8:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box vs just solving
- Replies: 2
- Views: 89
Re: ICE Box vs just solving
Use the ICE box for when the problem asks for something like the pH or pOH of a weak acid/base and you have to find the concentration of the H3O+/OH-. Or, when the problem asks for the equilibrium compositions of the reaction. Then you'd have to find the concentrations for the reactants using the IC...
- Wed Jan 22, 2020 8:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G5
- Replies: 1
- Views: 87
5G5
Can someone explain the difference between the third and fourth flask in this problem?
- Tue Jan 21, 2020 9:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Autoprotolysis
- Replies: 1
- Views: 122
Re: Autoprotolysis
If [H3O+] < 10^-7, then the solution is considered neutral because we know that autoprotolysis generates 10^-7 M H3O+
- Thu Jan 16, 2020 5:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Negative pH
- Replies: 6
- Views: 260
Re: Negative pH
You get a negative pH when the concentration provided is greater than 1
- Thu Jan 16, 2020 5:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: weak acids and weak bases
- Replies: 3
- Views: 166
Re: weak acids and weak bases
I'm not exactly sure what kind of calculations you are talking about You would have to use an ICE chart, with Ka and Kb. The problem would most likely ask for the pH/pOH and the concentrations of H3O+/OH-.
- Tue Jan 14, 2020 6:01 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic and exothermic reactions
- Replies: 11
- Views: 1108
Endothermic and exothermic reactions
Can someone explain why endothermic reactions favor product formation while exothermic reactions favor reactant formation? I don't understand how the graphs and delta H relate to the concept when explaining product/reactant formation.
- Tue Jan 14, 2020 4:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I.16
- Replies: 2
- Views: 109
Re: 5I.16
Yeah, I was wondering if K would just equal to the total pressure (7.68) bar? Since solids and liquids are not included in the constant expression?
- Tue Jan 14, 2020 4:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5l.13
- Replies: 2
- Views: 145
Re: 5l.13
Create an ICE chart for the reaction Cl2-->2Cl (it's in the table 5G2). You will find the equilibrium compositions of Cl2 and Cl using the given Kc at 1000 K. Do the same thing for F2. Compare the concentrations you find between Cl2 and Cl/F2 and F. If the concentration of the reactant is greater th...
- Tue Jan 14, 2020 4:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6B.9 Hw problem
- Replies: 3
- Views: 166
Re: 6B.9 Hw problem
I think we get that when the pH scale exceeds 14. This usually occurs when the molarity or concentration of H3O+ or OH- is greater than 1.
- Fri Jan 10, 2020 10:07 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Today's Lecture
- Replies: 3
- Views: 150
Re: Today's Lecture
The proper explanation was the comparison of Q to K, where the concentration doubled due to the volume being halved. When the concentration doubled and we found Q(this is before we wait for the system to return to equilibrium), we found that Q<K. And when Q<K, the reaction shifts to the right.
- Fri Jan 10, 2020 9:50 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: predicting effects
- Replies: 9
- Views: 446
Re: predicting effects
I think because it's on the products side, removing one of the products would increase the production of both compounds (NO and SO3)?
- Thu Jan 09, 2020 12:57 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q vs K
- Replies: 8
- Views: 233
Re: Q vs K
Q is for when the reaction isn't at equilibrium. K is for when the reaction is at equilibrium.
- Thu Jan 09, 2020 12:55 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K expression
- Replies: 6
- Views: 216
Re: K expression
There technically isn't a concentration for a solid b/c it doesn't make sense. We're measuring the change in concentration of compounds in K. As for pure liquids, the concentration isn't changed much. The change is negligible it's practically 0. So if we put something like the concentration of water...
- Thu Jan 09, 2020 12:51 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G3
- Replies: 8
- Views: 348
5G3
Do we include H2O in the gas phase? I know we don't include it in the liquid phase but I am unsure about gas.
- Thu Jan 09, 2020 12:50 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K being small or large
- Replies: 4
- Views: 136
Re: K being small or large
Like the post above me said, the reaction favors the reactants if K is small. The reactants are more stable. If K is big, the reaction favors the products and the products are more stable.
- Sat Dec 07, 2019 2:09 pm
- Forum: Dipole Moments
- Topic: Dipole Moments Cancel in Tetrahedral?
- Replies: 5
- Views: 1053
Re: Dipole Moments Cancel in Tetrahedral?
If you draw the tetrahedral lewis structure in its actual shape, you would see that they would not cancel due to the vectors pointing upwards or downwards. The structure does not have bond angles of 90º. There would be a net dipole going up or down. For example, CH2Cl2 would still be polar and like ...
- Tue Dec 03, 2019 8:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles of compounds with different atoms
- Replies: 2
- Views: 506
Re: Bond angles of compounds with different atoms
I'm not sure if it has what I'm asking. I'm asking if having different atoms surrounding the central atom affects the bond angles?
- Tue Dec 03, 2019 12:15 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles of compounds with different atoms
- Replies: 2
- Views: 506
Bond angles of compounds with different atoms
What would the bond angle of COH3 be? I know that it is a tetrahedral structure, but would the bond angle be any different due to the oxygen atom?
- Mon Dec 02, 2019 10:56 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Oxides of main group elements
- Replies: 2
- Views: 205
Oxides of main group elements
Are oxides of main group elements considered bases? Or do they have to react with water to form bases/acids? For example, Na2O has to react with H2O to form NaOH. Is Na2O considered a base? Or is it the NaOH?
- Mon Dec 02, 2019 10:11 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: HW 6D11
- Replies: 2
- Views: 321
Re: HW 6D11
Sorry I forgot to mention that you should look for the strong conjugate acids/bases that come from weak acids/bases. Like for example in a) NH4Br, Br- is a weak conjugate base of the strong acid HBr so it doesn't affect the pH and you shouldn't pay attention to that. NH4+ on the other hand, is a str...
- Mon Dec 02, 2019 10:05 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: HW 6D11
- Replies: 2
- Views: 321
Re: HW 6D11
In c), F- is the anion of a weak acid (HF). In lecture today we learned that the conjugate base of a weak acid will raise the pH of the solution by removing protons from water to generate OH-. As a result, the pH will be >7. e) Al3+ is the transition metal that is hydrated and has strong e- withdraw...
- Fri Nov 29, 2019 2:34 pm
- Forum: Hybridization
- Topic: #2F16
- Replies: 1
- Views: 157
#2F16
In problem 2F16, it asks if the N2px orbital participates in hybridization for NH2+ and NH2- if the 2px orbital is lying perpendicular to the plane of the molecule. I am not quite sure as to how to answer this question. How do I know if a particular orbital participates in a hybridization?
- Wed Nov 27, 2019 4:08 pm
- Forum: Biological Examples
- Topic: EDTA
- Replies: 8
- Views: 572
Re: EDTA
It is ethylene-diamine-tetra-acetate and it removes metals from the blood by chelating or binding to cations, aka metals. It has six binding sites(2 amino-nitrogen atoms and 4 carboxylic groups)
- Wed Nov 27, 2019 4:04 pm
- Forum: Naming
- Topic: OH2 vs H2O Coordination Complex Chemical Formula
- Replies: 3
- Views: 171
Re: OH2 vs H2O Coordination Complex Chemical Formula
There really is no difference between the two as both are water, but it is most likely to show that it is oxygen that binds to the complex and not the hydrogen. The formula OH2 gives a more accurate depiction of the structure just like how Dr. Lavelle reversed NH3 and H3N during lecture.
Re: 9C.3
The order in which you put your ligands does not matter, but the naming process matters because then you have to take into account alphabetical order.
Re: HW 9c.9
6 because en has two binding sites. Because it is a bidentate and there are two of them, it binds at four sites. Add the four to the two Cl sites and you get 6.
- Wed Nov 27, 2019 3:16 pm
- Forum: Lewis Acids & Bases
- Topic: Bronsted and Lewis Acids
- Replies: 4
- Views: 262
Bronsted and Lewis Acids
What is the difference between Bronsted and Lewis acids and bases?
#9C3 d
How come bisoxalato comes before diaqua in the name? For reference, the name of the complex is sodium bisoxalato(diaqua)ferrate(III). I thought we were supposed to ignore the greek prefixes and only pay attention to the ligand itself?
- Thu Nov 21, 2019 10:28 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Problem 3F10 b
- Replies: 6
- Views: 451
Problem 3F10 b
Which structure has stronger IMFs? SiF4 or Si2F2?
- Wed Nov 20, 2019 6:56 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: 3F.19
- Replies: 5
- Views: 472
Re: 3F.19
doesn't the strength of london disperson forces take priority over dipole-dipole forces when determining which compound has a higher boiling point? Not really. You have to first compare IMF strength before comparing different London dispersion force factors like size or number of electrons. In this...
- Tue Nov 19, 2019 3:54 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: H-bonding vs ion-dipole
- Replies: 4
- Views: 170
H-bonding vs ion-dipole
Which interaction is stronger than the other? Hydrogen bonds or ion-dipole interactions?
- Tue Nov 19, 2019 12:05 am
- Forum: Dipole Moments
- Topic: 2E30
- Replies: 1
- Views: 189
2E30
Question 2E30b asks which molecule has the largest dipole moment and I am conflicted between 1 and 3. Can someone help? Thanks!
- Mon Nov 18, 2019 10:34 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: ion dipole interactions
- Replies: 3
- Views: 295
Re: ion dipole interactions
Yes. The phrase "like dissolves like" basically means that polar molecules dissolve in polar molecules, or anything with a charge basically. Because Cl- ion has a negative charge, it will be hydrated. But something like C6H6 cannot dissolve in water or polar substances because it is a nonp...
- Mon Nov 18, 2019 10:32 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 bonds
- Replies: 4
- Views: 293
Re: hydrogen bonds
Yes they are considered a special dipole-dipole interaction. For example, (HF interacting with NH). However, it is considered stronger than other dipole-dipole interactions.
- Sat Nov 16, 2019 8:17 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: Size and Electronegativity difference
- Replies: 3
- Views: 171
Size and Electronegativity difference
When do we look at size and when do we look at electronegativity difference when it comes to checking to see which molecule has the higher boiling point? For example, H2S vs H2Se or SiH4 vs SiF4. Do I look at the electronegativity or the size/polarizability of the molecule?
- Sat Nov 16, 2019 7:56 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: Potential energy
- Replies: 1
- Views: 91
Potential energy
Can someone explain to me what exactly potential energy is between interacting molecules?
- Thu Nov 14, 2019 12:01 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: Polar Vs Nonpolar
- Replies: 7
- Views: 429
Re: Polar Vs Nonpolar
to rephrase: How can I tell when a molecule has a dipole moment?
- Thu Nov 14, 2019 11:53 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Polar Vs Nonpolar
- Replies: 7
- Views: 429
Polar Vs Nonpolar
How can we tell if a molecule is polar or nonpolar? For example: CH2Cl2. How would I be able to find the forces that occur between that molecule besides London forces?
- Thu Nov 14, 2019 11:43 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Ion-Dipole
- Replies: 2
- Views: 121
Re: Ion-Dipole
I get what the post above is saying, but what does "extent of hydration" mean? Is it like how many H2O molecules the ion attracts?
- Thu Nov 14, 2019 11:40 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: question concerning london dispersion forces and molecular formula
- Replies: 2
- Views: 84
Re: question concerning london dispersion forces and molecular formula
The "increase in mass" actually refers to the increase in C and H atoms because an increase in mass means an increase in the number of electrons. So actually it does not have much to do with the actual mass but rather the increase in the number of electrons when you add C and H. This cause...
- Thu Nov 14, 2019 11:01 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Electronegativity and Diplole Moments
- Replies: 2
- Views: 119
Re: Electronegativity and Diplole Moments
In addition to the post above me, this gives rise to intermolecular interactions. The partial charges on the molecules can induce dipoles on other molecules.
- Thu Nov 14, 2019 10:59 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: London vs Dipole induced dipole
- Replies: 2
- Views: 174
London vs Dipole induced dipole
I know in lecture that Dr. Lavelle said that London interactions and dipole-induced dipoles were similar and interchanged, but the book says that London forces are between nonpolar molecules while dipole-induced dipoles were between a polar molecule and a nonpolar molecule. Which is it?
- Fri Nov 08, 2019 9:55 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Water molecules
- Replies: 9
- Views: 975
Re: Water molecules
It uses both of its hydrogens to form hydrogen bonds with other water molecules but keep in mind that these are not actual bonds. They are interactions between the oxygen atom and the hydrogen atom.
- Fri Nov 08, 2019 9:51 am
- Forum: Photoelectric Effect
- Topic: Midterm 1
- Replies: 9
- Views: 699
Re: Midterm 1
Emily_4B wrote:Do you guys know if we’ll get the midterm back or be able to look at it in office hours to review this question?
I was told that we would get our midterm back next Wednesday during lecture.
- Fri Nov 08, 2019 9:46 am
- Forum: Hybridization
- Topic: Pi bonds
- Replies: 8
- Views: 994
Re: Pi bonds
605110118 wrote:What is the difference between pi and sigma?
sigma is all single bonds and pi is the second bond in a double bond
- Fri Nov 08, 2019 9:44 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Formal Charge
- Replies: 9
- Views: 1449
Re: Formal Charge
VioletKo3F wrote:What's the equation for the formal charge?
V-(L+S/2) where V is for valence electrons, L is for number of lone electrons, and S is for number of shared electrons.
- Fri Nov 08, 2019 9:41 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability vs Polarizing Power
- Replies: 15
- Views: 1165
Re: Polarisability vs Polarizing Power
To add to the replies above, a large anion is usually polarizable because the outer electrons are further from the nucleus and are more likely to feel less of an effective nuclear charge. Meanwhile, a small cation has more polarizing power because of its stronger nuclear charge.
- Fri Nov 08, 2019 9:36 am
- Forum: Sigma & Pi Bonds
- Topic: Double bond
- Replies: 15
- Views: 590
Re: Double bond
How would a double bond help stabilize a structure? In most cases, it would help reduce the formal charge of the atom to 0. For example, oxygen with a single bond and 3 lone pairs has a formal charge of -1. But if you change its bond to a double bond with two lone pairs, it will have a formal charg...