Search found 102 matches
- Sun Mar 15, 2020 1:22 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: enthalpy constants?
- Replies: 6
- Views: 581
Re: enthalpy constants?
For a detailed description and related exercises, check p.264 in the textbook and 4C exercises.
- Sun Mar 15, 2020 1:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrodes of Concentration Cell
- Replies: 3
- Views: 324
Electrodes of Concentration Cell
Which side of the concentration cell is the negative electrode? Thanks!
- Sun Mar 15, 2020 1:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5688
Re: ENDGAME Review Session
Thank you so much for all your help for the past two quarters :)
- Sun Mar 15, 2020 1:05 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isochoric
- Replies: 10
- Views: 955
Re: isochoric
Based on just definitions, isochoric means constant volume while isometric is having equal dimensions. I hope this helps.
- Sun Mar 15, 2020 12:59 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: catalyst
- Replies: 4
- Views: 365
Re: catalyst
When given a reaction mechanism, the catalyst will be in the reactants side, will be used up, and then produced again by the end, so that in the overall reaction the catalyst isn't used up.
- Sun Mar 08, 2020 8:53 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Intermediate Species
- Replies: 9
- Views: 721
Re: Intermediate Species
The easiest way I can explain this is by an example:
Let's say,
A + B → X
and X → C + D
Then, for the reaction A + B → C + D, X is the intermediate species because although it cancels out and isn't present in the overall reaction, it was still a species in the process.
Let's say,
A + B → X
and X → C + D
Then, for the reaction A + B → C + D, X is the intermediate species because although it cancels out and isn't present in the overall reaction, it was still a species in the process.
- Sun Mar 08, 2020 8:44 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Reaction Mechanism vs Elementary Step
- Replies: 1
- Views: 202
Reaction Mechanism vs Elementary Step
What is the difference between a reaction mechanism and an elementary step?
- Sun Mar 08, 2020 8:41 pm
- Forum: General Rate Laws
- Topic: Arrhenius Equation
- Replies: 3
- Views: 337
Arrhenius Equation
What would be a situation in which to use the arrhenius equation? Is it just to plot ln K vs 1/T?
- Sun Mar 08, 2020 8:28 pm
- Forum: Balancing Redox Reactions
- Topic: e- amount
- Replies: 9
- Views: 661
Re: e- amount
The amount of e- on both sides should be equal for the redox reaction to be fully balanced. You can try multiplying one or both the half reactions to get equal electrons on each side.
- Sun Mar 08, 2020 6:52 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies: 3
- Views: 280
Concentration Cells
Can someone explain how electron transfer in concentration cells occurs?
- Sun Mar 01, 2020 4:36 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L. 1b
- Replies: 1
- Views: 201
Re: 6L. 1b
The n represents the electrons transferred in the redox reaction. So to do that, find the oxidation states of the reactants and products, identify the reduction and oxidation reaction, balance the charges, and the total amount of electrons transferred in this reaction is the n value.
- Sun Mar 01, 2020 4:30 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L Problems: oxidation and reduction
- Replies: 5
- Views: 413
Re: 6L Problems: oxidation and reduction
To figure out which is the oxidation and which is the reduction reaction,The first step is to figure out the oxidation states of each element in the reactants side and products side (there is a video on Khan Academy on common oxidation state patterns). Then, compare each element's oxidation state fr...
- Sun Mar 01, 2020 4:22 pm
- Forum: General Rate Laws
- Topic: Unique Rate
- Replies: 3
- Views: 328
Re: Unique Rate
The unique rate would be -(1/b) × d[P]/dt= (1/a) × d[R]/dt
- Sun Mar 01, 2020 4:19 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: usage of platinum of cell diagrams
- Replies: 5
- Views: 409
Re: usage of platinum of cell diagrams
If there is a solid only on one side, then the other side will contain an inert solid like Platinum. The metal on the other side will not be used for both because you want a metal that won't affect the reaction.
- Sun Mar 01, 2020 1:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 10
- Views: 508
Salt Bridge
What is the role of a salt bridge?
- Sun Feb 23, 2020 8:17 pm
- Forum: Balancing Redox Reactions
- Topic: Steps
- Replies: 7
- Views: 428
Re: Steps
To balance redox reactions, you want to balance the electrons transferred in the reduction reaction and the oxidation reaction. To do so, you want to separate the whole reaction into two half reactions: the reduction reaction (gaining electrons) and the oxidation reaction (losing reaction) by writi...
- Sun Feb 23, 2020 8:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell diagrams
- Replies: 5
- Views: 363
Re: cell diagrams
I don't believe it matters where the cathode and anode are placed as long as you know the direction of electron flow is (from the anode to cathode) or you're writing down the cell diagram setup (like Cu(s)|Cu2+(aq)||Fe3+(aq),Fe2+(aq)|Pt(s)) since the anode is supposed to be on the left side and the ...
- Sun Feb 23, 2020 8:07 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation Numbers/States
- Replies: 8
- Views: 545
Re: Oxidation Numbers/States
Oxidation number and oxidation state are the same thing, to calculate them there are some patterns like the elements in the first column have a +1 charge, the one's in the second column have a +2 charge, the transition metals vary in charge mostly, the halogens have a -1 charge, column 16 usually ab...
- Sun Feb 23, 2020 7:59 pm
- Forum: Balancing Redox Reactions
- Topic: Steps
- Replies: 7
- Views: 428
Re: Steps
To balance redox reactions, you want to balance the electrons transferred in the reduction reaction and the oxidation reaction. To do so, you want to separate the whole reaction into two half reactions: the reduction reaction (gaining electrons) and the oxidation reaction (losing reaction) by writin...
- Sun Feb 23, 2020 7:54 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing the Cell Reaction from the Cell Diagram
- Replies: 1
- Views: 182
Re: Writing the Cell Reaction from the Cell Diagram
Since the Zn reaction is on the left side, it is the anode so it is going through oxidation (losing electrons), so start off by writing down the reaction for the left hand side as Zn(s) to Zn^2+(aq)+2e- On the right side is the Cu reaction which is the cathode so it is undergoing reduction (gaining ...
- Sun Feb 23, 2020 7:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell diagrams
- Replies: 5
- Views: 363
Re: cell diagrams
When given the half reactions, you want to balance the atoms on both sides and multiply the half reactions to have equal electrons transferred on both sides of the reaction. When this is done, the half-reactions can be added together to create the net balanced redox reaction. The cell diagram is mai...
- Sun Feb 16, 2020 9:24 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Work
- Replies: 14
- Views: 1018
Re: Work
When a system does work, work is positive
When work is done on a system, work is negative
When work is done on a system, work is negative
- Sun Feb 16, 2020 9:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Enthalpy and Heat
- Replies: 3
- Views: 311
Enthalpy and Heat
Can someone explain to me the difference between enthalpy and heat? Are they both transfer of heat?
- Sun Feb 16, 2020 9:19 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Laws of thermodynamics
- Replies: 4
- Views: 503
Laws of thermodynamics
What are the three laws of thermodynamics? I was a bit confused when they were mentioned in class.
- Sun Feb 16, 2020 9:16 pm
- Forum: Ideal Gases
- Topic: Equation
- Replies: 4
- Views: 441
Re: Equation
I don't see any equation attached to your post you might want to fix it
- Sun Feb 16, 2020 7:12 pm
- Forum: Balancing Redox Reactions
- Topic: Seperating Redoz RXNS
- Replies: 7
- Views: 398
Re: Seperating Redoz RXNS
By half reactions, Lavelle simply means to separate the oxidation reaction and the reduction reaction to balance one half reaction first, keep track of electrons exchanged and piece it back together with the other half reaction to fully balance the reaction.
- Sun Feb 16, 2020 7:07 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: delta S=qrev/t
- Replies: 4
- Views: 306
delta S=qrev/t
How do you calculate qrev for the equation delta S=qrev/t? Is it usually given or do you need to use other equations based on information given in the question?
- Sun Feb 16, 2020 7:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs free energy
- Replies: 5
- Views: 333
Re: Gibbs free energy
Delta G naught is Gibb's Free Energy with substances in standard state, while delta G isn't. In general, when naught is used, it indicates substance in standard state.
- Sun Feb 16, 2020 6:58 pm
- Forum: Balancing Redox Reactions
- Topic: Memorizing charges
- Replies: 11
- Views: 732
Re: Memorizing charges
For transitional metals, the oxidation states usually vary, so for those I would just go off the compound given. However, it would be a good idea to remember some patterns like columns 1 (+1),2 (+2),16 (-2), and 17 (-1).
- Sun Feb 16, 2020 6:53 pm
- Forum: Balancing Redox Reactions
- Topic: Identifying Elements Undergoing Oxidation/Reduction
- Replies: 5
- Views: 265
Re: Identifying Elements Undergoing Oxidation/Reduction
I forgot to mention the example in my last post. So for the example in your post, to identify the elements, calculate the oxidation state for each of the elements in the reactants and and for each of the elements in the products and if you use the rules from the previous post you can figure out whic...
- Sun Feb 16, 2020 6:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Delta G
- Replies: 6
- Views: 371
Re: Delta G
Delta G naught is Gibb's Free Energy at standard state since the degree mark, naught, indicates substance in standard state
- Sun Feb 16, 2020 6:38 pm
- Forum: Balancing Redox Reactions
- Topic: Identifying Elements Undergoing Oxidation/Reduction
- Replies: 5
- Views: 265
Re: Identifying Elements Undergoing Oxidation/Reduction
A good way to remember how to identify elements undergoing oxidation/reduction is
"LEO the lion goes GER"
LEO: Losing Electrons=Oxidation
GER: Gaining Electrons=Reduction
"LEO the lion goes GER"
LEO: Losing Electrons=Oxidation
GER: Gaining Electrons=Reduction
- Sun Feb 16, 2020 6:35 pm
- Forum: Calculating Work of Expansion
- Topic: Choosing work equation
- Replies: 10
- Views: 813
Choosing work equation
How do you determine which work equation to use based on reversible and irreversible processes?
- Sun Feb 16, 2020 6:27 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibb's Free Energy
- Replies: 7
- Views: 382
Gibb's Free Energy
What exactly is Gibb's Free Energy? What is it calculating?
- Sun Feb 16, 2020 6:22 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: Finding the value of W
- Replies: 3
- Views: 368
Finding the value of W
How do you find the value of W?
- Sun Feb 16, 2020 6:19 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Autoprotolysis
- Replies: 6
- Views: 1181
Autoprotolysis
Is there any other examples of autoprotolysis other than H20?
- Mon Feb 10, 2020 3:33 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=mCdeltaT vs q=nCdeltaT
- Replies: 2
- Views: 111
q=mCdeltaT vs q=nCdeltaT
When should you use each of these equations, q=mCdeltaT vs q=nCdeltaT? Is it simply based on the units given or needed in the answer?
- Mon Feb 10, 2020 3:31 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Spontaneous Reactions
- Replies: 2
- Views: 158
Spontaneous Reactions
How do you know if a reaction is spontaneous? Do you look at entropy or Gibbs free energy? Both?
- Mon Feb 10, 2020 3:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Example 4.c.1
- Replies: 2
- Views: 88
Re: Example 4.c.1
If you look in the textbook page 265 it shows how Cp in monatomic gases is 5/2R and Cv for monatomic gases is 3/2R
- Mon Feb 10, 2020 3:23 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta U= delta H
- Replies: 21
- Views: 1585
Re: delta U= delta H
I think, at constant volume and constant pressure, delta U is equal to delta H.
- Mon Feb 10, 2020 3:16 pm
- Forum: Calculating Work of Expansion
- Topic: w=-nRT(ln V2/V1) Derivation
- Replies: 3
- Views: 194
w=-nRT(ln V2/V1) Derivation
Will we need to derive the equation w=-nRT(ln V2/V1) or any other equations on the midterm?
- Mon Jan 20, 2020 11:57 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Conjugate Acids and Bases
- Replies: 4
- Views: 241
Conjugate Acids and Bases
How do you identify conjugate acids and bases in a chemical reaction? How do they differ from their respective acids and bases?
- Mon Jan 20, 2020 11:52 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Shifts vs Different K values
- Replies: 3
- Views: 195
Shifts vs Different K values
When discussing the shifts in equilibrium from Le Chatelier's Principle, does this simply mean that the concentration will revert to the same K value or will it obtain a different K value?
- Mon Jan 20, 2020 11:27 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kw temperature
- Replies: 8
- Views: 183
Kw temperature
For Kw=1x10^-14, what temperature does this occur?
- Mon Jan 20, 2020 11:20 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5% Rule
- Replies: 6
- Views: 363
5% Rule
Does the 5% rule apply to both chemical equilibrium and acid-base equilibria? Thanks!
- Mon Jan 20, 2020 11:17 am
- Forum: Ideal Gases
- Topic: R constant for PV=nRT
- Replies: 7
- Views: 468
R constant for PV=nRT
What is the the value of R in PV=nRT? I've seen two different values and don't know which is which.
- Mon Jan 20, 2020 11:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kp units
- Replies: 2
- Views: 123
Kp units
When calculating Kp, what unit do you use for the partial pressures?
- Mon Jan 20, 2020 10:59 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solids and Liquids in K
- Replies: 3
- Views: 191
Solids and Liquids in K
Why aren't solids and liquids included in the equation for K?
- Mon Jan 20, 2020 10:56 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Delta G
- Replies: 2
- Views: 89
Delta G
During lecture, Lavelle mentioned the delta G equation, but do we need to know this for the chemical equilibrium unit?
- Mon Jan 20, 2020 10:47 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 2
- Views: 166
Le Chatelier's Principle
Just to make sure, changing the pressure does affect the way the equilibrium will shift only if the change in pressure is from the change in volume?
- Mon Jan 20, 2020 10:41 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H
- Replies: 10
- Views: 775
Delta H
When delta H is positive, is it endothermic or exothermic? And if H is negative?
- Sat Dec 07, 2019 9:15 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Identifying Polydentates
- Replies: 1
- Views: 141
Identifying Polydentates
How do you identify a polydentate and how many times it can attach itself (bidentate, tridentate etc.)?
- Sat Dec 07, 2019 9:11 am
- Forum: Lewis Acids & Bases
- Topic: Strong Acids and Bases
- Replies: 1
- Views: 104
Strong Acids and Bases
Does anyone know what are the common strong acids and bases we should know for the final?
- Sat Dec 07, 2019 9:08 am
- Forum: Identifying Acidic & Basic Salts
- Topic: Identifying Acidic and Basic Salts
- Replies: 3
- Views: 303
Identifying Acidic and Basic Salts
How do you identify acidic and basic salts? Is there certain rules?
- Sat Dec 07, 2019 9:06 am
- Forum: Naming
- Topic: Coordination Compounds and Complexes
- Replies: 3
- Views: 210
Coordination Compounds and Complexes
What is the difference between coordination compounds and complexes?
- Sat Dec 07, 2019 9:04 am
- Forum: Conjugate Acids & Bases
- Topic: studying
- Replies: 7
- Views: 635
Re: studying
I've been doing all the homework problems and the mini final review that Lyndon posted, both are super helpful for studying acids and bases!
- Fri Dec 06, 2019 11:32 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Exam Place
- Replies: 3
- Views: 307
Final Exam Place
Does anyone know where the final will be? Lavelle didn't mention it during lecture.
- Sun Dec 01, 2019 7:11 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis and Bronsted
- Replies: 2
- Views: 154
Re: Lewis and Bronsted
Hey, I just answered someone else's same question with these definitions of Bronsted Acids and Bases and Lewis Acids and Bases. I hope this helps!
Bronsted Acid: proton donor
Bronsted Base: proton acceptor
Lewis Acid: lone pair acceptor
Lewis base: lone pair donor
Bronsted Acid: proton donor
Bronsted Base: proton acceptor
Lewis Acid: lone pair acceptor
Lewis base: lone pair donor
- Sun Dec 01, 2019 7:09 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis v. Bronsted
- Replies: 2
- Views: 124
Re: Lewis v. Bronsted
Here are the definitions of Bronsted Acids and Bases and Lewis Acids and Bases. I hope this helps!
Bronsted Acid: proton donor
Bronsted Base: proton acceptor
Lewis Acid: lone pair acceptor
Lewis base: lone pair donor
Bronsted Acid: proton donor
Bronsted Base: proton acceptor
Lewis Acid: lone pair acceptor
Lewis base: lone pair donor
- Sun Dec 01, 2019 7:01 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Calculating pH of bases
- Replies: 3
- Views: 268
Re: Calculating pH of bases
If you calculate the pOH with the OH- concentration, you can use the equation pH+pOH=14 to solve for pH. I hope this helps!
- Sun Dec 01, 2019 6:58 pm
- Forum: Lewis Acids & Bases
- Topic: Bases
- Replies: 4
- Views: 304
Re: Bases
You can calculate the concentration of OH-, higher the concentration, stronger the base. I hope this helps!
- Sun Dec 01, 2019 6:44 pm
- Forum: Conjugate Acids & Bases
- Topic: Naming Coordinate Compounds
- Replies: 2
- Views: 230
Re: Naming Coordinate Compounds
I would suggest just practicing naming coordinate compounds because there are many coordinate compounds but you start to see the pattern after practicing with a couple of coordinate compounds.
- Mon Nov 18, 2019 9:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs & Polarity
- Replies: 3
- Views: 128
Re: Lone Pairs & Polarity
No, as long as the structure is still symmetrical the structure can have lone pairs.
- Mon Nov 18, 2019 9:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: (CH3)2Be
- Replies: 1
- Views: 98
Re: (CH3)2Be
The Be goes in the middle but there are CH3 on either side of Be so the book is talking about the tetrahedral structure about the carbon atoms instead of the whole structure.
- Mon Nov 18, 2019 9:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: Is ionic or covalent stronger?
- Replies: 31
- Views: 16685
Re: Is ionic or covalent stronger?
I always heard that ionic bonds are stronger, ion-ion bonds are stronger than ion-dipole, dipole-dipole, H bonds, London dispersion forces, and dipole-induced dipole as well.
- Mon Nov 18, 2019 9:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: HS vs HO
- Replies: 4
- Views: 856
Re: HS vs HO
If you mean covalent radius as tightly bound, HO because O is much smaller than S.
- Mon Nov 18, 2019 9:29 pm
- Forum: Dipole Moments
- Topic: Net Dipole Moment
- Replies: 4
- Views: 283
Re: Net Dipole Moment
The net dipole moment is 0 since the dipoles cancel out in an octahedral shape.
- Sun Nov 17, 2019 9:53 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: Dipoles
- Replies: 2
- Views: 135
Dipoles
How do you know if a molecule has a dipole?
- Sun Nov 17, 2019 9:50 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Trend in polarisability and polarizing power?
- Replies: 3
- Views: 322
Re: Trend in polarisability and polarizing power?
Those with high polarizing power are usually smaller cations (top left of periodic table) and those with high polarizability are large anions (bottom right of periodic table). I hope this helps!
- Sat Nov 16, 2019 9:52 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E 11 b)
- Replies: 4
- Views: 214
Re: 2E 11 b)
By adding double bonds, the Cl will gain charges which is not favorable because it's not stable, so instead of adding double bonds, I should have lone pairs. Hope this helps!
- Sat Nov 16, 2019 9:50 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: 169
Re: Size and Electronegativity difference
For H2S vs H2Se, you should look at the size because the electronegativity of S and Se are really similar but size are very different. For SiH4 vs SiF4, you should look at electronegativity because the big difference in electronegativity of H and F. Hope this helps!
- Sat Nov 16, 2019 9:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Model
- Replies: 2
- Views: 196
Re: VSEPR Model
The shape IO2F2- is a seesaw since its AX4E and I included a link to a picture of the lewis structure as well.
https://www.faidherbe.org/site/cours/dupuis/images4/ax5exem2.gif
https://www.faidherbe.org/site/cours/dupuis/images4/ax5exem2.gif
- Sun Nov 10, 2019 5:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Shape of Orbitals
- Replies: 2
- Views: 328
Shape of Orbitals
Do we need to know the shape of the s-, p-, d-, or f- orbitals?
- Sun Nov 10, 2019 5:44 pm
- Forum: *Shrodinger Equation
- Topic: Shrodinger Equation
- Replies: 4
- Views: 461
Shrodinger Equation
What is the purpose of the Shrodinger Equation? What is it solving for?
- Sun Nov 10, 2019 5:40 pm
- Forum: Dipole Moments
- Topic: Dipole Moment
- Replies: 6
- Views: 182
Dipole Moment
What is a dipole moment? Is that the same thing as a molecule having a dipole? Thanks!
- Sun Nov 10, 2019 5:38 pm
- Forum: Electronegativity
- Topic: Electron Affinity and Electronegativity
- Replies: 7
- Views: 441
Electron Affinity and Electronegativity
Can someone explain the difference between electron affinity and electronegativity? Thanks!
- Sat Nov 09, 2019 4:23 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bond Strength
- Replies: 8
- Views: 478
Hydrogen Bond Strength
How strong are hydrogen bonds compared to covalent and ionic bonds?
- Wed Oct 30, 2019 8:48 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Valence-Shell Configuration
- Replies: 1
- Views: 135
Re: Valence-Shell Configuration
The valence shell configuration is writing the electron configurations of the outermost electrons the n represents the number for the shells and for the d-block instead of n its (n-1) which is just the pattern of electron configurations. I hope this helps!
- Wed Oct 30, 2019 8:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Radicals
- Replies: 9
- Views: 627
Radicals
Can someone explain what radicals are and why they're important?
- Tue Oct 29, 2019 7:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 7
- Views: 455
Re: Midterm
If you go on the Chem 14A website there's a test and exam schedule pdf with lots of information and it says the midterm is on Nov.6 from 6-8pm but it doesn't say where the midterm is. I hope this helps!
- Tue Oct 29, 2019 7:46 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.1 Part C
- Replies: 3
- Views: 137
Re: 2A.1 Part C
The valence electrons of manganese is 7 because you add the 2 electrons in the 4s subshell with the 5 electrons in the 3d subshell. Hope this helps!
- Tue Oct 29, 2019 7:37 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: What is the x, y, z?
- Replies: 4
- Views: 1487
Re: What is the x, y, z?
The x and y in 2px and 2py refer to the specific orbitals in the 2p subshell that the electrons that are being discussed are in. The professor does seem to prefer this notation but I'm not sure if it's required. Hope this helps!
- Thu Oct 24, 2019 11:42 am
- Forum: Ionic & Covalent Bonds
- Topic: Cation
- Replies: 23
- Views: 1817
Re: Cation
Cations are atoms that have lost an electron so they have a positive charge. Anions are atoms that have gained an electron so they have a negative charge. Cations and anions are important because some elements are more stable as ions because they can gain their octet by gaining or losing an electron...
- Thu Oct 24, 2019 11:39 am
- Forum: Trends in The Periodic Table
- Topic: Trends
- Replies: 5
- Views: 188
Re: Trends
I think the most important trends to know are electronegativity and ionization energy because it will be important with bonding, but in general you should know the ionic radius and electron affinity trends as well (the trends are pretty similar) just in case there's a question on it. I hope this hel...
- Thu Oct 24, 2019 11:21 am
- Forum: Properties of Electrons
- Topic: Electron transition question
- Replies: 2
- Views: 214
Re: Electron transition question
I got the value +9.73*10^-8 m which is UV light. The problem is that you should have made the energy negative since energy is being emitted (the UV light), so the equation you plug in for energy should be -hc/wavelength. Doing this will give you +9.73*10^-8 m. I hope this helps!
- Tue Oct 22, 2019 10:26 pm
- Forum: Trends in The Periodic Table
- Topic: Ionic Radius
- Replies: 4
- Views: 211
Re: Ionic Radius
The ionic radius trend does show that anions are greater in size than their grounds state atoms and cations are smaller in size than ground state atoms because they lose electrons. However, for the general trend for atomic radius and ionic radius is greatest towards the bottom left because there are...
- Tue Oct 22, 2019 8:41 pm
- Forum: Photoelectric Effect
- Topic: Work Function?
- Replies: 7
- Views: 539
Re: Work Function?
A good question to look at is 1B.15 but the idea is that if a photon hits a metal surface, the work function is the energy required to remove electrons from different metals. This is called the photoelectric effect and the equation is E(photon)- work function = Ek(excess kinetic energy) where E(phot...
- Sat Oct 19, 2019 7:48 pm
- Forum: Properties of Electrons
- Topic: Building Up
- Replies: 2
- Views: 130
Re: Building Up
This is actually due to Hund's rule to be more specific about where the electrons in the p orbital would be. Since there are two electrons in the p orbital in your example, they would not both be in the same orbital because that would increase the energy and the lowest energy possible would be with ...
- Sat Oct 19, 2019 7:45 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: P Orbital specifics
- Replies: 4
- Views: 186
Re: P Orbital specifics
If there is one electron in the p orbital, we would write that the electron is in the 1px orbital but I think it could be any of the px, py, or pz orbitals but its just the order we write it because we aren't yet able to determine the specific orbital the electron is in, px, py, or the pz orbital. I...
- Sat Oct 19, 2019 7:29 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Applications of Hund’s Rule and Pauli Exclusion Principle
- Replies: 2
- Views: 252
Re: Applications of Hund’s Rule and Pauli Exclusion Principle
Hund's Rule says that since electrons repel each other (because they're all negatively charged), electrons in the same sub shell occupy different orbitals with parallel spin to stay at it's lowest energy because the farther away the electrons can be without reaching a high energy is ideal. So when y...
- Sat Oct 19, 2019 7:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Why 3d before 4s
- Replies: 2
- Views: 170
Re: Why 3d before 4s
When we write electron configurations, it is in order of lowest to highest energy and it turns out that 3d is lower energy than 4s, so we put 3d before 4s to keep the pattern of lowest to highest energy going. Hope this helps!
- Sat Oct 19, 2019 7:11 pm
- Forum: Photoelectric Effect
- Topic: Work Funtion
- Replies: 2
- Views: 124
Re: Work Funtion
The work function is how to calculate the threshold energy. The threshold energy is the energy required for an incoming photon to have a greater value of in order to emit energy. Anything less than the threshold energy will not emit any energy. Hope this helps!
- Sun Oct 13, 2019 3:30 pm
- Forum: Properties of Light
- Topic: 1A.5
- Replies: 3
- Views: 155
Re: 1A.5
Gamma rays, X-rays, UV light, Visible light, Microwaves is the order with gamma rays at the highest energy and microwaves with the lowest energy. Hope this helps
- Sun Oct 13, 2019 3:27 pm
- Forum: Properties of Electrons
- Topic: Lyman, Balmer and Paschen Series
- Replies: 2
- Views: 148
Lyman, Balmer and Paschen Series
What are the differences between the Lyman, Balmer and Paschen series? What does the hydrogen atom have to do with these series? Thanks
- Sun Oct 13, 2019 3:13 pm
- Forum: Properties of Electrons
- Topic: Wavelength properties of electrons
- Replies: 4
- Views: 252
Re: Wavelength properties of electrons
I completely agree with the post before and if it helps, you can think of it with the fact that when we measure the motion of a baseball we don't look at wavelength and frequency like we would with an electron, we instead look at mass and velocity because the wavelike properties of a baseball are un...
- Sun Oct 13, 2019 11:18 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 1D.22
- Replies: 1
- Views: 85
Re: 1D.22
If you refer to your 1D.21 post, the explanation is the same. So you would get the answers, a.) 4p, number of orbitals: 3 b.) 5s, number of orbitals: 1 c.) 6d, number of orbitals: 5 d.) 7f, number of orbitals: 7 (Heres is the explanation again) The n-value stays as is and precedes the letter that in...
- Sun Oct 13, 2019 11:13 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 1D.21
- Replies: 1
- Views: 81
Re: 1D.21
a.) 5d, number of orbitals: 5 b.) 1s, number of orbitals: 1 c.) 6f, number of orbitals: 7 d.) 2p, number of orbitals: 3 The n-value stays as is and precedes the letter that indicates the orbital.The l-value corresponds to a s,p,d or f orbital (l=0 is the s orbital, l=1 is the p orbital, l=2 is the d...
- Wed Oct 02, 2019 8:14 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Accuracy and Precision [ENDORSED]
- Replies: 4
- Views: 265
Re: Accuracy and Precision [ENDORSED]
I agree with the post before that it's the ideas that are important and being able to identify in a situation whether it's precise and/or accurate. Also, I believe the idea you vaguely remember is of error bars (which is shown with a plus or minus of the standard error) and standard error itself. Bo...
- Wed Oct 02, 2019 8:02 am
- Forum: Balancing Chemical Reactions
- Topic: How do oxidation numbers help you balance equations?
- Replies: 2
- Views: 203
Re: How do oxidation numbers help you balance equations?
I think your TA was balancing a redox reaction which is a different method of balancing reactions that uses oxidation numbers to balance chemical equations due to the amount of electrons lost and gained in the reaction that need to be accounted for and balanced. If that's the case and you need help ...
- Wed Oct 02, 2019 7:54 am
- Forum: Significant Figures
- Topic: E21b. Sig Figs
- Replies: 5
- Views: 289
Re: E21b. Sig Figs
I can't seem to find the problem, but the amount of sig figs is determined by the sig figs of the amount given (by the given amount with the least sig figs), so although you may get a number with less sig figs when you do your calculations you should refer back to the given amounts. So maybe the boo...