Search found 108 matches
- Thu Mar 12, 2020 10:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5496
Re: ENDGAME Review Session
Thank you Lyndon!
- Tue Mar 10, 2020 5:37 am
- Forum: Balancing Redox Reactions
- Topic: Balancing redox with h2o
- Replies: 9
- Views: 586
Re: Balancing redox with h2o
I'm quite sure that you use H+ and H2O for acidic reactions but OH- and H2O for basic reactions.
- Tue Mar 10, 2020 5:36 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Week 9 Wednesday lecture
- Replies: 7
- Views: 422
Re: Week 9 Wednesday lecture
Matt Sanruk 2H wrote:Since it is not present in the slowest step we can assume that it is indeed zero order and does not affect the rate
I agree with Matt's rationale, the concentration of a zero-order has no effect on reaction.
- Tue Mar 10, 2020 5:18 am
- Forum: Student Social/Study Group
- Topic: Final
- Replies: 21
- Views: 1370
Re: Final
I think the final will most likely still be taken at the assigned location on Sunday.
- Tue Mar 10, 2020 5:17 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: intermediate species
- Replies: 4
- Views: 352
Re: intermediate species
The specie that's being formed and used during different steps of a reaction and will not show up in the determined rate law.
- Tue Mar 10, 2020 5:16 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Kinetics v Therodynamics
- Replies: 8
- Views: 545
Re: Kinetics v Therodynamics
The two are different aspects of a reaction. The former determines the rate (or how fast) a reaction goes, while the latter considers the spontaneity of the reaction.
- Tue Mar 10, 2020 5:14 am
- Forum: Student Social/Study Group
- Topic: Number of Chemistry Community Posts
- Replies: 45
- Views: 2425
Re: Number of Chemistry Community Posts
In "Your Post", you can track the number of posts and the time of posting as well.
- Fri Mar 06, 2020 1:38 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E° vs E
- Replies: 7
- Views: 488
Re: E° vs E
Enaught is a fixed value for one reaction under standard condition, while E can vary as temperature or concentration of the substances in a reaction changes.
- Fri Mar 06, 2020 1:36 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Electrode masses
- Replies: 8
- Views: 535
Re: Electrode masses
There won't be any effects on the cell potential by merely changing the mass of anode or cathode.
- Fri Mar 06, 2020 1:30 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Concentration Cells
- Replies: 5
- Views: 406
Re: Concentration Cells
Ecellnaught depends on the difference between E cathode and E anode, yet in a concentration cell the two nodes contain the same species, thus making the difference to be 0.
- Fri Mar 06, 2020 1:24 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Grades
- Replies: 22
- Views: 1167
Re: Test 2 Grades
The test will probably be handed back next week during discussion section.
- Fri Mar 06, 2020 1:23 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Favoring reactions
- Replies: 7
- Views: 568
Re: Favoring reactions
In this case, the reverse direction or reactant side is favored since the reaction is spontaneous when Ecellnaught is positive.
- Fri Feb 28, 2020 10:29 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: electrolysis
- Replies: 3
- Views: 259
Re: electrolysis
Electrolysis or electrolytic cell has a negative Ecell potential overall, which makes it nonspontaneous. Examples would include the process of making gold and other metals, such as magnesium.
*According to my TA, the Galvanic cell (spontaneous) is what we should put more emphasis on.
*According to my TA, the Galvanic cell (spontaneous) is what we should put more emphasis on.
- Fri Feb 28, 2020 10:26 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Porous Disk and Salt Bridge
- Replies: 13
- Views: 1174
Re: Porous Disk and Salt Bridge
I agree with the comments above. There's not a difference in efficiency between the two based on what I know of.
- Fri Feb 28, 2020 10:23 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Calculating Standard Potentials
- Replies: 4
- Views: 344
Re: Calculating Standard Potentials
Use the equation ECathode - EAnode; in a Galvanic cell, the standard setup is having anode on the left (oxidation) and cathode on the right (reduction).
- Fri Feb 28, 2020 10:21 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 10
- Views: 698
Re: Test 2
The second page of outline 4 (Thermodynamics) and all of the outline 5 (Electrochem).
- Fri Feb 28, 2020 10:21 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontaneity
- Replies: 12
- Views: 907
Re: Spontaneity
In addition to the sign of Gibbs free energy, the sign of cell potential can also serve as an indicator: if Ecell is greater than zero, the reaction is spontaneous, vice versa.
- Thu Feb 20, 2020 12:06 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding Inert Gas
- Replies: 20
- Views: 1059
Re: Adding Inert Gas
Adding an inert gas (noble gases or gases that's not present in the reaction) increases the pressure of the system, but alters no concentration, thus having no effect on the overall reaction.
- Thu Feb 20, 2020 12:04 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Midterm Q6B
- Replies: 5
- Views: 505
Re: Midterm Q6B
Since DeltaG=DeltaH-T*DeltaS, in order to have a nearly equivalent DeltaG and DeltaH means an insignificant DeltaS (disorder). Thus, A has 3 solids from reactant to 3 solids from the product, indicates DeltaS of the reaction is pretty much zero. Assuming constant temperature for the four reactions, ...
- Wed Feb 19, 2020 11:59 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous
- Replies: 23
- Views: 1169
Re: Spontaneous
DeltaG's sign determines spontaneity. If positive, not spontaneous; if negative, spontaneous; if =0, at equilibrium.
- Wed Feb 19, 2020 11:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Recommended Pathway for Chem Series
- Replies: 13
- Views: 1534
Re: Recommended Pathway for Chem Series
It depends on your preference. Some choose to continue with 14C or taking 14C along with 14BL, but you can also choose to take the lab alone.
- Wed Feb 19, 2020 11:56 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 [ENDORSED]
- Replies: 12
- Views: 683
Re: Test 2 [ENDORSED]
Test 2 is now week 9 during the discussion; it covers materials after midterm excluding kinetics.
- Thu Feb 13, 2020 12:04 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous
- Replies: 23
- Views: 1169
Re: Spontaneous
The sign of Gibb's free energy determines the spontaneity of a reaction.
- Thu Feb 13, 2020 12:01 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy
- Replies: 4
- Views: 298
Re: Entropy
Since entropy is a measure of disorder, higher temperature means more disorder.
- Wed Feb 12, 2020 11:37 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Irreversible Expansion
- Replies: 7
- Views: 434
Re: Irreversible Expansion
Irreversible expansion keeps the pressure constant. It is relatively faster than reversible expansion, yet less efficient because it does less work.
- Wed Feb 12, 2020 11:35 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Significance of open, closed, isolated
- Replies: 22
- Views: 1060
Re: Significance of open, closed, isolated
For a closed system, heat can be exchanged but volume remains constant. An open system has constant pressure yet a changing volume. An isolated system has no energy exchange whatsoever (eg. bomb calorimeter). So, in an isolated system, if it has no exchange of energy, can work be done? What would t...
- Wed Feb 12, 2020 11:27 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Summary of Units
- Replies: 3
- Views: 202
Re: Summary of Units
LBacker_2E wrote:My TA said it is better to use kJ for ∆H, and J for the other values. Do you think this is really important, or is it just a preference?
To me, it seems to be a personal preference. Either would work.
- Wed Feb 05, 2020 10:33 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cp and Cv
- Replies: 10
- Views: 453
Re: Cp and Cv
There's no need to memorize the values. They'll be given if we even encounter related questions.
- Wed Feb 05, 2020 10:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Significance of open, closed, isolated
- Replies: 22
- Views: 1060
Re: Significance of open, closed, isolated
For a closed system, heat can be exchanged but volume remains constant. An open system has constant pressure yet a changing volume. An isolated system has no energy exchange whatsoever (eg. bomb calorimeter).
- Wed Feb 05, 2020 10:29 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Topics on the Midterm
- Replies: 22
- Views: 1058
Re: Topics on the Midterm
Everything for topics 1-4. I believe he said that he will begin and finish covering Gibbs free energy in the lecture this coming Wednesday and Friday. Does anyone know if we will be learning new things next week on Monday and Wednesday? I think Dr. Lavelle will go over past exam questions in class ...
- Wed Feb 05, 2020 10:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 7
- Views: 247
Re: Midterm
Andrew Liang 1I wrote:Are we expected to memorize any equations for the midterm or are they going to give all of them to us on the cover sheet?
I'm sure that all the formulas will be given on the cover sheet.
- Wed Feb 05, 2020 10:26 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: Microstates
- Replies: 7
- Views: 185
Re: Microstates
My understanding is that the value is utilized to calculate entropy in the Boltzmann equation, which denotes as S=kblnW.
- Tue Jan 28, 2020 1:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Thermochemistry Textbook HW
- Replies: 4
- Views: 156
Re: Thermochemistry Textbook HW
Personally I found 4D and 4E doable, but there might be more sections out there.
- Tue Jan 28, 2020 1:18 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: qp vs qv
- Replies: 6
- Views: 337
Re: qp vs qv
I think what you stated is what constitutes the difference between those two q values.
- Tue Jan 28, 2020 1:11 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 11
- Views: 257
Re: Bond Enthalpies
I agree with McKenna. Due to the numbers given in the bond enthalpy chart being averages, this method is not as accurate relatively.
- Tue Jan 28, 2020 1:09 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE BOX
- Replies: 27
- Views: 773
Re: ICE BOX
The cutoff is 10^-3. Yet in cases of weak acids and bases, one may want to check the % ionization to ensure the approximation is valid (i.e, the quadratic formula is still necessary if the final percentage is >5%).
- Tue Jan 28, 2020 1:07 pm
- Forum: Phase Changes & Related Calculations
- Topic: Change in Temperature
- Replies: 10
- Views: 251
Re: Change in Temperature
Correct! Equilibrium constants change as the alteration of the temperature inside the system occurs.
- Thu Jan 23, 2020 5:45 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Kw = (Ka)(Kb)
- Replies: 4
- Views: 176
Re: Kw = (Ka)(Kb)
Correct! 25 degree Celsius is the right temperature to assume.
- Thu Jan 23, 2020 5:44 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa/pKb and Ka/Kb
- Replies: 5
- Views: 159
Re: pKa/pKb and Ka/Kb
The relationship is analogous to that of pH/pOH and [H3O+]/[OH-].
Essentially,
10^-pKa=Ka (same applies for Kb)
pKa=-log(Ka) (same applies for Kb).
Essentially,
10^-pKa=Ka (same applies for Kb)
pKa=-log(Ka) (same applies for Kb).
- Thu Jan 23, 2020 5:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K value
- Replies: 7
- Views: 190
Re: K value
If K is less than 10^-3, you can drop the x in the denominator. I usually do a double-check afterwards by calculating the % ionization; if the % ionization is less than 5, you're good, otherwise, you would have to use the quadratic formula.
- Thu Jan 23, 2020 5:36 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H
- Replies: 10
- Views: 736
Re: Delta H
I agree with Caroline's answer. If positive Delta H, endothermic; if negative Delta H, exothermic.
- Thu Jan 23, 2020 5:34 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa/Pkb vs pH/pOH
- Replies: 3
- Views: 141
Re: pKa/Pkb vs pH/pOH
Though both pKa+pKb and pH+pOH equal to 14, Ka and Kb are constants indicating how well an acid or base dissociates, while [H+] and [OH-] represents the concentration of hydronium and hydroxide ions.
- Thu Jan 16, 2020 10:01 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units in ICE Table
- Replies: 8
- Views: 218
Re: Units in ICE Table
I'm quite sure that all values inputted in ICE Table have to be converted into molarity (mol*L^-1).
- Thu Jan 16, 2020 9:58 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier overview
- Replies: 3
- Views: 99
Re: Le Chatelier overview
All three aforementioned aspects. I recall that K remains unchanged when altering concentration and partial pressure, but when to increase or decrease the temperature, K changes.
- Thu Jan 16, 2020 9:54 am
- Forum: Ideal Gases
- Topic: bars vs atm
- Replies: 8
- Views: 245
Re: bars vs atm
They are both units for measuring pressure. I think as long as your units in one question remain consistent, you're all set.
- Thu Jan 16, 2020 9:53 am
- Forum: Ideal Gases
- Topic: Topics for Test 1
- Replies: 17
- Views: 651
Re: Topics for Test 1
The first two outlines should be the focus. Doing all/most of the homework problems, especially the focus questions, would definitely help a lot. Also, go back to read the textbook for any concepts that seem vague.
- Thu Jan 16, 2020 9:50 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent Ionization
- Replies: 11
- Views: 335
Re: Percent Ionization
That is correct! And I believe that in homework problems the % ionization is under 5% excluding certain outliers.
- Thu Jan 09, 2020 9:59 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Are Both L and Aq Excluded From Equilibrium Constant Expressions?
- Replies: 4
- Views: 249
Re: Are Both L and Aq Excluded From Equilibrium Constant Expressions?
Aqueous solutions should be included in the equilibrium expression. Only solid (s) and liquid (q) are excluded.
- Thu Jan 09, 2020 9:57 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: units of K
- Replies: 10
- Views: 496
Re: units of K
Since it's a constant, not a variable, K does not have a unit. We can also think of this by perceiving the molarity units of products and reactant cancels.
- Thu Jan 09, 2020 9:55 am
- Forum: Ideal Gases
- Topic: Understanding Q
- Replies: 19
- Views: 690
Re: Understanding Q
Correct. We perform the same calculation procedure when solving for Q and K.
- Thu Jan 09, 2020 9:54 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Changing Kc [ENDORSED]
- Replies: 4
- Views: 144
Re: Changing Kc [ENDORSED]
I think the equilibrium constant Kc does not change for the same reaction under the same temperature no matter what masses of reactants one uses.
- Thu Jan 09, 2020 9:52 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solvents
- Replies: 5
- Views: 138
Re: Solvents
Since the change in concentration of the solvent is negligible, we don't include them in the equilibrium expression.
- Tue Dec 03, 2019 12:06 am
- Forum: General Science Questions
- Topic: 50 post grade
- Replies: 25
- Views: 1760
Re: 50 post grade
As long as you did 5 posts weekly and make sure changed our username to your legal name plus your discussion, I think you'll be fine.
- Mon Dec 02, 2019 11:47 pm
- Forum: Biological Examples
- Topic: cisplatin
- Replies: 5
- Views: 386
Re: cisplatin
I agree with the answer above. It's also one of the biological examples Dr. Lavelle expects us to memorize.
- Mon Dec 02, 2019 11:44 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Rydberg equation
- Replies: 9
- Views: 518
Re: Rydberg equation
You're allowed to use both, yet it depends on which one explains the concept better for you.
- Mon Dec 02, 2019 11:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Memorization
- Replies: 15
- Views: 971
Re: Memorization
Yes, we do. I hypothesize the VSEPR questions on the final is going to resemble those from test 2.
- Mon Dec 02, 2019 11:38 pm
- Forum: Naming
- Topic: Cyano vs. Cyanido
- Replies: 2
- Views: 152
Re: Cyano vs. Cyanido
There are two versions of naming, while the former is the older, the latter is the revised name.
- Wed Nov 27, 2019 4:04 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: brackets
- Replies: 13
- Views: 626
Re: brackets
It means that everything inside the bracket is a part of the coordination compound.
- Wed Nov 27, 2019 4:02 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test #2 handback
- Replies: 11
- Views: 702
Re: Test #2 handback
It will be handed back during your discussion session. If your discussion is on Wed, Thurs, of Fri, you will probably get the physical copy back in your discussion session next week.
- Wed Nov 27, 2019 4:00 am
- Forum: Lewis Acids & Bases
- Topic: Identifying Acids and Bases
- Replies: 8
- Views: 442
Re: Identifying Acids and Bases
I agree with Mashkinadze's answer. I personally just memorize the specific strong acids/bases.
- Wed Nov 27, 2019 3:29 am
- Forum: Hybridization
- Topic: sigma or pi?
- Replies: 20
- Views: 1124
Re: sigma or pi?
Just memorize:
single bond: one sigma bond
double bond: one sigma bond, one pi bond
triple bond: one sigma bond, 2 pi bonds
single bond: one sigma bond
double bond: one sigma bond, one pi bond
triple bond: one sigma bond, 2 pi bonds
- Wed Nov 27, 2019 3:27 am
- Forum: Hybridization
- Topic: Hybridization of PF5
- Replies: 4
- Views: 1980
Re: Hybridization of PF5
Since F has 3 lone pairs and one bonded pairs, the electron density is thus tetrahedral, leads to hybridization of sp3.
- Thu Nov 21, 2019 3:02 am
- Forum: Hybridization
- Topic: for test 2
- Replies: 7
- Views: 236
Re: for test 2
Hybridization is not gonna be on Test 2.
- Thu Nov 21, 2019 3:01 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: cisplatin
- Replies: 4
- Views: 177
Re: cisplatin
The positions of the cl- ions are different between cisplatin and transplatin. For cis, the two cl- are on the same side, thus dipole moments doesn't cancel. The two Cl- thus bond with the N of the guanine base pair (forming two bonds).
- Thu Nov 21, 2019 12:27 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 6
- Views: 358
Re: Bond Angles
That is correct. For instance, compounds with AX4 (tetrahedral) formula would have bond angles of 120 degrees, while AX3E (trigonal pyramidal) would have bond angles of slightly less than 120 degrees due to the lone pair.
- Thu Nov 21, 2019 12:22 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle of bent
- Replies: 17
- Views: 1261
Re: Bond Angle of bent
Sorry, I should've clarified: for AX2E2, the bond angle is going to be slightly less than 109.5 degrees, while AX2E is less than 120 degrees. Both VSEPR formula represents bent/angular shape.
- Thu Nov 21, 2019 12:18 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle of bent
- Replies: 17
- Views: 1261
Re: Bond Angle of bent
It's gonna be less than 109.5 degrees because of the lone pair.
- Thu Nov 21, 2019 12:15 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Melting Point
- Replies: 3
- Views: 320
Re: Melting Point
I think melting points share the same trend as boiling points. As atom size gets larger, more polarizable, thus stronger London forces leads to higher melting point.
- Thu Nov 14, 2019 1:43 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: Dipole-Dipole vs. Ion-Dipole
- Replies: 2
- Views: 201
Re: Dipole-Dipole vs. Ion-Dipole
For ion-dipole, you have an ion which carries a charge, thus it has to be considered when evaluating IMF, while dipole-dipole solely depends on dipole moment and size of the molecule.
- Thu Nov 14, 2019 1:38 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Memorization
- Replies: 15
- Views: 971
Re: Memorization
Yup, I'm quite sure that's the majority content on Test 2.
- Thu Nov 14, 2019 1:36 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 3F.5
- Replies: 3
- Views: 247
Re: Problem 3F.5
The dominant force to be considered in 3F 5(c) is the dipole-dipole force, which depends on the size of the molecule; since Iodine is larger than Fluorine, Iodine experience higher diploe moment, which results in a stronger dipole-dipole force.
- Wed Nov 13, 2019 9:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test #2
- Replies: 22
- Views: 2883
Re: Test #2
CandiceNourian1J wrote:Do you think it will also have some information from the midterm as well? Or only new untested topics?
I don't think so, but we should know the basics from the past materials, such as drawing lewis structures.
- Wed Nov 13, 2019 9:35 pm
- Forum: Student Social/Study Group
- Topic: Test 2
- Replies: 7
- Views: 456
Re: Test 2
The test will be in your discussion section next week. The topic covered is everything after the midterm, which includes IMFs and VSPER models/shapes.
- Wed Nov 06, 2019 11:58 pm
- Forum: Resonance Structures
- Topic: resonance hybrid
- Replies: 6
- Views: 353
Re: resonance hybrid
I don't think it's necessary to know to draw a hybrid, but we are expected know the concept.
- Wed Nov 06, 2019 11:54 pm
- Forum: Bond Lengths & Energies
- Topic: Bond lengths
- Replies: 4
- Views: 158
Re: Bond lengths
Bond strength increases from single bonds to triple bonds, and bond length is the opposite, which decreases from single bonds to triples bonds.
- Wed Nov 06, 2019 11:49 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Rydberg equation
- Replies: 9
- Views: 518
Re: Rydberg equation
You can use that equation, but the energy version that's given by Dr. Lavelle explains the concept better for me.
- Tue Nov 05, 2019 2:22 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Midterm review
- Replies: 5
- Views: 363
Re: Midterm review
You're very welcome, I am glad that helped. Good luck studying!
- Tue Nov 05, 2019 2:20 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Midterm review
- Replies: 5
- Views: 363
Re: Midterm review
Personally, I write down the equations and concepts a notecard and I go back to them as I finish reviewing each section.
- Thu Oct 31, 2019 1:43 am
- Forum: Electronegativity
- Topic: Electronegativity trends
- Replies: 5
- Views: 242
Re: Electronegativity trends
It's definitely a trend you need to remember along with the atomic radius, I.E., and electron affinity. Yet it's unnecessary to memorize all the values.
- Thu Oct 31, 2019 1:41 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: What are the octet exceptions?
- Replies: 11
- Views: 488
Re: What are the octet exceptions?
The first four elements, which are H, He, Li, and Be, are the exceptions to the octet rule.
- Thu Oct 31, 2019 1:37 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: D orbital
- Replies: 5
- Views: 206
Re: D orbital
That's correct. The d-orbital can hold 5 pairs of or 10 electrons.
- Thu Oct 31, 2019 1:36 am
- Forum: Ionic & Covalent Bonds
- Topic: Midterm
- Replies: 10
- Views: 485
Re: Midterm
All you need to bring is a pen, a scientific calculator, and your ID. Depending on your last name, the location is gonna be different, check out Dr. Lavelle's website for details.
- Thu Oct 31, 2019 1:32 am
- Forum: Resonance Structures
- Topic: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?
- Replies: 4
- Views: 320
Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?
It's because the resonance hybrid is the actual representation of the structure, which has the same length. While the "alternatives" have different length in double/single bonds, but those are not actual structures.
- Thu Oct 24, 2019 12:02 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: ground state
- Replies: 6
- Views: 503
Re: ground state
There's one difference I noted when Dr. Lavelle talked about the periodic trends. He lectured about electron affinity but didn't mention electronegativity; I searched them up and found out they're different concepts: electron affinity is the energy released when electrons are added to gas-phase atom...
- Wed Oct 23, 2019 10:55 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet Rule
- Replies: 6
- Views: 198
Re: Octet Rule
They don't have enough electrons to complete an octet if I recalled correctly.
- Wed Oct 23, 2019 10:42 pm
- Forum: Resonance Structures
- Topic: defintion
- Replies: 7
- Views: 432
Re: defintion
That's correct. Resonance refers to lewis structure have multiple bonds in different equivalent locations.
- Wed Oct 23, 2019 10:40 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: ground state
- Replies: 6
- Views: 503
Re: ground state
The ground state is the stabilized state, the opposite of excited state. I always use the noble/inert gas to represent the inner electrons and write out the valence electrons. For example, the electron configuration for Chlorine is [Ne]3s2 3p6.
- Wed Oct 23, 2019 10:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: What topic are we on?
- Replies: 11
- Views: 544
Re: What topic are we on?
I'm pretty sure that you will be fine to submit problems from either quantum or chemical bonding section, or both.
- Tue Oct 15, 2019 10:11 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18161
Re: E=hv [ENDORSED]
E=hv is the incoming energy of electromagnetic radiation (photon). The energy needed to remove electron is the work function (represented by a greek alphabet).
- Tue Oct 15, 2019 10:08 pm
- Forum: DeBroglie Equation
- Topic: Calculating Wavelength
- Replies: 5
- Views: 283
Re: Calculating Wavelength
I got the same conclusion/answer as AArmellini did. There is no difference when I used 3 sig.figs in that problem.
- Tue Oct 15, 2019 10:04 pm
- Forum: Properties of Light
- Topic: Variables and what they mean
- Replies: 9
- Views: 463
Re: Variables and what they mean
Lambda represents wavelength and v (squiggly) stands for frequency. It's kind easy to mix up frequency and velocity (velocity's variable is lower-case v).
- Tue Oct 15, 2019 10:01 pm
- Forum: Einstein Equation
- Topic: Einstein Equation [ENDORSED]
- Replies: 5
- Views: 404
Re: Einstein Equation [ENDORSED]
I agree with the answer above that E=hv is the equation used to calculate energy per photon. h is Planck's constant and v is frequency.
- Tue Oct 15, 2019 9:58 pm
- Forum: Photoelectric Effect
- Topic: Speed of Light
- Replies: 29
- Views: 1511
Re: Speed of Light
The speed of light is in fact a constant. I used to use 2.9979*10^8 more often but figured 2.998*10^8 is more commonly applied in this class.
- Thu Oct 10, 2019 2:23 am
- Forum: Limiting Reactant Calculations
- Topic: Net Ionic Equation
- Replies: 6
- Views: 382
Re: Net Ionic Equation
For that' you might want to review the solubility of substances and review the definition of a spectator ion.
- Thu Oct 10, 2019 2:20 am
- Forum: SI Units, Unit Conversions
- Topic: Angstrom
- Replies: 16
- Views: 811
Re: Angstrom
I would recommend familiarizing yourself with all the units to play it safe. An Angstrom is simply a measurement that is equivalent to 10^-10m (or 0.1 nm if you prefer).
- Wed Oct 09, 2019 9:55 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamentals G
- Replies: 4
- Views: 558
Re: Fundamentals G
I personally use the mole to mole conversion: 1 mole of CuSO4.5H2O contains 5 moles of H2O.
- Wed Oct 09, 2019 9:38 pm
- Forum: Empirical & Molecular Formulas
- Topic: How to format formulas
- Replies: 4
- Views: 452
Re: How to format formulas
There's actually something called the hill system that states C atoms and H atoms should be placed first, and others follow in alphabetical order.
- Wed Oct 09, 2019 9:31 pm
- Forum: SI Units, Unit Conversions
- Topic: Test 1
- Replies: 9
- Views: 459
Re: Test 1
The test covers materials from the Review of Chemical & Physical Principles, which are some of the fundamental sections, so I believe the dilution equation is a subject that's likely to be tested.
- Sun Oct 06, 2019 8:27 pm
- Forum: SI Units, Unit Conversions
- Topic: 50 Min test
- Replies: 4
- Views: 140
Re: 50 Min test
It's during your discussion. So if you have discussion on Tuesday, the test is gonna be on the same day. I recommend doing problems from the assigned homework list to prepare.
- Thu Oct 03, 2019 11:55 pm
- Forum: General Science Questions
- Topic: Chem 17 vs. Chem 14A
- Replies: 1
- Views: 117
Re: Chem 17 vs. Chem 14A
It depends on the content your high school teacher covered in honors chem because unlike AP chem, honors chem can be very distinct from school to school. If you are familiar with most of the content in the fundamental section, you are probably in good shape; if not, you might want to spend a decent ...