Search found 106 matches

by SLai_1I
Sat Mar 06, 2021 3:02 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: kinetics vs. thermodynamics
Replies: 23
Views: 212

Re: kinetics vs. thermodynamics

Kinetics focuses on the speed or rate of the reaction while thermodynamics focuses on the initial and final state. This is why most thermo functions are state functions.
by SLai_1I
Sat Mar 06, 2021 3:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Time
Replies: 45
Views: 155

Re: Final Exam Time

The final is on 3/14 from 9:30AM - 11:00AM. As most people are saying the review is on Saturday.
by SLai_1I
Sat Mar 06, 2021 2:41 pm
Forum: First Order Reactions
Topic: Graphing
Replies: 12
Views: 46

Re: Graphing

I'd say we should be familiar with how the graphs look for first, second, and zero order reactions.
by SLai_1I
Fri Mar 05, 2021 10:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Studying for Final
Replies: 17
Views: 47

Re: Studying for Final

I'm probably going to go through all the textbook problems again because they sometimes reappear on the exams. I also plan on going to the UA review workshops.
by SLai_1I
Fri Mar 05, 2021 10:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Adding Pt(s)
Replies: 12
Views: 39

Re: Adding Pt(s)

We use Pt(s) when one side of the cell diagram doesn't have a solid conductor. When you see this, you add Pt(s) to that side.
by SLai_1I
Sun Feb 28, 2021 3:50 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode/Cathode
Replies: 45
Views: 82

Re: Anode/Cathode

The anode is on the left while the cathode is on the right.
by SLai_1I
Sun Feb 28, 2021 3:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Moles in ΔG = -nFE
Replies: 45
Views: 98

Re: Moles in ΔG = -nFE

To find the value of n, we have to first balance the redox equation we are working with. Doing so should reveal the moles of electrons that are canceled out.
by SLai_1I
Sun Feb 28, 2021 3:44 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: coulomb?
Replies: 18
Views: 50

Re: coulomb?

A coulomb is a just a unit to measure electrical charge. It should be noted that 1 Volt = 1 Joule / 1 Coulomb. This would mean that 1 Coulomb = 1 Joule / 1 Volt.
by SLai_1I
Sat Feb 27, 2021 10:50 pm
Forum: Administrative Questions and Class Announcements
Topic: struggling
Replies: 73
Views: 274

Re: struggling

I'd recommend going to step up sessions and workshops. I've found those to be really helpful in preparing for exams. Good luck on the final!
by SLai_1I
Sat Feb 27, 2021 10:39 pm
Forum: Balancing Redox Reactions
Topic: Oxidation vs Reduction
Replies: 30
Views: 68

Re: Oxidation vs Reduction

Lavelle went over the LEO acronym in class, but another one I've heard is popular is OIL RIG:

O: Oxidation
I: Is
L: Losing electrons

R: Reduction
I: Is
G: Gaining electrons

Hope this helps!
by SLai_1I
Sat Feb 27, 2021 10:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridges
Replies: 37
Views: 71

Re: Salt Bridges

The salt bridge is implemented so that positive and negative charges don't build up too heavily on either side. The bridge provides charges ions to balance out the anode and cathode sides.
by SLai_1I
Sat Feb 27, 2021 10:32 pm
Forum: Balancing Redox Reactions
Topic: PSA on Sapling #5 for week 7/8
Replies: 3
Views: 37

Re: PSA on Sapling #5 for week 7/8

Thanks for the heads up, I was stuck on one to until I switched around the components of the equation. Thank you!
by SLai_1I
Sat Feb 27, 2021 10:30 pm
Forum: Student Social/Study Group
Topic: Chem 14B Final
Replies: 86
Views: 224

Re: Chem 14B Final

I'd say the final questions are similar to that of the midterms.As for studying, I'd recommend redoing all the textbook problems and going to step up sessions if you have time. Good luck !
by SLai_1I
Mon Feb 22, 2021 3:00 pm
Forum: Student Social/Study Group
Topic: Chem 14B Final
Replies: 86
Views: 224

Re: Chem 14B Final

I know this is a little late, but I find that the textbook problems Dr. Lavelle assigns are usually similar to what the test will be like. Sometimes, the problems from the book appear on the exam. I also think workshops held by UA's are helpful if you have the time to attend them.
by SLai_1I
Mon Feb 22, 2021 2:57 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Units for delta G
Replies: 31
Views: 366

Re: Units for delta G

The unit for delta G is just kJ.
by SLai_1I
Mon Feb 22, 2021 2:57 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy value
Replies: 17
Views: 40

Re: Entropy value

Entropy measures the disorder in a system. A positive change in entropy is usually associated with a spontaneous process, while a negative change in entropy is usually associated with a non-spontaneous one.
by SLai_1I
Thu Feb 18, 2021 6:58 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U in Isothermal Systems
Replies: 4
Views: 22

Delta U in Isothermal Systems

Is delta U always equal to zero in isothermal systems (reversible or irreversible)?
by SLai_1I
Thu Feb 18, 2021 10:30 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Delta S for Isothermal
Replies: 8
Views: 30

Delta S for Isothermal

Can the Delta S = nRln(V2/V1) be used for only isothermal reversible, or can it be used for isothermal irreversible as well?
by SLai_1I
Sat Feb 13, 2021 3:14 pm
Forum: Calculating Work of Expansion
Topic: Sign of work
Replies: 25
Views: 53

Re: Sign of work

Work done on the system is positive, while work done by the system is negative.
by SLai_1I
Sat Feb 13, 2021 3:13 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Difference between ΔS° and ΔS
Replies: 9
Views: 52

Re: Difference between ΔS° and ΔS

The delta S with the naught (the degree-like symbol) gives the change in entropy at equilibrium.
by SLai_1I
Sat Feb 13, 2021 3:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Can We Review our Exams?
Replies: 69
Views: 254

Re: Can We Review our Exams?

If you want to review your past exams, I think you need to schedule an appointment with your TA to do it.
by SLai_1I
Sat Feb 13, 2021 3:10 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: ΔH and q
Replies: 6
Views: 51

Re: ΔH and q

I believe in lecture Lavelle stated that q=delta H at constant pressure, and q=delta U at constant volume.
by SLai_1I
Sat Feb 13, 2021 3:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: kPa to atm Conversion
Replies: 1
Views: 10

kPa to atm Conversion

For one of the sapling question I got this week, the pressure of the system was 7.00 kPa. What is the conversion of kPa to atm?
by SLai_1I
Sat Feb 06, 2021 10:13 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Systems
Replies: 24
Views: 87

Re: Systems

I think the universe would be an isolated system, since its energy stays constant. It can't gain or lose energy.
by SLai_1I
Sat Feb 06, 2021 10:12 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy vs Entropy
Replies: 7
Views: 35

Re: Enthalpy vs Entropy

Enthalphy is the net heat gained/lost in a system. Entropy is a measure of the disorder in the system and is based on its molecules.
by SLai_1I
Sat Feb 06, 2021 10:10 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: External Pressure
Replies: 32
Views: 63

Re: External Pressure

I think external pressure is the pressure acting on the system, so in your case it would be the pressure pushing down on the piston.
by SLai_1I
Sat Feb 06, 2021 10:07 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: deltaU
Replies: 29
Views: 106

Re: deltaU

Delta U is the change in internal energy of a system. It's equation is Delta U = Q + W
by SLai_1I
Sat Feb 06, 2021 10:05 pm
Forum: Student Social/Study Group
Topic: Silly Mistakes?
Replies: 60
Views: 301

Re: Silly Mistakes?

This was great to read after the midterm. Thank you!
by SLai_1I
Wed Feb 03, 2021 5:12 pm
Forum: Calculating Work of Expansion
Topic: Positive/Negative Work Value
Replies: 4
Views: 24

Positive/Negative Work Value

When work is positive, work is done on the system. When work is negative, work is done by the system. Is this statement true? If so, why is it true?
by SLai_1I
Sat Jan 30, 2021 10:40 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: isolated system
Replies: 9
Views: 49

Re: isolated system

Dr. Lavelle seemed to imply that we wouldn't be learning much about them. I don't think we are going to look into them too heavily.
by SLai_1I
Sat Jan 30, 2021 10:38 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar and Specific Heat Capacity
Replies: 6
Views: 36

Re: Molar and Specific Heat Capacity

Molar heat capacity is the heat need to heat 1 mol of a substance by 1 C. Specific heat capacity is the same but per gram rather per mol substance. The information given in the question will hint at which you should use.
by SLai_1I
Sat Jan 30, 2021 10:33 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: perfect system
Replies: 20
Views: 81

Re: perfect system

What Dr. Lavelle means by this is that a perfect system is when the heat in the reaction equal that of the surrounding. The equation can be rewritten as
qsys = -qsurr
by SLai_1I
Sat Jan 30, 2021 10:31 pm
Forum: Ideal Gases
Topic: Conditions
Replies: 20
Views: 69

Re: Conditions

STP conditions are 273 Kelvin and 1 atm.
by SLai_1I
Sat Jan 30, 2021 10:30 pm
Forum: Student Social/Study Group
Topic: Favorite TV shows
Replies: 197
Views: 1249

Re: Favorite TV shows

Breaking Bad is my favorite show of all time. Highly recommend it!
by SLai_1I
Sun Jan 24, 2021 3:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Justin Sarquiz Step-Up Question
Replies: 9
Views: 58

Justin Sarquiz Step-Up Question

What is the pH of a solution with 0.100 M nitrous acid, HNO2, and 0.150M potassium nitrite, KNO2?
Given Ka = 4.3 x 10^-4 for nitrous acid.

This question is from Justin's week 3 step-up session. I don't know where to start solving. What would be the equation for the reaction? Can anyone help?
by SLai_1I
Sat Jan 23, 2021 1:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1 Allowed Materials and Procedure
Replies: 6
Views: 52

Re: Midterm 1 Allowed Materials and Procedure

I'm pretty sure the midterm will be structured how it was for 14A where it was through the Respondus extension and we were allowed to have a calculator, periodic table, the equation sheet, and scratch paper.
by SLai_1I
Fri Jan 22, 2021 10:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating pH of Diprotic Acid Solutions
Replies: 3
Views: 16

Re: Calculating pH of Diprotic Acid Solutions

Alright that helps a lot. Thanks!
by SLai_1I
Fri Jan 22, 2021 8:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating pH of Diprotic Acid Solutions
Replies: 3
Views: 16

Calculating pH of Diprotic Acid Solutions

For calculating the pH of diprotic acid solutions, how do we know when to ignore the second deprotonations? One of the textbooks questions (6E.3) mentions this and I wasn't sure what it meant.
by SLai_1I
Tue Jan 19, 2021 6:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Comparing pKb Values
Replies: 4
Views: 13

Comparing pKb Values

In lecture, Dr. Lavelle went over the idea that the smaller the pKa value, the stronger the acid. Is this the same for bases, where the smaller the pKb, the stronger the base?
by SLai_1I
Tue Jan 19, 2021 3:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Question 6A21
Replies: 3
Views: 14

Textbook Question 6A21

This is a question from the textbook (6A. 21). Anyone know how to start doing it?

The value of Kw for water at body temperature (37 C) is 2.1*10^-14. (a) What is the molar concentration of H3O+ ions at
37 C? (b) What is the molar concentration of OH- in neutral water at 37 C?
by SLai_1I
Sun Jan 17, 2021 7:57 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 46
Views: 206

Re: Q and K

Yes, K can only be measured when the reactant is at equilibrium. Q, on the other hand, can be measured at any time of the reaction to determine the direction the reaction will continue.
by SLai_1I
Sun Jan 17, 2021 5:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling HW #5
Replies: 2
Views: 37

Re: Sapling HW #5

That's how I've been trying it but I keep getting the same wrong result :(
by SLai_1I
Sun Jan 17, 2021 5:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling HW #5
Replies: 2
Views: 37

Sapling HW #5

I've been stuck on this question from sapling for about half an hour now. I keep getting 63.8% but it's wrong. Can anyone help? The Kb for an amine is 5.542×10−5. What percentage of the amine is protonated if the pH of a solution of the amine is 9.557? Assume that all OH− came from the reaction of B...
by SLai_1I
Sun Jan 17, 2021 3:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5I #15
Replies: 4
Views: 39

Re: Textbook Problem 5I #15

Ahh I see it now. Thank you so much!
by SLai_1I
Fri Jan 15, 2021 4:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5I #15
Replies: 4
Views: 39

Textbook Problem 5I #15

When solid NH4HS and 0.400 mol NH3(g) were placed in a vessel of volume 2.0 L at 24 8C, the equilibrium NH4HS(s) ->NH3(g) + H2S(g), for which Kc=1.6*10^-4, was reached. What are the equilibrium concentrations of NH3 and H2S? Does anyone know how to do this problem? I think it's and ICE Table problem...
by SLai_1I
Sun Jan 10, 2021 9:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Part 3 Post Module Assessment #19
Replies: 4
Views: 31

Re: Part 3 Post Module Assessment #19

Ohh ok I see it now. Thanks guys.
by SLai_1I
Sun Jan 10, 2021 9:28 pm
Forum: Ideal Gases
Topic: Bars to atm [ENDORSED]
Replies: 41
Views: 246

Re: Bars to atm [ENDORSED]

Thank you everyone for all the responses! Appreciate it.
by SLai_1I
Wed Jan 06, 2021 11:33 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Part 3 Post Module Assessment #19
Replies: 4
Views: 31

Part 3 Post Module Assessment #19

Does anyone know how to do this question? I've tried 3 times and keep getting 2.45*10^-9 as my answer. Please let me know! Calculate the reaction quotient, QC, from the following equilibrium data collected in a 3.00 L sealed reaction vessel for the reaction: AsH3 (g) ⇌ As (s) + H2 (g) AsH3 = 5.55 x ...
by SLai_1I
Tue Jan 05, 2021 2:27 pm
Forum: Ideal Gases
Topic: Bars to atm [ENDORSED]
Replies: 41
Views: 246

Bars to atm [ENDORSED]

When talking about units of pressure, what is the conversion from bars to atm, or vice versa.
by SLai_1I
Tue Jan 05, 2021 2:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Module Assessment #15
Replies: 4
Views: 30

Post Module Assessment #15

This question is from the post module assessment for part 2 of chemical equilibrium. I can't seem to get any of the given answer choices. Can someone help? Carbonyl chloride (COCl2 ), also called phosgene, was used in World War I as a poisonous gas. The equilibrium concentrations for the reaction be...
by SLai_1I
Sat Dec 12, 2020 5:26 pm
Forum: Hybridization
Topic: Why do we apply Hybridization Schemes?
Replies: 2
Views: 24

Why do we apply Hybridization Schemes?

I am going through past UA worksheets to study and found this question from Matthew's Week 8 Workshop. Does anyone know the answer? In the ground state, nitrogen has 3 unpaired electrons. Nitrogen normally forms 3 covalent bonds (e.g. NH 3 ). Why do we have to apply a hybridization scheme for nitrog...
by SLai_1I
Sat Dec 12, 2020 5:21 pm
Forum: Bronsted Acids & Bases
Topic: metal/nonmetal oxides
Replies: 3
Views: 22

Re: metal/nonmetal oxides

Yes, we need to know that metal oxides are basic and that nonmetal oxides are acidic. I'm not too sure why this is the case, but it is easy to memorize.
by SLai_1I
Sat Dec 12, 2020 5:19 pm
Forum: Polyprotic Acids & Bases
Topic: Polyprotic Acids
Replies: 6
Views: 49

Re: Polyprotic Acids

Yes, as everyone else is saying, polyphonic acids are acids that can donate multiple hydrogens.
by SLai_1I
Thu Dec 10, 2020 6:16 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands
Replies: 2
Views: 42

Polydentate Ligands

Are carbonato (CO3^2-) and sulfato (OSO3^2-) polydentate ligands? If so, what kind of polydentate are they?
by SLai_1I
Thu Dec 10, 2020 12:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: LiCl vs. NaCl Boiling Point
Replies: 1
Views: 29

LiCl vs. NaCl Boiling Point

Can anyone help explain why the boiling point of NaCl is higher than that of LiCl? Since Li+ has a stronger polarizing power than Na+ (because Li+ is a smaller cation), wouldn't that mean that LiCl has stronger LDF's than NaCl? Please let me know if I'm understanding this wrong!
by SLai_1I
Thu Dec 10, 2020 12:13 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: pKa
Replies: 3
Views: 36

Re: pKa

I don't think so. However, I think we should know how pKa and Ka trend though: smaller pKa=stronger acid, higher Ka=stronger acid.
by SLai_1I
Sat Dec 05, 2020 6:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 21
Views: 164

Re: Final

As everyone else is saying, I think the final will be conducted similarly to the midterms. If anything changes, I'm sure we'll be informed.
by SLai_1I
Sat Dec 05, 2020 6:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Extra Credit
Replies: 13
Views: 155

Re: Extra Credit

I don't think Lavelle offers extra credit :(
by SLai_1I
Fri Dec 04, 2020 7:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook Question 9C:5
Replies: 2
Views: 18

Textbook Question 9C:5

I was going through the textbook problems for the coordination compounds section and had trouble with problems 5b. and 5d. How can CO3 2- sometimes be bidentate, and how is oxalate bidentate? Please help if you can!
by SLai_1I
Fri Dec 04, 2020 7:32 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands
Replies: 3
Views: 31

Polydentate Ligands

What are ways to tell if a ligand is polydentate?
by SLai_1I
Thu Dec 03, 2020 2:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Chart
Replies: 4
Views: 59

VSEPR Chart

Does anyone have a link to a good chart for the VSEPR Model shapes and polarities?
by SLai_1I
Sat Nov 28, 2020 3:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape vs Polarity
Replies: 11
Views: 73

Re: Shape vs Polarity

From my understanding, the electron density structure is determined by the number of electron density regions around the central atom. The molecular shape, on the other hand, is determined by the number of lone pairs, bonds, and positioning of the atoms. Not one hundred percent sure though.
by SLai_1I
Sat Nov 28, 2020 2:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining shape with lone pairs
Replies: 5
Views: 32

Re: Determining shape with lone pairs

From my understanding, you should try to place the lone pair as far away from other lone pairs and then bonds. This is because of the repulsion strength Lavelle mentioned: lone-lone pair > lone-bond pair > bond-bond pair.
by SLai_1I
Sat Nov 28, 2020 1:54 pm
Forum: Lewis Structures
Topic: lewis structure resonance
Replies: 5
Views: 44

Re: lewis structure resonance

They technically aren't incorrect, but having correct formal charges is ideal and what would most likely occur in nature.
by SLai_1I
Sat Nov 28, 2020 1:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Double/Triple Bonds and Polarity
Replies: 8
Views: 61

Re: Double/Triple Bonds and Polarity

I think it may affected polarity slightly, but the main factor of polarity is electronegativity.
by SLai_1I
Sat Nov 28, 2020 1:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity and Shape
Replies: 13
Views: 107

Re: Polarity and Shape

Knowing how to draw Lewis Structures would help you get by without having to memorize structures. You could draw the dipoles on the Lewis Structure and see if they cancel out.
by SLai_1I
Sat Nov 28, 2020 1:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 15
Views: 154

Re: Final

I think Dr. Lavelle will tell us more about the procedures and how testing will work as we get closer to the actual date.
by SLai_1I
Sat Nov 28, 2020 1:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Final
Replies: 15
Views: 154

Re: Final

I think Dr. Lavelle will tell us more about the procedures and how testing will work as we get closer to the actual date.
by SLai_1I
Sat Nov 28, 2020 1:44 pm
Forum: Student Social/Study Group
Topic: Midterm/Final Success?
Replies: 17
Views: 148

Re: Midterm/Final Success?

As others have mentioned, I find the UA zoom meetings particularly helpful. In the meetings, the UA's will usually send out a worksheet with relevant topics for you to work on. They go over the answers step by step and the process really helps with understanding what is covered in lectures. I also l...
by SLai_1I
Tue Nov 17, 2020 10:31 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability of Anions and Cations
Replies: 6
Views: 48

Polarizability of Anions and Cations

How do the polarizability of anions and cations differ? Is there a general trend that polarizability follows on the periodic table?
by SLai_1I
Tue Nov 17, 2020 6:46 pm
Forum: Bond Lengths & Energies
Topic: IMF vs. Intramolecular Forces
Replies: 7
Views: 68

IMF vs. Intramolecular Forces

When asked to compare the strength molecules, how do we know if the question is referring to IMFs or Intramolecular forces? For example, which molecule is stronger, I2 or F2? F2 has a smaller atomic radius, so its intramolecular forces would be stronger. However, I2 has more electrons, so its LDFs a...
by SLai_1I
Mon Nov 16, 2020 5:08 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 31
Views: 327

Re: Midterm 2

Does anyone know exactly how long Midterm 2 will be?
by SLai_1I
Sat Nov 14, 2020 3:06 pm
Forum: Ionic & Covalent Bonds
Topic: Cation vs Anion
Replies: 5
Views: 68

Re: Cation vs Anion

When an anion is formed, the atom of the anion gains an electron (could be more than one) to reach noble gas configuration. This gives the anion a negative charge.
by SLai_1I
Sat Nov 14, 2020 3:04 pm
Forum: Administrative Questions and Class Announcements
Topic: What's going to be on the midterm?
Replies: 3
Views: 18

Re: What's going to be on the midterm?

Everything we learned that wasn't on the previous midterm, up until what we learned on Wednesday. VESPR isn't going to be included from what I've heard.
by SLai_1I
Wed Nov 11, 2020 1:05 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 31
Views: 327

Re: Midterm 2

Does anyone know if Midterm 2 is going to include subjects that were tested on Midterm 1? Or is it just new, untested material?
by SLai_1I
Wed Nov 11, 2020 1:02 pm
Forum: Lewis Structures
Topic: Hydrogen in Lewis Structures
Replies: 5
Views: 37

Re: Hydrogen in Lewis Structures

Because hydrogen only has a 1s orbital, it can hold a maximum of 2 electrons, nothing more.
by SLai_1I
Wed Nov 11, 2020 1:01 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidization Numbers
Replies: 10
Views: 80

Re: Oxidization Numbers

I was also kind of confused when I saw that it was in sapling as well. I would just review and look over it before the midterm just in case. It wouldn't hurt.
by SLai_1I
Sat Nov 07, 2020 2:16 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge of the Same Element
Replies: 15
Views: 67

Re: Formal Charge of the Same Element

No, as each reply has stated, each atom has its own formal charge. Even though there could be 2 of the same element in a lewis structure, their formal charges are dependent on the amount of bonds and lone pairs they are connected to. This could result in 2 atoms of the same element having different ...
by SLai_1I
Fri Nov 06, 2020 8:00 pm
Forum: Resonance Structures
Topic: Stability and Delocalized Electrons
Replies: 3
Views: 25

Stability and Delocalized Electrons

Why are structures with delocalized electrons more stable than structures without them?
by SLai_1I
Fri Nov 06, 2020 11:04 am
Forum: Ionic & Covalent Bonds
Topic: Atomic Radius
Replies: 38
Views: 260

Re: Atomic Radius

As you move across a period, more protons are being added to the nucleus, increasing the atomic number. This makes the nucleus more positive, giving it a stronger pull on the valence electrons, decreasing the atomic radius.
by SLai_1I
Wed Nov 04, 2020 6:38 pm
Forum: Octet Exceptions
Topic: Limit on Expanding Octet
Replies: 2
Views: 24

Limit on Expanding Octet

Is there a limit to the amount of valence electrons that can fit onto an expanded octet? If so, what is it?
by SLai_1I
Wed Nov 04, 2020 10:40 am
Forum: Resonance Structures
Topic: Delocalized Electrons
Replies: 2
Views: 31

Delocalized Electrons

In the resonance structure lecture, Dr. Lavelle says that electrons are delocalized in resonance structures. What does it mean when electrons are delocalized? How is it different from when they are localized?
by SLai_1I
Fri Oct 30, 2020 3:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Practice Exams
Replies: 8
Views: 105

Re: Practice Exams

Sorry this is kinda late, but a workshop I went to last week included problems from past exams. I would recommend going to those to prepare for future exams.
by SLai_1I
Fri Oct 30, 2020 3:15 pm
Forum: *Shrodinger Equation
Topic: Midterm Scores
Replies: 30
Views: 349

Re: Midterm Scores

I think everyone will finish by tonight, so hopefully soon. I read that someone mentioned something about partial credit. How would that work?
by SLai_1I
Fri Oct 30, 2020 10:27 am
Forum: *Shrodinger Equation
Topic: New Audio-Visual Modules
Replies: 9
Views: 104

New Audio-Visual Modules

Does anyone know if Dr. Lavelle will be posting new Audio-Visual topics on his website after the midterm? I found those really helpful and would appreciate it if they were updated.
by SLai_1I
Tue Oct 27, 2020 11:45 am
Forum: Photoelectric Effect
Topic: Photoelectric Effect Equation
Replies: 2
Views: 55

Photoelectric Effect Equation

Can EK's (the energy of the ejected electron in the photoelectric effect) properties like wavelength and frequency be found using the E=hv equation? Or do you have to use EK=(1/2)mv^2 and DeBrogile's equation?
by SLai_1I
Tue Oct 27, 2020 11:41 am
Forum: *Shrodinger Equation
Topic: Shrodinger Equation on Midterm 1
Replies: 3
Views: 78

Shrodinger Equation on Midterm 1

How much of Schrodinger's Equation should we know for the midterm? Are there any calculations to go along with it?
by SLai_1I
Sat Oct 24, 2020 7:47 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Problem
Replies: 6
Views: 67

Photoelectric Effect Problem

Hi, I got this question from a workshop worksheet, but forgot to write down the correct answer. Can somebody solve this and let me know what they get so I can check mine? Thanks! If the wavelength of incident light on sodium metal was 810 nm, and the work function of sodium is 1.1 eV, what is the wa...
by SLai_1I
Fri Oct 23, 2020 10:15 am
Forum: *Shrodinger Equation
Topic: Light Experiment/Equation Clarification
Replies: 3
Views: 44

Light Experiment/Equation Clarification

Hi, can anyone tell me which experiments/equations show light behaves like a wave, and which experiments/equations show light behaves as a particle? I keep getting them mixed up.
by SLai_1I
Wed Oct 21, 2020 10:34 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Showing Work for Heisenberg Indeterminacy Equation
Replies: 2
Views: 30

Showing Work for Heisenberg Indeterminacy Equation

When using the Heisenberg Indeterminacy Equation to solve problems, when are you supposed to use an equal sign rather than an inequality symbol?
by SLai_1I
Tue Oct 20, 2020 5:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sapling HW Weeks 2-4 #6
Replies: 1
Views: 22

Sapling HW Weeks 2-4 #6

The electron in a hydrogen atom is excited to the n=6 shell and emits electromagnetic radiation when returning to lower energy levels. Determine the number of spectral lines that could appear when this electron returns to the lower energy levels, as well as the wavelength range in nanometers. How do...
by SLai_1I
Mon Oct 19, 2020 2:20 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Problem 1B27
Replies: 6
Views: 51

Textbook Problem 1B27

A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 plus/minus 5.0 m*s^-1. What is the minimum uncertainty in its position? What is the delta V for this problem? I keep rereading the question, and it seems to be 10 m/s. However, when I use this value, I get the wrong answer. T...
by SLai_1I
Mon Oct 19, 2020 10:48 am
Forum: DeBroglie Equation
Topic: DeBrogile Equation Derivation
Replies: 1
Views: 55

DeBrogile Equation Derivation

In today's lecture, Dr. Lavelle went over how DeBrogile came up with the equation. Will we need to remember how he did this in the future?
by SLai_1I
Fri Oct 16, 2020 3:16 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 4
Views: 35

Re: Wave Properties of Electrons

When waves interact destructively, one wave's troughs interact with another's peaks, and the peaks interact with the other wave's troughs. The waves combine and the result is a waved with a reduced amplitude, one that is "canceled out". Sorry, my explanation is kind of confusing. I've foun...
by SLai_1I
Fri Oct 16, 2020 3:12 pm
Forum: Properties of Light
Topic: Intensity v Energy
Replies: 18
Views: 167

Re: Intensity v Energy

You are understanding correctly! A change in amplitude/intensity will not affect the E=hv equation.
by SLai_1I
Fri Oct 16, 2020 3:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post Module #28
Replies: 1
Views: 33

Re: Atomic Spectra Post Module #28

With the given information, you can set 1 meter=1,650,763.73 wavelengths. If you divide both sides by 1,650,763.73, you will end up with 1 wavelength=6.06*10^-7 meters. This wavelength lies in the visible light section of the electromagnetic spectrum. You can then take this value to find the energy ...
by SLai_1I
Thu Oct 15, 2020 8:12 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty Equation Post-Module Assessment #23
Replies: 4
Views: 51

Heisenberg Uncertainty Equation Post-Module Assessment #23

23. You are caught in a radar trap and hope to show that the speed measured by the radar gun is in error due to the Heisenberg uncertainty principle. If you assume that the uncertainty in your position was +/- 5 m when your speed was measured, and that the car has a mass of 2150 kg, what is your cal...
by SLai_1I
Thu Oct 15, 2020 7:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty Equation Post-Module Assessment #20
Replies: 3
Views: 41

Heisenberg Uncertainty Equation Post-Module Assessment #20

20. Use the above uncertainty in velocity to calculate the electron's uncertainty in kinetic energy. Then calculate the uncertainty in kinetic energy per mole of electrons (that is, per mole of hydrogen atoms). Comment on your value. Does anyone know how to do this question? I can solve for the unce...
by SLai_1I
Mon Oct 12, 2020 4:39 pm
Forum: Photoelectric Effect
Topic: Energy of photons
Replies: 5
Views: 55

Re: Energy of photons

Wavelength and frequency are inversely related. This means that raising one will lower the other. When the energy if the photon is increased, two things are happening. Frequency is being raised, and wavelength is being reduced.

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