Search found 101 matches

by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:31 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration Cells
Replies: 8
Views: 98

Re: Concentration Cells

Daniel Chen 2L wrote:But doesn't the concentrations of the reactants and products in a concentration cell have to be different in order to generate voltage?


I think in a concentration cell the two electrodes are composed of the same solution, but they differ in concentration so voltage will be generated.
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:28 am
Forum: Balancing Redox Reactions
Topic: Balancing redox with h2o
Replies: 9
Views: 102

Re: Balancing redox with h2o

So adding h2o, h3o+, and oh- balances the charge and elements or do you then have to add certain elements? Are you limited to just those 3? If elements other than H and O need to be balanced in the equation you should use coefficients, but when you balance a redox reaction the only things being add...
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:25 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ignoring solids & liquids for K
Replies: 7
Views: 118

Re: ignoring solids & liquids for K

ursulavictorino1K wrote:So an aqueous solution isn't considered a liquid?


No, only pure liquids (l) and solids (s) are exempt from calculating k. Aqueous solutions describe a solution or mixture containing a solute dissolved in a solvent which is water.
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What to do if R>P for two equations
Replies: 4
Views: 87

Re: What to do if R>P for two equations

You should calculate Q and K and if Q < K then the reaction is product favored and will shift to the right
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:16 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Water and voltage
Replies: 3
Views: 113

Re: Water and voltage

I think if the amount of water that is added is given then you can use that value to recalculate the concentration of the solution the water is added to. If the concentration of the solution is changed then there will be a change in the voltage
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:14 am
Forum: Balancing Redox Reactions
Topic: Reversing the anode
Replies: 10
Views: 114

Re: Reversing the anode

ursulavictorino1K wrote:If they are always given as recutions, How do you know which to flip to an oxidizer?


If they give you the cell potentials of each reaction, the reaction with the lower cell potential is the one that is oxidized so it will be flipped
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:11 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidizer vs reducer
Replies: 3
Views: 63

Re: Oxidizer vs reducer

If they provide you with the cell potentials of each reaction, the reaction with the lower cell potential is the one that is oxidized.
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:10 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2 deltaG equations
Replies: 1
Views: 62

Re: 2 deltaG equations

They both solve for the same delta G. You could also set these two equations equal to each other to derive the Van't Hoff Equation
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:09 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Ecell vs Eocell
Replies: 2
Views: 61

Re: Ecell vs Eocell

Ecell is the cell potential, whereas Eocell is the standard cell potential which is measured at standard conditions, such as 1 atm, 25 degrees celsius
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:06 am
Forum: Balancing Redox Reactions
Topic: Switching the anode reaction
Replies: 1
Views: 55

Re: Switching the anode reaction

Usually in the problems they give the equations as gaining electrons (so the electrons are added to the left side of the equation), but anode's are oxidized which means electrons are lost, so the electrons should be on the right side of the equation which is why they flip the anode reaction.
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:05 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Increasing voltage of a cell
Replies: 3
Views: 64

Re: Increasing voltage of a cell

Changing the concentration of one solution in an electrode may affect the voltage of a cell
by Jiyoon_Hwang_2I
Tue Mar 17, 2020 6:01 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Surface area and voltage
Replies: 1
Views: 48

Re: Surface area and voltage

Surface area does not affect the voltage of a cell because the voltage is affected by the electrodes, not the amount of material
by Jiyoon_Hwang_2I
Mon Mar 16, 2020 4:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: adding platinum
Replies: 8
Views: 74

Re: adding platinum

Does the inert metal always have to be platinum? How do you know when to use platinum or any other inert metal?
by Jiyoon_Hwang_2I
Mon Mar 16, 2020 4:54 pm
Forum: Administrative Questions and Class Announcements
Topic: final grades
Replies: 12
Views: 217

Re: final grades

I think he'll post final grades this Thursday because he said he would post Chemistry Community grades on Thursday.
by Jiyoon_Hwang_2I
Mon Mar 16, 2020 4:52 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Return
Replies: 20
Views: 239

Re: Test 2 Return

What if we live out of state and still haven't gotten our Test 2 back...?
by Jiyoon_Hwang_2I
Mon Mar 16, 2020 4:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Grades
Replies: 6
Views: 140

Re: Final Grades

^^ I agree. The fact that he said he would upload chemistry community grades on thursday I'm assuming means he's going to upload all the other grades too. Especially since the final was multiple choice it shouldn't take long for him to grade and upload
by Jiyoon_Hwang_2I
Mon Mar 16, 2020 4:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Community Posts Due Date
Replies: 13
Views: 238

Re: Chem Community Posts Due Date

He said he's going to take the number of posts you have by wednesday and you should see your chemistry community grade up by thursday!!
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:41 pm
Forum: Calculating Work of Expansion
Topic: Integral
Replies: 2
Views: 54

Re: Integral

Because if pressure is not changing the only thing changing is volume
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic and voltaic cells
Replies: 5
Views: 67

Re: Galvanic and voltaic cells

Galvanic and voltaic cells are the same. The names are interchangeable
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:36 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: nernst
Replies: 2
Views: 59

Re: nernst

E is an intensive property so it doesn’t depend on the amount of substances involved so multiplying the reaction equation does not multiply E
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:34 pm
Forum: Calculating Work of Expansion
Topic: reversible expansion
Replies: 4
Views: 58

Re: reversible expansion

The area under the curve usually represent work
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Final Typo
Replies: 8
Views: 249

Re: Chem Final Typo

Yes. I think it should have been x10^4
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:32 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius eq
Replies: 5
Views: 56

Re: Arrhenius eq

You should use the Arrhenius Equation when determining the effect of a change in temperature on the rate constant
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:29 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: adiabatic processes
Replies: 1
Views: 49

Re: adiabatic processes

I think you just have to know that Q = 0 for adiabatic processes so when you use any thermodynamics equation set Q equal to zero and solve
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:25 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Deriving the equation
Replies: 4
Views: 62

Re: Deriving the equation

You should use the two equations for delta G and set them equal to each other. So set delta G = delta G(standard) + RTlnQ equal to delta G=-nFE
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: lnQ
Replies: 4
Views: 64

Re: lnQ

Yes! The coefficients represent the power the concentrations are raised to
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:22 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: temp vs k
Replies: 3
Views: 42

Re: temp vs k

As temperature increases the rate constant should increase
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:20 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes of Concentration Cell
Replies: 3
Views: 56

Re: Electrodes of Concentration Cell

The cathode is always the negative electrode
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Athena
Replies: 34
Views: 1825

Re: Athena

Thank you for a wonderful quarter! I hope you are able to get some rest over break.
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:18 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: steady state v preeq
Replies: 4
Views: 57

Re: steady state v preeq

For steady state, the first step of the reaction must be slower than the second step. On the other hand, for pre-equilibrium, the first step must be faster than the second step. how do you know which step is the fast step and which is the slow step Im not exactly sure either but sometimes they will...
by Jiyoon_Hwang_2I
Sun Mar 15, 2020 1:17 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pH of acids
Replies: 11
Views: 220

Re: pH of acids

Weak acids have higher pH because they’re essentially closer to 7 (neutral pH) and strong acids are on the farther side of the pH spectrum which is why they have a lower pH
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 7:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: ENDGAME Q.10
Replies: 3
Views: 42

Re: ENDGAME Q.10

I think when you use the equation E cell = E cathode - E anode you don't use the flipped cell potentials. Instead, you use the cell potentials that were given in the table so it would be E = 1.23 - 0.80 = 0.43. Otherwise you can add 1.23 + (-0.80) which is also 0.43
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 7:03 pm
Forum: Balancing Redox Reactions
Topic: balancing h and o
Replies: 7
Views: 93

Re: balancing h and o

But you should be careful of whether they're asking you to balance the equation in acidic or basic conditions because the way you balance H is different for both conditions
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 6:36 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: solubility product
Replies: 1
Views: 22

Re: solubility product

When solving for the solubility product, it is similar to finding the equilibrium constant, k, but only the concentration of the ions are included in the solubility product
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 6:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 275
Views: 130231

Re: Saying Thank You to Dr. Lavelle

Thank you so much Dr. Lavelle!! I am so so soooo glad I was able to take both Chem 14A and Chem 14B with you! I really appreciated your quick email updates and the effort you put in to allow your students to succeed in the course. I'm sure this situation with finals becoming online was stressful for...
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 6:27 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy
Replies: 6
Views: 94

Re: Internal Energy

The internal energy is 0 because isothermal means the temperature is constant
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 5:22 pm
Forum: Zero Order Reactions
Topic: units of k
Replies: 5
Views: 77

Re: units of k

Its because some of the concentrations are squared or cubed so the units are also squared/cubed
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 5:19 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: pseudo rate law
Replies: 3
Views: 45

Re: pseudo rate law

In a pseudo rate law you assume that the other reactants are in large excess and you measure the isolated reactant
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 5:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Where to find the final exam
Replies: 5
Views: 48

Re: Where to find the final exam

He actually just sent an email out saying that it will be on CCLE. Theres going to be 6 questions with multiple parts and each question will be about 5 points and the final is a total of 180 points
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 5:07 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Endgame #5 [ENDORSED]
Replies: 2
Views: 103

Re: Endgame #5 [ENDORSED]

I think n is 1 electron instead of 2 because the question asked for the Ka of HF and not 2HF
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 5:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Partial Credit?
Replies: 3
Views: 69

Re: Final Partial Credit?

I don't think we'll get partial credit for our work. I think the final might be short answer so you fill in the answer instead of it being multiple choice, but there may be some multiple choice questions like there were on the midterm.
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 4:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Online Final
Replies: 3
Views: 60

Online Final

How are we showing our work if the final is on CCLE?
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 4:56 pm
Forum: Administrative Questions and Class Announcements
Topic: ENDGAME Review Session
Replies: 71
Views: 2528

Re: ENDGAME Review Session

Can someone explain why E=0 for question 5?
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 4:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading Scale
Replies: 14
Views: 244

Re: Grading Scale

Everything is worth 50 points except the midterm which is worth 120 points and the final which is worth 180 points so the entire course is 500 points
by Jiyoon_Hwang_2I
Sat Mar 14, 2020 4:52 pm
Forum: General Science Questions
Topic: Who makes the Final
Replies: 23
Views: 287

Re: Who makes the Final

The TAs dont even get to see the answer key until about one hour before we take the test.
by Jiyoon_Hwang_2I
Mon Mar 09, 2020 4:06 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: steady state v preeq
Replies: 4
Views: 57

Re: steady state v preeq

For steady state, the first step of the reaction must be slower than the second step. On the other hand, for pre-equilibrium, the first step must be faster than the second step.
by Jiyoon_Hwang_2I
Mon Mar 09, 2020 4:02 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts and Equilibrium
Replies: 2
Views: 14

Re: Catalysts and Equilibrium

Catalysts don't affect the equilibrium because they speed up the forward and reverse reaction rates equally.
by Jiyoon_Hwang_2I
Mon Mar 09, 2020 4:01 pm
Forum: General Science Questions
Topic: Final
Replies: 7
Views: 127

Re: Final

I am not sure if there will be a lot of questions on it, but I would still study it sufficiently because 14A's final did not have a lot on acids and bases so it might be possible that 14B has more.
by Jiyoon_Hwang_2I
Sun Feb 23, 2020 3:47 pm
Forum: Balancing Redox Reactions
Topic: spontaneous
Replies: 15
Views: 129

Re: spontaneous

A positive standard reduction potential represents a spontaneous reduction reaction.
by Jiyoon_Hwang_2I
Sun Feb 23, 2020 3:45 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Concentration and cell potential
Replies: 6
Views: 53

Re: Concentration and cell potential

Changing the concentration of a solution will increase the concentration gradient between the two solutions, causing the voltage potential to increase. Since the two solutions are further away from equilibrium, Le Chatelier's principle will be implemented to bring the two solutions back to equilibri...
by Jiyoon_Hwang_2I
Sun Feb 23, 2020 3:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 9
Views: 61

Re: Salt Bridge

The purpose of the salt bridge is to maintain the neutral charge in the solutions as electrons flow between the two solutions.
by Jiyoon_Hwang_2I
Sun Jan 12, 2020 10:26 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: The concept of Gibbs Free Energy
Replies: 4
Views: 37

Re: The concept of Gibbs Free Energy

Gibbs Free Energy tells you the maximum amount of work that can be done under a system with constant temperature and pressure.
by Jiyoon_Hwang_2I
Sun Jan 12, 2020 10:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids and liquids
Replies: 5
Views: 37

Re: solids and liquids

Solids and liquids are pure and they don't affect the reactant amount so they are omitted from the equilibrium expression. Also, the concentrations of these pure solids and liquids are calculated by dividing their density by molar mass and their density remains constant regardless of the amount of p...
by Jiyoon_Hwang_2I
Sat Jan 11, 2020 6:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to do ice tables [ENDORSED]
Replies: 4
Views: 44

Re: When to do ice tables [ENDORSED]

If the questions provides you with initial concentrations and asks you to solve for the equilibrium compositions you should use the ICE table.
by Jiyoon_Hwang_2I
Sat Jan 11, 2020 9:36 am
Forum: Ideal Gases
Topic: textbook [ENDORSED]
Replies: 2
Views: 28

Re: textbook [ENDORSED]

Yes! It is the same textbook
by Jiyoon_Hwang_2I
Sat Jan 11, 2020 9:35 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Problem 5i.11- using molarity in place of pressure?
Replies: 3
Views: 38

Re: Problem 5i.11- using molarity in place of pressure?

I think you use the concentrations instead of the partial pressures because the given value of K is Kc and they are asking you for Qc so you should keep it consistent by using concentrations instead of partial pressures.
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:32 am
Forum: Calculating the pH of Salt Solutions
Topic: 6D.11 (d)
Replies: 2
Views: 84

Re: 6D.11 (d)

I think it is because Br- is a conjugate base of HBr which is a strong acid therefore Br- is a weak base and weak bases do not affect the pH and K+ is a conjugate acid of strong base KOH so it will also not affect the pH
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:25 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: enthalpy?
Replies: 3
Views: 35

Re: enthalpy?

I don't think so. We technically only need to know up to 6C and one section in 6D.3 and one in 6E.1
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:20 am
Forum: Biological Examples
Topic: Well-Known Examples of Chemo Drugs
Replies: 1
Views: 100

Re: Well-Known Examples of Chemo Drugs

I think the only one he talked about was cisplatin
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:19 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.1
Replies: 2
Views: 63

Re: 6B.1

I think it's because they're using the log rule that when you do log x - log y you can also write it as log (x/y) and in this problem they were finding the change in pH so they were doing log(final) - log(initial). So, the final would be 0.12 x [HCl]o and the initial is just [HCl]o
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:14 am
Forum: Naming
Topic: NH4[PtCl3(NH3)]
Replies: 5
Views: 119

Re: NH4[PtCl3(NH3)]

It is platinate because the coordination compound [Pt(Cl3)(NH3)] has an overall -1 charge and when there is a negative charge on the coordination compound, the metal name changes to -ate at the end.
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:12 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong acids and bases
Replies: 1
Views: 40

Re: strong acids and bases

For strong bases you should know that group 1 and group 2 oxides and hydroxides from strong bases. For strong acids HI, HCl, HBr, HClO4, HClO3, H2SO4, HNO3
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:09 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate
Replies: 4
Views: 141

Re: polydentate

In order for a ligand to be polydentate it must have on or more lone pairs because it has to have a lone pair to donate
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:06 am
Forum: Amphoteric Compounds
Topic: Methods to identify whether it's Amphoteric, basic or acidic
Replies: 1
Views: 87

Re: Methods to identify whether it's Amphoteric, basic or acidic

You can identify if a molecule is basic if it accepts a proton (H+) and if it is acidic it will lose/donate one of its protons. On the other hand, it can be amphoteric if it can both accept and donate a proton. So, H2O is amphoteric because it can accept a proton to become H3O+ or it can lose a prot...
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:02 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: List of Strong Acids and Weak Acids
Replies: 2
Views: 92

Re: List of Strong Acids and Weak Acids

You should know the main strong acids, such as HI, HCl, HBr, HNO3, etc
by Jiyoon_Hwang_2I
Sun Dec 08, 2019 3:00 am
Forum: Biological Examples
Topic: EDTA
Replies: 3
Views: 98

Re: EDTA

EDTA is ethylenediaminetetraaceto and it is a chelate that removes metals from solutions. For example, edta may be prescribed to remove toxic metals, such as lead, from the blood.
by Jiyoon_Hwang_2I
Sun Nov 24, 2019 4:08 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE
Replies: 6
Views: 127

Re: AXE

I think it just helps you to picture the shape of the molecule, including the number of lone pair electrons to determine the shape. I am not 100% sure if it serves any other purpose, but typically I think its just used to determine the shape.
by Jiyoon_Hwang_2I
Sun Nov 24, 2019 4:06 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Octahedral
Replies: 2
Views: 43

Re: Octahedral

If the coordination compound has 6 ligands then it will be an octahedral complex, but not all of them have 6 ligands. Some can have 4 ligands which means it can be a tetrahedral complex or square-planar complex.
by Jiyoon_Hwang_2I
Sun Nov 24, 2019 4:03 pm
Forum: Naming
Topic: Coordination number
Replies: 7
Views: 57

Re: Coordination number

A coordination compound is formed when a ligand (a molecule or ion) forms coordinate covalent bonds with the central atom which is usually a transition metal. The coordination number of the coordination compound is determined by the number of bonds the central atom forms with the ligands. For exampl...
by Jiyoon_Hwang_2I
Sun Nov 24, 2019 3:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand
Replies: 4
Views: 40

Re: Ligand

Ligands are ions or molecules that are attached to the central metal atom. They usually have one or more lone pair electrons that bind to the central atom to form a coordinate covalent bond.
by Jiyoon_Hwang_2I
Sun Nov 24, 2019 3:52 pm
Forum: Naming
Topic: 9C.3
Replies: 2
Views: 59

Re: 9C.3

I'm not 100% sure if you'll have to memorize the table, but I think it'd be good to know the general rules. For example, if a complex has a negative charge add -ate to the end of the metal name. Also, add -o to the end of the anion name (i.e. F- is fluoride, but add an -o cuz its an anion and it bec...
by Jiyoon_Hwang_2I
Sun Nov 17, 2019 6:33 pm
Forum: Empirical & Molecular Formulas
Topic: Can someone check this answer?
Replies: 2
Views: 142

Re: Can someone check this answer?

I actually got C4H8O. First, I used the grams of CO2 given to determine the grams of carbon. Next, I used the grams of H2O to determine the grams of hydrogen. Then, add these values together and subtract from 2.00 g of the sample compound to determine how many grams of oxygen there are. Afterwards, ...
by Jiyoon_Hwang_2I
Sun Nov 17, 2019 6:26 pm
Forum: Hybridization
Topic: Sigma and Pi bonds
Replies: 2
Views: 27

Re: Sigma and Pi bonds

You can think of sigma bonds as basically a single bond. So, if two atoms have a single bond between them that means it has one sigma bond. On the other hand, every other bond after the single bond is considered a pi bond. For example, a double bond is a sigma bond and 1 pi bond and a triple bond is...
by Jiyoon_Hwang_2I
Sun Nov 17, 2019 6:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion
Replies: 2
Views: 32

Re: Repulsion

Usually, lone pairs cause more repulsion, so the bond angle decreases. For example, NH3 has 1 lone pair on nitrogen and its bond angle is 107 degrees, but H2O has 2 lone pairs and the bond angle is 104.5 degrees. So, the more lone pair electrons on the central atom, the more repulsion, causing the b...
by Jiyoon_Hwang_2I
Sun Nov 17, 2019 6:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dispersion
Replies: 5
Views: 62

Re: Dispersion

Dr. Lavelle briefly introduced induced dipole-induced dipole during one of his lectures last week so I think it'd be good to go over it. However, london dispersion forces, dipole-dipole, and hydrogen bonds were emphasized more so you should def know these more in depth.
by Jiyoon_Hwang_2I
Sun Nov 17, 2019 6:04 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable vs polarizing power
Replies: 5
Views: 154

Re: Polarizable vs polarizing power

Polarizable means an atom's electron cloud can be easily distorted by the strong pull of another atom. On the other hand, polarizing power means an atom has enough charge to cause distortion to another atom's electron cloud. I think it doesn't necessarily mean polarizability is only related to anion...
by Jiyoon_Hwang_2I
Sun Nov 10, 2019 7:55 pm
Forum: Electronegativity
Topic: dipole moments
Replies: 7
Views: 50

Re: dipole moments

Yes. The larger the difference in electronegativity, the larger the dipole moment.
by Jiyoon_Hwang_2I
Sun Nov 10, 2019 7:54 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability
Replies: 2
Views: 41

Re: polarizability

Polarizability tends to decrease from left to right on the periodic table and increases going down the periodic table.
by Jiyoon_Hwang_2I
Sun Nov 10, 2019 7:52 pm
Forum: Dipole Moments
Topic: arrows for dipole moments
Replies: 3
Views: 31

Re: arrows for dipole moments

The arrows are usually pointed towards the more electronegative atom (or the atom with the partially negative charge)
by Jiyoon_Hwang_2I
Sun Nov 10, 2019 7:51 pm
Forum: Coordinate Covalent Bonds
Topic: coordinate covalent bond
Replies: 9
Views: 206

Re: coordinate covalent bond

There is a coordinate covalent bond between NH3 and BF3. The bond between the nitrogen and boron is a coordinate covalent bond because both electrons come from the nitrogen atom.
by Jiyoon_Hwang_2I
Sun Nov 10, 2019 7:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.17
Replies: 2
Views: 48

Re: 2E.17

It depends on the shape of the molecule (i.e. trigonal planar, tetrahedral, etc.). You determine the shape based on the number of atoms and the number of lone pairs on the central atom.
by Jiyoon_Hwang_2I
Sun Oct 27, 2019 6:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: p-orbitals
Replies: 11
Views: 105

Re: p-orbitals

My TA said you don't have to write out the px, py, or pz so I think you can just combine them and write 1s^2 2s^2 2p^3
by Jiyoon_Hwang_2I
Sun Oct 27, 2019 6:02 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1B.25
Replies: 1
Views: 46

Re: 1B.25

For the first part of the question you would use the formula Δp ≥ h/4πΔx. Plug in Planck's constant for h and 350*10^-12 m for Δx. After plugging in all of the values you should get an answer close to 1.51*10^-25 kg*m*s^-1. Then, use the formula Δv = Δp/m (this formula is derived from the equation p...
by Jiyoon_Hwang_2I
Sun Oct 27, 2019 5:40 pm
Forum: DeBroglie Equation
Topic: 1.3
Replies: 2
Views: 66

Re: 1.3

I think you use the equation E = hc/λ. You would plug in Planck's constant, the speed of light, and the wavelength which would be 633 nm (633 * 10^-9 m). Then, you would get your answer in J/photon. Then, multiply this answer to (2.4 * 10^21 photons). Your answer would be in joules, but since they i...
by Jiyoon_Hwang_2I
Sun Oct 27, 2019 5:28 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 5
Views: 64

Re: Formal Charge

I think it's two shared electrons because in his example SO4 2-, for the oxygen, the equation was FC = 6 - (6 + 2/2) so the numerator in the fraction stands for the number of shared electrons and for SO4 2- the oxygen has a single bond with sulfur so the value of S was 2 since two electrons were sha...
by Jiyoon_Hwang_2I
Sun Oct 27, 2019 5:26 pm
Forum: Formal Charge and Oxidation Numbers
Topic: placement of the negative sign on charges
Replies: 4
Views: 67

Re: placement of the negative sign on charges

They're both correct. Both ways indicate a negative 2 charge.
by Jiyoon_Hwang_2I
Sun Oct 20, 2019 8:35 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Exceptions to Orbital Rules
Replies: 8
Views: 99

Re: Exceptions to Orbital Rules

The first exception was that a half full d^5 and full d^10 subshell have lower energy. So, for chromium the electron configuration would be [Ar] 3d^5 4s^1 and the electron configuration of copper would be [Ar] 3d^10 4s^1. The other exception was that the 4d state has lower energy than the 5s state, ...
by Jiyoon_Hwang_2I
Sun Oct 20, 2019 8:30 pm
Forum: *Black Body Radiation
Topic: Understanding Black Body Radiation
Replies: 4
Views: 133

Re: Understanding Black Body Radiation

Black body radiation is emitted by an object (the "black body") which absorbs all frequencies of light and emits radiation solely based on the wavelength rather than the composition of the object. However, I believe Dr. Lavelle said we don't need to know what black body radiation is.
by Jiyoon_Hwang_2I
Sun Oct 20, 2019 8:22 pm
Forum: Properties of Light
Topic: Wave Properties of Sound
Replies: 4
Views: 70

Re: Wave Properties of Sound

Yes, I think constructive and destructive wave properties would apply to sound. Constructive waves of sound would cause the sound to be louder and destructive waves would cause the sound to be quieter. This is because in constructive waves, the amplitude of the waves increase, whereas the amplitude ...
by Jiyoon_Hwang_2I
Sun Oct 20, 2019 8:16 pm
Forum: Properties of Light
Topic: Wien's Law
Replies: 2
Views: 50

Re: Wien's Law

I believe Wien's law is used to determine either the temperature or wavelength based on which variables are provided in the problem. However, I don't think we would need to know Wien's law as of now because on Outline 2 Dr. Lavelle did not put 1B.11 as an option which was the question about Wien's L...
by Jiyoon_Hwang_2I
Sun Oct 20, 2019 8:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E-11
Replies: 4
Views: 60

Re: 1E-11

The ground-state electron configuration for sodium would be 1s^2 2s^2 2p^6 3s^1. However, you can also use a shortcut by determining the closest noble gas to the given element (in this case neon is the closest noble gas to sodium) and then writing the electron configuration starting at this noble ga...
by Jiyoon_Hwang_2I
Sat Oct 12, 2019 6:19 pm
Forum: Properties of Light
Topic: Balmer vs Lyman series
Replies: 4
Views: 85

Re: Balmer vs Lyman series

I don't think it would be related to wavelength because the wavelengths of visible light all differ depending on what color light it is. So, the problem groups the series based on their absorption level because all the lines in the Lyman Series will always transition to/from n=1 and all the lines in...
by Jiyoon_Hwang_2I
Sat Oct 12, 2019 6:13 pm
Forum: Properties of Light
Topic: HW 1.A #11
Replies: 4
Views: 71

Re: HW 1.A #11

This question is basically saying that all the lines in the Lyman Series end at n=1 and all the lines in the Balmer Series ends at n=2. So, UV lines which are part of the Lyman Series will always transition to/from the energy level n=1 and visible light which is part of the Balmer Series will transi...
by Jiyoon_Hwang_2I
Fri Oct 11, 2019 12:14 pm
Forum: *Black Body Radiation
Topic: Self-test 1B.1B
Replies: 2
Views: 60

Re: Self-test 1B.1B

Use the equation T=constant/λ, where the constant is given as 2.9 mm*K (2.9*10^-3 m*K) and λ is 700 nm (700*10^-9 m).
If you plug these numbers into the equation you would get T=(2.9*10^-3 m*K)/(700*10^-9 m)=4.1*10^3 K
by Jiyoon_Hwang_2I
Fri Oct 11, 2019 12:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Question 1B.9
Replies: 2
Views: 71

Re: Homework Question 1B.9

First, I would do 32W * 2.0s to find the amount of energy, in Joules, that is emitted in 2.0s as stated in the first question. Then, use the equation E=hc/λ to determine the energy per photon. For h use Planck's constant (6.626*10^-34 Js), c use the speed of light (2.99792*10^8 m/s), and λ use wavel...
by Jiyoon_Hwang_2I
Fri Oct 11, 2019 11:48 am
Forum: Properties of Electrons
Topic: Energy Level Relationship
Replies: 4
Views: 59

Re: Energy Level Relationship

He said that as the energy level increased, E (the energy) decreases. Basically as n approaches infinite, E approaches zero. This is because n increasing means the electrons are moving further away from the nucleus, so the interaction between the electrons and the nucleus, E, decreases and approache...
by Jiyoon_Hwang_2I
Wed Oct 02, 2019 9:51 pm
Forum: Balancing Chemical Reactions
Topic: State Symbols in Equations
Replies: 8
Views: 128

Re: State Symbols in Equations

I would recommend writing the state of the molecules when writing the equation and usually the problems provide you with the state. For example, they'll say "in an aqueous solution of..." However, if the question doesn't tell you what state the molecules are at I don't think you will be pe...
by Jiyoon_Hwang_2I
Wed Oct 02, 2019 9:41 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 292

Re: Sig figs

You should always round your final answer to the correct number of sig figs. If you're doing addition/subtraction, round your answer to the least number of sig figs from any of the numbers in the given problem. If you're doing multiplication/division, round your answer to the least number of decimal...
by Jiyoon_Hwang_2I
Wed Oct 02, 2019 9:30 pm
Forum: Balancing Chemical Reactions
Topic: Stoichiometric Coefficients [ENDORSED]
Replies: 8
Views: 173

Re: Stoichiometric Coefficients [ENDORSED]

You may think that there are multiple correct answers for stoichiometric coefficients, but usually the stoichiometric coefficients should all be simplified to their lowest possible values. So, if you think there are multiple correct answers try dividing each coefficient by one number and if all the ...
by Jiyoon_Hwang_2I
Wed Oct 02, 2019 9:19 pm
Forum: SI Units, Unit Conversions
Topic: Next Week's Test
Replies: 8
Views: 161

Re: Next Week's Test

Yes, the test is only on the high school review unit that we learned until today. Although we started the quantum unit and will continue until we take the tests in our discussion sections, he said it won't be covered on next week's test.

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