Search found 102 matches

by Nathan Nakaguchi 1G
Wed Mar 11, 2020 1:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 275
Views: 108618

Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle, Prior to attending UCLA I had very little chemistry experience and was afraid of what I had signed up for. I am very grateful I have had the opportunity to learn from you for the past 2 quarters and be well introduced to one of my now favorite branches of science. I really apprecia...
by Nathan Nakaguchi 1G
Wed Mar 11, 2020 12:41 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration
Replies: 9
Views: 26

Re: Concentration

E=E^0-\frac{RT}{nf}ln([P]/[R]) E and T were given and R is a constant (8.314 J/Kmol). E^0= 0 since this is a concentration cell. The question also provided that the cathode reaction had some concentration which for concentration cells is the [R] in Q. Considering that the redox reaction was...
by Nathan Nakaguchi 1G
Wed Mar 11, 2020 12:33 pm
Forum: Second Order Reactions
Topic: linear graph
Replies: 7
Views: 35

Re: linear graph

A linear plot is in the form y=mx+b and for second order 1/[A] = kt + 1/[A]0 so the plot is 1/[A] versus time.
by Nathan Nakaguchi 1G
Wed Mar 11, 2020 12:21 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts vs. Intermediates
Replies: 8
Views: 25

Re: Catalysts vs. Intermediates

A catalyst is something that lowers the activation energy of a reaction and leaves K(equilibrium) the same, a catalyst should appear on both sides of the total net reaction, while an intermediate is an actual product between steps of the reaction that will not appear in the final net reaction.
by Nathan Nakaguchi 1G
Wed Mar 11, 2020 12:17 pm
Forum: Balancing Redox Reactions
Topic: Balancing basic reactions
Replies: 8
Views: 32

Re: Balancing basic reactions

For balancing basic reactions, add H2O's to balance oxygens, after that add H+'s to balance the hydrogens and finally, since this is basic, for every H+ you have added add that same amount of OH- onto both sides and note that OH-+H+=H2O, so there will be some cancelling.
by Nathan Nakaguchi 1G
Wed Mar 11, 2020 12:15 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Work and Delta G
Replies: 4
Views: 19

Re: Work and Delta G

G=Wmax always, but I think that Wmax=-nfE is only for standard conditions since that equation is from G^0=-nFE^0 which the knots imply standard conditions.
by Nathan Nakaguchi 1G
Fri Mar 06, 2020 3:15 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Units G=-nFE
Replies: 6
Views: 58

Re: Units G=-nFE

Volts = Joules/Coulomb so in deltaG=-nFE the Coulombs cancel out from the multiplication between E (J/C) and F (C/mol), and n has no units so the final units will be J/mol.
by Nathan Nakaguchi 1G
Fri Mar 06, 2020 3:12 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating ln Q
Replies: 20
Views: 162

Re: Calculating ln Q

Q is the reaction quotient, [Products]/[Reactants] for concentration cells the lower concentration is the products. Or the cathode concentration is the reactants and the anode concentration is the products.
by Nathan Nakaguchi 1G
Fri Mar 06, 2020 3:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert electrode
Replies: 9
Views: 52

Re: Inert electrode

You add an inert electrode like Pt(s) when the reaction does not have a conducting solid already involved.
by Nathan Nakaguchi 1G
Fri Mar 06, 2020 3:04 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Forward and reverse reaction rates
Replies: 4
Views: 30

Re: Forward and reverse reaction rates

k and k' have different numerical values, it is not necessarily a derivative or anything like that. Its the same as just arbitrarily writing k(forward) and k(reverse) they are both rate constants but they aren't the same number.
by Nathan Nakaguchi 1G
Wed Mar 04, 2020 3:14 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6.65
Replies: 3
Views: 46

Re: 6.65

The equation to use is E^0=(RT/nF)lnK and not E since pH's are always recorded at equilibrium, but that's about all I know. I'm also really unsure why K=[H+]/[OH-] either... the only reaction I can think of relating the two is H + OH -> 2H2O but that doesn't work here.
by Nathan Nakaguchi 1G
Thu Feb 27, 2020 4:41 pm
Forum: General Science Questions
Topic: Test 2
Replies: 16
Views: 119

Re: Test 2

Lavelle said in an email that the test will include the 2nd page of outline 4 and all of outline 5 (which can be found on his website)
by Nathan Nakaguchi 1G
Thu Feb 27, 2020 4:36 pm
Forum: Balancing Redox Reactions
Topic: OH- in Basic Solutions
Replies: 6
Views: 32

Re: OH- in Basic Solutions

You add xOH-'s to both sides after adding xH+'s. Notice that OH-+H+= H2O so that will likely lead to some cancelling. The general steps for balancing a redox reaction in a basic solution is 1.balance everything EXCLUDING H&O 2. balance O's by adding H2O 3. balance H's by adding H+ 4. add as many...
by Nathan Nakaguchi 1G
Thu Feb 27, 2020 4:30 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N3A
Replies: 4
Views: 70

Re: 6N3A

n is the moles of electrons within the redox reaction, so for this question n=2 since your reduction reaction and oxidation reaction both have 2e-. Concerning the separate Nernst equations either is fine to use, however the -.05916V one always assumes temperature is 298k (this one might also be more...
by Nathan Nakaguchi 1G
Thu Feb 27, 2020 4:21 pm
Forum: Balancing Redox Reactions
Topic: 6k3d
Replies: 3
Views: 24

Re: 6k3d

I ran into this too, I believe your right, it is supposed to be Cl- instead of Cl2 on the products side.
by Nathan Nakaguchi 1G
Thu Feb 27, 2020 4:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HW 6O.1
Replies: 1
Views: 32

Re: HW 6O.1

Compare the reduction potentials (E^0) of Ni2+ + 2e- to the H2O reduction reaction provided at the top of the 6O exercises. The cathode will be determined by which of the two has the greatest reduction potential, the one with the greater reduction potential will be the cathode and the one with the l...
by Nathan Nakaguchi 1G
Fri Feb 21, 2020 2:21 pm
Forum: Balancing Redox Reactions
Topic: balancing half reactions in a basic solution
Replies: 7
Views: 44

Re: balancing half reactions in a basic solution

Yes, add OH- to both sides and when you do also notice that OH- + H+ = H2O.
by Nathan Nakaguchi 1G
Fri Feb 21, 2020 2:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrode
Replies: 4
Views: 28

Re: Electrode

Platinum is not very reactive, so it is just a means of getting electrons from one source to the next for the actual electron transfer to occur.
by Nathan Nakaguchi 1G
Fri Feb 21, 2020 2:15 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Finding Gibbs free energy with K
Replies: 3
Views: 33

Re: Finding Gibbs free energy with K

R is a constant, so refer to the constants and equations sheet on Lavelle's website and choose whichever has the correct units you need. T is provided in the question.
by Nathan Nakaguchi 1G
Fri Feb 21, 2020 2:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E v E(standard)
Replies: 4
Views: 23

Re: E v E(standard)

E is the electromotive force of the system at any condition where is the electromotive force of a system at standard conditions 1M, 1atm, 273K.
by Nathan Nakaguchi 1G
Fri Feb 21, 2020 2:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5J.15
Replies: 3
Views: 51

Re: 5J.15

You have to use the H's and S's instead of G's because you have to calculate G for temperatures different than 25C. So you have to use where T= the different temperature.
by Nathan Nakaguchi 1G
Thu Feb 13, 2020 10:36 am
Forum: Student Social/Study Group
Topic: Midterm
Replies: 8
Views: 311

Re: Midterm

Off the top of my head I think something like 4I.9 and 4.43 were homework questions very similar to two on the midterm.
by Nathan Nakaguchi 1G
Thu Feb 13, 2020 10:34 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isobaric systems
Replies: 16
Views: 109

Re: Isobaric systems

When a system is isobaric that means that the pressure is constant, which implies that . I think this is all you can assume from this statement. Dr. Lavelle didn't really talk specifically about the terms isobaric and isochoric, so I wouldn't worry too much about it.
by Nathan Nakaguchi 1G
Thu Feb 13, 2020 10:29 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Why are exothermic reactions generally spontaneous?
Replies: 16
Views: 128

Re: Why are exothermic reactions generally spontaneous?

\Delta G=\Delta H - T\Delta S If delta G is negative then the reaction is spontaneous. So, using the formula above you can see that in most cases when \Delta H is negative and T\Delta S is positive or T\Delta S< \Delta H then delta G will be a negative value. There are generally more scenarios of d...
by Nathan Nakaguchi 1G
Thu Feb 13, 2020 10:21 am
Forum: Ideal Gases
Topic: STP
Replies: 7
Views: 71

Re: STP

STP is 0 Celsius, 273.15K and 1.00 atm. The equations should work the same except for when your dealing with things like \Delta G_{formation}^{0} where typically those constants are calculated from 298 K. Its probably best to make sure the constants you're dealing with explicitly say it was calculat...
by Nathan Nakaguchi 1G
Thu Feb 13, 2020 10:15 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: S vs Stotal
Replies: 7
Views: 74

Re: S vs Stotal



Usually if its just then it is the change in entropy of the system, the total change in entropy refers to both the change in entropy by the system and the surroundings.
by Nathan Nakaguchi 1G
Fri Feb 07, 2020 3:50 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Change in internal energy
Replies: 3
Views: 16

Re: Change in internal energy

\Delta U = 0 when it is isothermal, meaning temperature does not change so there is no net addition or loss of energy to the system. \Delta U = q + w, but since w can be written as w = - P_{ext}\Delta V in the cases where \Delta V = 0 (the volume is constant) then \Delta U = q + 0, thus \Delta U = ...
by Nathan Nakaguchi 1G
Fri Feb 07, 2020 3:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ∆S for summation
Replies: 3
Views: 34

Re: ∆S for summation

I'm not very sure, but my guess is that since its standard Gibbs free energy the only thing you need to do to calculate it is to do a Hess's approach only involving standard G's of formation.
by Nathan Nakaguchi 1G
Thu Feb 06, 2020 12:27 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 4F.17
Replies: 1
Views: 29

Re: 4F.17

Recall that S= Cln(T2/T1) so that's where heat capacities comes into play. Additionally since S= q/T then S= deltaHvap/T Those will be the formulas you will use for this question. Also, I think you have misread the question, you're reading 4F.18, 4F.17 uses water (however they both are the same proc...
by Nathan Nakaguchi 1G
Thu Feb 06, 2020 12:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Isothermal Process Slow Expansion
Replies: 2
Views: 12

Re: Isothermal Process Slow Expansion

For an isothermal process there is no addition or loss of energy, so the change in internal energy is 0. Since delta U = q +w and the definition of isothermal is no addition or loss of energy from the surroundings 0 = q + w. Doing some algebra can yield q = -w (remember that usually work= -number, a...
by Nathan Nakaguchi 1G
Wed Feb 05, 2020 9:27 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Change in entropy for a monatomic ideal gas vs diatomic molecules
Replies: 3
Views: 51

Change in entropy for a monatomic ideal gas vs diatomic molecules

If you were to compare the change in entropy of 1 mole of a monatomic ideal gas to 1 mole of atoms making up diatomic molecules by increasing both their temperatures, why would the 1 mole of monatomic ideal gas have a greater change in entropy? Problem 4H.9 in the book says something like this as an...
by Nathan Nakaguchi 1G
Wed Jan 29, 2020 10:48 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature
Replies: 6
Views: 54

Re: Temperature

Say A->B is exothermic, meaning that B is a lower energy state than A. B is therefore more stable to have, since it is lower energy meaning that the reaction will spontaneously go towards B (until it reaches equilibria) The less stable A requires more energy to be maintained. So if you add more heat...
by Nathan Nakaguchi 1G
Wed Jan 29, 2020 10:41 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimetry
Replies: 2
Views: 14

Re: Bomb Calorimetry

Bomb Calorimetry is the measure the amount of heat given off by a combustion reaction with constant volume.
by Nathan Nakaguchi 1G
Wed Jan 29, 2020 10:39 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: approximation
Replies: 4
Views: 37

Re: approximation

When the K is less than 10^-3 you can assume that something like (.15-x) in the denominator will become just .15 since the x is so small it does practically nothing to that amount. But in the numerator you will still have an x present like x^2.
by Nathan Nakaguchi 1G
Tue Jan 28, 2020 4:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: qp vs qv
Replies: 6
Views: 31

Re: qp vs qv

I think that the only difference between using the two is their corresponding heat capacities (in q=mCdeltaT). So for qp you'd use Cp and for qv you'd use Cv in your calculations.
by Nathan Nakaguchi 1G
Tue Jan 28, 2020 4:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: delta H units
Replies: 4
Views: 22

Re: delta H units

For the most part delta H will be in kJ/mol, as it represents energy absorbed or released per mole. I think that the only time it would not include "/mol" is probably when units in an analysis cause moles to cancel out. To be safe, I would stick with kJ/mol as it is what I've seen for majo...
by Nathan Nakaguchi 1G
Thu Jan 23, 2020 11:34 am
Forum: Phase Changes & Related Calculations
Topic: Adding and subtracting properties
Replies: 6
Views: 34

Re: Adding and subtracting properties

State properties only depend on the final and initial states. They only care about the destinations not the journey. So for deltas like enthalpy (which is state dependent), to find it you do: Final state value - Initial state value. State dependent properties are only involved with total changes fro...
by Nathan Nakaguchi 1G
Thu Jan 23, 2020 11:29 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le chatelier and Temperature
Replies: 9
Views: 64

Re: Le chatelier and Temperature

For Delta H= +, then the reaction is endothermic meaning it needs input For Delta H= -, then the reaction is exothermic and is spontaneous/needs no input. The way I like to think about these is that for endothermic reactions, they are going from generally a more stable form to a less stable form thu...
by Nathan Nakaguchi 1G
Tue Jan 21, 2020 4:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: H2O in K Expressions
Replies: 6
Views: 31

Re: H2O in K Expressions

Only liquids and solids are supposed to be ignored in K expressions. While it is H2O we're talking about (which tends to be liquid and therefore ignored), if it is in the gas phase it should be used in the expression.
by Nathan Nakaguchi 1G
Tue Jan 21, 2020 4:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.15
Replies: 1
Views: 35

Re: 6D.15

This one is a little tricky, you have to recall that Al^3+ is a central metal ion in chelation. So for AlCl3(aq)+H2O(l) the Cl3- ion and Al^3+ will depart and Cl3- doesn't affect the pH so it can be ignored. With the Al^3+ in water 6 H2O molecules will bond to make an octahedral Al(H2O)^3+. So the r...
by Nathan Nakaguchi 1G
Tue Jan 21, 2020 4:05 pm
Forum: Ideal Gases
Topic: pressure
Replies: 10
Views: 69

Re: pressure

Partial pressure just means that it is a part/contributing to the total pressure of the system. Total pressure is all of the components of a reaction that would cause pressure combined (added), while partial pressure is just the pressure created by one aspect or compound.
by Nathan Nakaguchi 1G
Wed Jan 15, 2020 10:11 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Real reason explaining Le Chatelier's principle
Replies: 4
Views: 33

Re: Real reason explaining Le Chatelier's principle

Le Chatelier's Principle says that a reaction will counteract a change in order to stay at equilibrium. If you increase pressure, P=(nRT)/V then you are essentially altering n/v (either making v smaller or n larger) also known as the concentration, and if the concentration of everything in the react...
by Nathan Nakaguchi 1G
Wed Jan 15, 2020 10:01 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q=K
Replies: 14
Views: 70

Re: Q=K

Q can be calculated at any time (including when it has already reached equilibrium) during the reaction and is compared to K to see the direction of the reaction, if Q equals K then that just means the reaction is at equilibrium.
by Nathan Nakaguchi 1G
Wed Jan 15, 2020 9:58 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I.11 units
Replies: 5
Views: 47

Re: 5I.11 units

From my ebook it says 1.20 milli-mol SO2, I think you may have misread it or there was a typo.
by Nathan Nakaguchi 1G
Wed Jan 15, 2020 9:55 am
Forum: Ideal Gases
Topic: Partial Pressure
Replies: 8
Views: 55

Re: Partial Pressure

It is partial pressure because each compound contributes to the whole pressure, so the pressure caused by one compound would be called partial.
by Nathan Nakaguchi 1G
Tue Jan 14, 2020 2:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.3
Replies: 1
Views: 40

Re: 6D.3

I think its cause .10M is the initial value of HClO2, I think the way that Ka and Kb work is similar to regular K in that the system must be at equilibrium. So while there was .10M of HClO2 at the start, .06 of it became the product(s) thus the final HClO2 you would put into the calculations would b...
by Nathan Nakaguchi 1G
Thu Jan 09, 2020 3:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to assume x=0 for ICE box problems
Replies: 1
Views: 23

When to assume x=0 for ICE box problems

In question 5i.29 of the textbook, the solution has you omit x in the denominator (or treat it as 0) since the provided K is 3.2x10^-34. For what range of K's are you allowed to say is small enough to treat x as a 0? And what is the justification for treating the denominator's x like this?
by Nathan Nakaguchi 1G
Wed Jan 08, 2020 5:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to find stability based off of equilibrium concentrations
Replies: 2
Views: 33

How to find stability based off of equilibrium concentrations

Problem 5i13 part c for reference, asks to determine which dissociation reaction is more thermodynamically stable, dichloride to chlorine vs difluorine to fluorine. I know that a reaction reaches its equilibrium constant so that its ratio of products to reactant is as stable as possible, but how can...
by Nathan Nakaguchi 1G
Tue Jan 07, 2020 3:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: How to interpret reactions based on quotient in relation to equilibrium constant
Replies: 5
Views: 48

How to interpret reactions based on quotient in relation to equilibrium constant

How can you tell if more products or more reactants will be formed in a reaction based on the Q compared to K? Is there a rule? Like if Q<K it makes products?
by Nathan Nakaguchi 1G
Tue Jan 07, 2020 11:14 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Heterogenous vs. Homogenous equations
Replies: 6
Views: 42

Re: Heterogenous vs. Homogenous equations

Heterogenous equations contain compounds with different (hetero) phases while homogenous equations contain the same (homo) phases. For example a chemical equation with all of the compounds in the gas phase is homogenous.
by Nathan Nakaguchi 1G
Tue Jan 07, 2020 11:12 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Hw Problem G2
Replies: 5
Views: 61

Re: Hw Problem G2

I believe it is true, the reaction will reach equilibrium ending with satisfying the ratio of products to reactants (and/or reactants to products ratio) that makes up the equilibrium constants k and k^-1.
by Nathan Nakaguchi 1G
Fri Dec 06, 2019 5:02 pm
Forum: Electronegativity
Topic: Electronegativity of Atoms We Should Know About
Replies: 3
Views: 67

Re: Electronegativity of Atoms We Should Know About

It is probably best to memorize the periodic trends that electronegativity has. As you go up the table EN increases, and as you go right from the table EN increases. I don't believe we will have to know the exact hierarchy/numbers for electronegativity, we just need to be able to work with the idea ...
by Nathan Nakaguchi 1G
Fri Dec 06, 2019 4:50 pm
Forum: Conjugate Acids & Bases
Topic: oxoacids
Replies: 3
Views: 61

Re: oxoacids

Oxoacids are a category of acids that contain oxygen(s) which hold/bond to the soon-to-be-donated hydrogen/proton. HClO3 falls into the oxoacids category.
by Nathan Nakaguchi 1G
Fri Dec 06, 2019 4:46 pm
Forum: Hybridization
Topic: 2F.15
Replies: 1
Views: 21

Re: 2F.15

S character of a bond refers to how much S is relatively in the hybridization, so for example sp3 has less S character than sp2 which will have less S character than sp (ie sp will have the most S character). Notice the corresponding molecular shapes that one can make with the central atom being sp3...
by Nathan Nakaguchi 1G
Fri Dec 06, 2019 11:25 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Identifying electron donors vs electron withdrawers (6C 21)
Replies: 1
Views: 44

Identifying electron donors vs electron withdrawers (6C 21)

I understand that electron withdrawers would make a molecule more likely to lose a proton and electron donors less likely to lose a proton. Like in 6C 21 how acetic acid is a weaker acid than formic acid since the methyl group -CH3 on the acetic acid is a electron donor to the molecule making it sli...
by Nathan Nakaguchi 1G
Fri Dec 06, 2019 11:09 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Determining relative strengths of bases (6C 17)
Replies: 1
Views: 32

Determining relative strengths of bases (6C 17)

How does one determine which base is stronger than the other. For example, in 6C 17 we are given BrO- and C17H19O3N (morphine). My answer would be that BrO- is more basic because it has a full negative charge to pull in protons compared to morphine's possible lone pairs (I haven't attempted to creat...
by Nathan Nakaguchi 1G
Sun Dec 01, 2019 2:41 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: What is kA value?
Replies: 5
Views: 34

Re: What is kA value?

kA is the ionization constant which lets you know how ionized/dissociated a solution is. The more ionized the stronger it is, the less ionized the weaker.
by Nathan Nakaguchi 1G
Sun Dec 01, 2019 2:32 pm
Forum: Sigma & Pi Bonds
Topic: Ionic bond --> sigma and pi bonds
Replies: 8
Views: 100

Re: Ionic bond --> sigma and pi bonds

Sigma and Pi bonds are overlapping of orbitals/ sharing electrons. Ionic bonds do not share electrons, so they do not include sigma or pi bonds.
by Nathan Nakaguchi 1G
Sun Dec 01, 2019 2:29 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids
Replies: 3
Views: 30

Re: Lewis Acids

I remember it as a base will take electrons while an acid will receive electrons (I use bronsted definition).
by Nathan Nakaguchi 1G
Sun Dec 01, 2019 2:27 pm
Forum: Naming
Topic: Names of ligands
Replies: 4
Views: 38

Re: Names of ligands

I believe it is primarily the naming rules for coordinate compounds, which involves memorization of ligands. Dr. Lavelle sent a email with a pdf for the naming rules and etc around 2 weeks ago. I would go off of that.
by Nathan Nakaguchi 1G
Tue Nov 26, 2019 3:50 pm
Forum: Student Social/Study Group
Topic: -ate Nomenclature for final?
Replies: 2
Views: 38

-ate Nomenclature for final?

I'm currently doing the Acids and Bases HW and a handful of questions require knowledge of ate/ite nomenclature which I don't think we have covered thus far. For the final will it be necessary that we fully know "-ate" nomenclature? Thanks.
by Nathan Nakaguchi 1G
Sat Nov 23, 2019 11:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shaped v. Trigonal pyramid
Replies: 9
Views: 77

Re: T-shaped v. Trigonal pyramid

A= central atom, X= bonded atoms, E= lone pairs.

T shape: AX3E2

trigonal pyramid: AX3E
by Nathan Nakaguchi 1G
Sat Nov 23, 2019 11:31 pm
Forum: Biological Examples
Topic: Biological Importance
Replies: 6
Views: 36

Re: Biological Importance

I'm not sure specifically. I believe the fact that pH impacts function in biological systems is probably the biggest takeaway. I'll just list what other parts i remember that where mentioned: Copper, Zinc, and Nickel contribute to enzyme function (which speed up reactions), Iron is important in elec...
by Nathan Nakaguchi 1G
Sat Nov 23, 2019 11:20 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 15
Views: 120

Re: Cisplatin

I believe cisplatin bonds to two nucleotides preventing the DNA to unravel itself and therefore can't be replicated.
by Nathan Nakaguchi 1G
Sat Nov 23, 2019 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and its relation to Hybridization
Replies: 3
Views: 28

Re: VSEPR and its relation to Hybridization

I think that the amount of electron densities a molecule has corresponds to the kind of hybridization shells may be present so VSEPR may be helpful in that if you know its shape you know the amount of electron densities. .
by Nathan Nakaguchi 1G
Sat Nov 23, 2019 11:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: ligand
Replies: 3
Views: 28

Re: ligand

A ligand is a ion or molecule that creates a coordinate bond to a metal atom.
by Nathan Nakaguchi 1G
Fri Nov 15, 2019 10:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Notation
Replies: 5
Views: 43

Re: VSEPR Notation

Usually A will not be accompanied by a number as it represents the central atom of the molecule. Whatever number follows X represents how many atoms are bonded to the central atom A. The number that comes with E represents how many lone pairs there are on the molecule's central atom.
by Nathan Nakaguchi 1G
Fri Nov 15, 2019 10:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: regions of electron density
Replies: 7
Views: 49

Re: regions of electron density

I think of regions of electron density just as another way to say a general area of a group of electrons, so on a molecule wherever either lone pairs or bonds are is a general area of a group electrons therefore regions of electron density.
by Nathan Nakaguchi 1G
Fri Nov 15, 2019 10:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 130

Re: Bent or Angular

Personally I refer to it as angular for the same reasons as the post before me. I think either is acceptable, but double check with your TA to be sure.
by Nathan Nakaguchi 1G
Fri Nov 15, 2019 10:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: test 2
Replies: 13
Views: 100

Re: test 2

Unless on Monday Dr. Lavelle teaches hybridization, I don't think it will show up on test two. He said for test two it will be everything between the midterm up until Monday (which I believe he will teach sigma and pi bonds).
by Nathan Nakaguchi 1G
Fri Nov 15, 2019 9:58 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing power vs polarizability
Replies: 5
Views: 64

Re: Polarizing power vs polarizability

polarizing power is how powerful a specific ion can polarize another ion (pull/distort a electron cloud towards it)

polarizability is how much a ion can be polarized (how distorted it can become)
by Nathan Nakaguchi 1G
Thu Nov 07, 2019 2:04 pm
Forum: Administrative Questions and Class Announcements
Topic: What homework to turn in per week
Replies: 7
Views: 81

What homework to turn in per week

In general, what range of time should we use as a rule of thumb to determine what section of homework we should turn in for that week? I'm guessing 2 but I'm not sure if thats too long.
by Nathan Nakaguchi 1G
Thu Nov 07, 2019 11:50 am
Forum: Ionic & Covalent Bonds
Topic: Mini Dino Nuggets 2b
Replies: 6
Views: 67

Re: Mini Dino Nuggets 2b

As you go up and right electronegativity increases. Using this rule Florine is more electronegative than Bromine so the differences are EN(F) - EN(C) versus EN(Br) - EN(C) since you know Florine's EN will be larger the difference between F and C is greater than C and Br. The more significant the ele...
by Nathan Nakaguchi 1G
Thu Nov 07, 2019 11:36 am
Forum: Ionic & Covalent Bonds
Topic: Correcting Ionic Model
Replies: 4
Views: 63

Re: Correcting Ionic Model

Yes you are correct in both aspects. The way I think of it is a covalent bond is a sharing of electrons and ionic bond is an anion stealing an electron from a cation. Some ionic bonds show covalent character because as an ionic bond is polarized some electrons (or the electron cloud) "stretch&q...
by Nathan Nakaguchi 1G
Thu Nov 07, 2019 11:29 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency
Replies: 6
Views: 72

Re: Bohr Frequency

When energy is absorbed the system is gaining energy so that is a positive delta E going from a lower n to a higher n.
by Nathan Nakaguchi 1G
Tue Nov 05, 2019 3:54 pm
Forum: Administrative Questions and Class Announcements
Topic: For the midterm will we need to know how to do electron configurations for the f shell? [ENDORSED]
Replies: 2
Views: 602

For the midterm will we need to know how to do electron configurations for the f shell? [ENDORSED]

For the midterm will we need to know how to do electron configurations for the f shell?

Also, do we have to memorize what general ranges the different types of electromagnetic radiation are in?
by Nathan Nakaguchi 1G
Fri Nov 01, 2019 5:00 pm
Forum: Bond Lengths & Energies
Topic: dissociation energy
Replies: 7
Views: 62

Re: dissociation energy

I'm not 100% on this but I believe Dissociation energy is always positive because breaking a bond will always require an input of energy, if it were to release energy dissociation energy would be negative but that can't happen because breaking a bond is going from a lower potential energy to a highe...
by Nathan Nakaguchi 1G
Fri Nov 01, 2019 11:30 am
Forum: Ionic & Covalent Bonds
Topic: How does one find a most likely charge for ions for a given element?
Replies: 6
Views: 61

How does one find a most likely charge for ions for a given element?

Currently working on Homework 2A #15, essentially it asks to find a most likely charge for a given element if it were to become an ion (like for S or Ga). I'm not sure how to approach this, do I focus on ionization energy and electron affinity? How does one determine how many electrons gained or los...
by Nathan Nakaguchi 1G
Thu Oct 31, 2019 10:22 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 7
Views: 67

Re: Midterm

If you go onto Dr. Lavelle's website under the class websites tab, scroll down slightly, on the right you should see a section with the title "Exam information." Click "midterm review sessions and rooms" and it should bring you to a pdf with all the info you need about the midter...
by Nathan Nakaguchi 1G
Thu Oct 31, 2019 10:18 am
Forum: Einstein Equation
Topic: Joules units
Replies: 6
Views: 144

Re: Joules units

Planck's Constant's units are J * s (joules times seconds) not necessarily just joules, thats why the Planck's units are (kg m^2 s^-2) * (s) = kg m^2 s^-1.
by Nathan Nakaguchi 1G
Thu Oct 31, 2019 10:14 am
Forum: Properties of Electrons
Topic: Formal Charge of an Atom
Replies: 5
Views: 79

Re: Formal Charge of an Atom

Formal Charge is assigned to an atom by following the formula: FC= V - (L+S/2) where V is the amount of valence electrons the atom has, L are the lone pairs it has (on a Lewis structure it would be the pairs of dots like ":"), and s being the bonds the atom has.
by Nathan Nakaguchi 1G
Fri Oct 25, 2019 11:10 am
Forum: Formal Charge and Oxidation Numbers
Topic: charges and roman numerals
Replies: 5
Views: 437

Re: charges and roman numerals

Roman numerals next to atoms/metals just indicate the specific charge it has since metals can have a variety of different charges for the same thing. So this one the (III) indicates a +3 charge
by Nathan Nakaguchi 1G
Fri Oct 25, 2019 11:05 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Atomic Radius
Replies: 18
Views: 137

Re: Atomic Radius

The atomic radius is half the distance between the centers of neighboring atoms, I don't think we will have to ever calculate a measurement for this (it would probably be given). I believe to answer this question you go based off of the periodic trends of atomic radii, as you go down and left of the...
by Nathan Nakaguchi 1G
Thu Oct 24, 2019 11:20 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 13
Views: 200

Re: Electron Configurations

For me, I don't memorize the order I just have memorized the exceptions like when you get to Cr the D shell can have 10 electrons and Cu's 4s shell can only hold 1 electron. The main thing I try to do when finding electron configuration is to build up from the shells (counting the electrons) and to ...
by Nathan Nakaguchi 1G
Thu Oct 24, 2019 11:03 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty value in equation
Replies: 9
Views: 74

Re: Uncertainty value in equation

Uncertainty accounts for both the positive and negative, so if your v was 103 +or- 3 then the uncertainty would be 3(2)= 6.
by Nathan Nakaguchi 1G
Mon Oct 21, 2019 5:20 pm
Forum: SI Units, Unit Conversions
Topic: Unit conversion
Replies: 15
Views: 275

Re: Unit conversion

For conversions involving angstroms use the ratio: 10^-10m/Angstrom. For example 100pm*(10^-12m/pm)*(1Angstrom/10^-10m)= 100*10^-2 Angstroms.
by Nathan Nakaguchi 1G
Fri Oct 18, 2019 5:33 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 3d104s2
Replies: 1
Views: 19

Re: 3d104s2

I'm not entirely sure on this either, but here is my two cents: 3d orbitals are lower energy than 4s orbitals because the n=3 on the 3d and n=4 on the 4s and we know n refers to energy and the electron configuration is written out in increasing order (so 4s2,3d10 is not correct because the order of ...
by Nathan Nakaguchi 1G
Fri Oct 18, 2019 5:15 pm
Forum: DeBroglie Equation
Topic: Linear Momentum
Replies: 6
Views: 84

Re: Linear Momentum

Linear momentum is p, where its formula is composed of p=mv or Momentum = Mass (usually kg) * Velocity (usually m/s).
by Nathan Nakaguchi 1G
Thu Oct 17, 2019 4:22 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin State
Replies: 17
Views: 103

Re: Spin State

+1/2 refers to spin up and -1/2 refers to spin down. I believe it is a reference to what would happen if you performed an experiment similar to the one Dr. Lavelle showed in lecture Oct 16th (the silver atoms one). Some electrons end up going upwards after going through a magnetic field while some o...
by Nathan Nakaguchi 1G
Thu Oct 17, 2019 4:16 pm
Forum: DeBroglie Equation
Topic: Constant Question
Replies: 7
Views: 76

Re: Constant Question

Personally, I would use whatever number is more accurate. In test scenarios I would go for every digit given on the constants sheet. It shouldn't be too much of a big deal though to opt for 6.63 so long as it is clear that you're using that number and your answer is pretty much the same.
by Nathan Nakaguchi 1G
Thu Oct 17, 2019 4:12 pm
Forum: Photoelectric Effect
Topic: Unit of measurements for E=hv
Replies: 6
Views: 61

Re: Unit of measurements for E=hv

For E=hv, h has the unit J*s and v has hz or s^-1 so the answer should come out to be in just joules J (s*s^-1=1), however for this question the v calculated is per photon so it is ok to make it J per photon.
by Nathan Nakaguchi 1G
Thu Oct 10, 2019 3:55 pm
Forum: Properties of Light
Topic: Energy of light
Replies: 4
Views: 58

Re: Energy of light

Yes, it is always true that shorter wavelengths lead to higher energy because based off of c=wavelength *frequency if wavelength decreases the frequency has to increase to satisfy the equation and if frequency goes up energy goes up based off of the equation E= h * frequency.
by Nathan Nakaguchi 1G
Thu Oct 10, 2019 10:47 am
Forum: Administrative Questions and Class Announcements
Topic: Can't find my old posts
Replies: 1
Views: 40

Can't find my old posts

After I've commented (or I look at one of my comments) when I click on the box on the right with my name I see that it says I have posted 10 times, I click on it and it shows me my posts, but I can only find 9 of the 10. I remember commenting on a photoelectric effect post this week but I can't find...
by Nathan Nakaguchi 1G
Thu Oct 10, 2019 10:42 am
Forum: Properties of Light
Topic: Finding Wavelength and Energy of Photon
Replies: 1
Views: 39

Re: Finding Wavelength and Energy of Photon

To find the wavelength of Krypton-86 I would use the ratio that they gave you so: (1 meter/1,650,763.73 krypton wavelengths) * (1 Krypton wavelengths) to convert to krypton wavelength in meters (or nanometers). From there I would use the formula c= Wavelength * Frequency, solve for frequency, and pl...
by Nathan Nakaguchi 1G
Thu Oct 10, 2019 10:32 am
Forum: Properties of Light
Topic: 1A 3 Chemical Principle 7th edition
Replies: 2
Views: 22

Re: 1A 3 Chemical Principle 7th edition

Decreasing frequency of light leads to less energy per photon, (E=hv). So I think that the extent of the change in the electrical field at a given point decreases because the energy of the light (electromagnetic radiation) has decreased. Or another way is that the electric field vector's height have...
by Nathan Nakaguchi 1G
Tue Oct 08, 2019 4:45 pm
Forum: Empirical & Molecular Formulas
Topic: empirical to molecular formula [ENDORSED]
Replies: 9
Views: 156

Re: empirical to molecular formula [ENDORSED]

I believe it goes: (Molar Mass Given)/(Empirical molar mass)= Number you need to multiply the empirical formula to get the molecular formula.
by Nathan Nakaguchi 1G
Thu Oct 03, 2019 8:45 pm
Forum: SI Units, Unit Conversions
Topic: Scientific Notation (general requirement for the course)
Replies: 5
Views: 58

Re: Scientific Notation (general requirement for the course)

I'm not entirely sure, I think that you're only required to write the correct amount of sig figs, but there can be cases were scientific notation would be more practical. I would just make sure that the reader can understand the sig figs in your answer.
by Nathan Nakaguchi 1G
Wed Oct 02, 2019 6:08 pm
Forum: Balancing Chemical Reactions
Topic: H13 Is there a good step by step way to balance this?
Replies: 4
Views: 44

Re: H13 Is there a good step by step way to balance this?

So there is not really a step by step process for a reaction like this? Do you just kinda have to use your intuition to figure out problem like this one?
by Nathan Nakaguchi 1G
Wed Oct 02, 2019 5:55 pm
Forum: Balancing Chemical Reactions
Topic: H13 Is there a good step by step way to balance this?
Replies: 4
Views: 44

H13 Is there a good step by step way to balance this?

Usually I have no issues balancing reactions, but the second part of problem H13 broke my usual solving steps. I usually balance from least frequent to most frequent but when I try to do that on NO + O2 = NO2 it just confuses me. I go from least frequent to most, so I first balance the N's which is ...
by Nathan Nakaguchi 1G
Tue Oct 01, 2019 3:50 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Mole Units
Replies: 2
Views: 55

Re: Mole Units

Moles can be used for anything because it is like using the term dozen. If there are 12 eggs present you can say there are a dozen eggs, if there were 6 eggs you apply the the dozen ratio: (12 things = 1 Dozen things) and say there are .5 dozen eggs. In the chemistry world chemists like to use moles...

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