Search found 33 matches

by Julia Nakamura 2D
Sat Mar 18, 2017 1:59 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Why is this cis?
Replies: 7
Views: 1086

Re: Why is this cis?

How can you tell that the two highest priority molecules are on the same side?
by Julia Nakamura 2D
Thu Mar 16, 2017 8:07 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Practice Problems
Replies: 16
Views: 1976

Re: Practice Problems

For the last question on Problem Set 1, how do you know whether to draw the 3 substituents in the axial or equatorial positions? So why are 2/3 of them equatorial in one conformation and 2/3 of them are axial in another conformation?
by Julia Nakamura 2D
Mon Mar 13, 2017 3:31 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Primary, Secondary, Tertiary Naming
Replies: 1
Views: 534

Re: Primary, Secondary, Tertiary Naming

Yes, I believe that you only have to specify primary, secondary, or tertiary when asked what functional group is attached, just to be as specific as possible.
by Julia Nakamura 2D
Mon Mar 13, 2017 3:28 pm
Forum: *Alkenes
Topic: Naming an Alkene
Replies: 1
Views: 283

Re: Naming an Alkene

The "diene" is used to indicate that there are two double bonds, instead of one. The two double bonds are on the 1 and 3 carbon atoms, respectively. If there were three double bonds, you would put "triene", etc.
by Julia Nakamura 2D
Mon Mar 06, 2017 3:05 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Arrows
Replies: 4
Views: 434

Re: Arrows

Basically, the arrow needs to be drawn from the source of the electron (lone pairs, double bonds, or triple bonds) to where the electrons are going.
by Julia Nakamura 2D
Fri Mar 03, 2017 9:06 pm
Forum: *Nucleophilic Substitution
Topic: Electron flow arrows
Replies: 2
Views: 636

Re: Electron flow arrows

I don't know if it's mandatory to indicate the dipoles, but I don't think it would hurt. It may help you figure out how to draw the arrows and prevent you from making any mistakes.
by Julia Nakamura 2D
Mon Feb 27, 2017 8:14 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Naming Organic Molecules
Replies: 19
Views: 2117

Re: Naming Organic Molecules

A carbocation is molecule where the carbon atom only has three bonds, thus giving it a positive charge. They are usually unstable because they do not have eight electrons (they only have six), and therefore do not satisfy the octet rule.
by Julia Nakamura 2D
Mon Feb 27, 2017 8:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Intro to OChem Textbook?
Replies: 2
Views: 280

Re: Intro to OChem Textbook?

From what I can see so far with OChem, we won't be using the textbook in class, but it is needed for all of the reading and homework problems. If this changes, I'm guessing Dr. Lavelle will announce it in class.
by Julia Nakamura 2D
Mon Feb 20, 2017 8:22 pm
Forum: First Order Reactions
Topic: Rate 1st Order Rxn
Replies: 3
Views: 499

Re: Rate 1st Order Rxn

The rate law for a first order reaction is k[A]. However, the integrated rate law is ln[A]= -kt + ln[A]naught, which means that there is only one value for k in the integrated rate law. It looks like you may have just mixed up the equations.
by Julia Nakamura 2D
Wed Feb 15, 2017 9:01 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Formulas
Replies: 3
Views: 464

Re: Formulas

This equation comes from the ideal gas law, PV=nRT. This formula can also be translated to P(delta-V)=delta-nRT, which basically says that the pressure times the change in volume is equivalent to the change in moles times R and T.
by Julia Nakamura 2D
Mon Feb 13, 2017 2:23 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: electrodes
Replies: 1
Views: 233

Re: electrodes

What do we do when we are given a redox reaction and there is no solid metal conductor for one of the half reactions? How do electrons get transferred in that case? So when there is no solid metal conductor, you must assume there is an inert electrode, such as Pt(s), that is transferring the electro...
by Julia Nakamura 2D
Tue Feb 07, 2017 10:32 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: memory trick [ENDORSED]
Replies: 3
Views: 586

Re: memory trick [ENDORSED]

I actually noticed that too while looking over the course reader, and I think it's an awesome memory trick. Thanks for sharing that with everyone!
by Julia Nakamura 2D
Mon Feb 06, 2017 2:15 pm
Forum: Balancing Redox Reactions
Topic: Chapter 14 Question 3
Replies: 7
Views: 715

Re: Chapter 14 Question 3

Yes, so after finding which species are being oxidized and reduced, you can write two unbalanced equations for the half reactions. The next steps are to balance all of the elements, then balance the oxygens by using H2O, and then balance the hydrogens by using H+. There is a clearer outline of these...
by Julia Nakamura 2D
Mon Feb 06, 2017 2:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Number of mols to use in the equation [ENDORSED]
Replies: 3
Views: 460

Re: Number of mols to use in the equation [ENDORSED]

Yes, you would still need to identify the oxidation states in order to balance the equation properly. This would help you solve for the number of electrons on each side of the equation, which would help you find n.
by Julia Nakamura 2D
Mon Jan 30, 2017 2:50 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: entropy versus degenercy
Replies: 1
Views: 273

Re: entropy versus degenercy

Yes, your definitions are correct. Entropy is the likelihood or probability that a system will be in a particular state, also referred to as the disorder of the system. Degeneracy is the number of ways of achieving a given energy state. So for Entropy S, W will be the number of ways to achieve S.
by Julia Nakamura 2D
Mon Jan 23, 2017 3:59 pm
Forum: Phase Changes & Related Calculations
Topic: Question about 8.21
Replies: 1
Views: 245

Re: Question about 8.21

Because the copper has a higher temperature than the water, when you place the copper into the water, heat will be transferred from the copper to the water. You can assume that the amount of heat that is lost by the metal will then be the same amount of heat that is gained by the water (since it say...
by Julia Nakamura 2D
Mon Jan 16, 2017 6:55 pm
Forum: Phase Changes & Related Calculations
Topic: heating curve
Replies: 3
Views: 367

Re: heating curve

On the graph where there are horizontal lines, heat is being aded but the temperature remains constant. This is because the heat added is being used to break bonds to change their structure. (for example, in water, bonds between H20 molecules are being broken so that the particles can move past each...
by Julia Nakamura 2D
Mon Jan 16, 2017 6:48 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: HW Question 8.9
Replies: 5
Views: 556

Re: HW Question 8.9

Yes, the constants and formulas on page 125 of the course reader are all given on quizzes and exams.
by Julia Nakamura 2D
Wed Jan 11, 2017 4:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bonding Enthalpies
Replies: 2
Views: 299

Re: Bonding Enthalpies

Yes, the carbon-carbon double bond is broken completely, and we do not measure the double bond break as a single bond break. This also means that the single bond formed between the carbons is considered a brand new bond. So, the enthalpy of the double bond that was broken (between the two carbons) w...
by Julia Nakamura 2D
Mon Nov 28, 2016 11:32 am
Forum: Polyprotic Acids & Bases
Topic: Ka1 vs Ka2 vs Ka3
Replies: 2
Views: 1868

Re: Ka1 vs Ka2 vs Ka3

So as Ka increases in subscript, it becomes more difficult to remove H+ ions from the acid because the ion is becoming more negatively charged (which makes it not want to remove any more H+ ions). For example, H2CO3 will give off one H+ to become HCO3-. However, it is harder for HCO3- to lose anothe...
by Julia Nakamura 2D
Sun Nov 20, 2016 7:54 pm
Forum: Ideal Gases
Topic: Chemical Equilibrium
Replies: 1
Views: 232

Re: Chemical Equilibrium

I believe this was answered a few posts down in more detail, but K=1 is rare because it means that neither the reactants or products are being favored in the reaction, which is rare and doesn't happen very often. Dr. Lavelle also added that K=1 means that while the reactant and product have differen...
by Julia Nakamura 2D
Mon Nov 14, 2016 11:21 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Equilibrium Constant vs Reaction Quotient [ENDORSED]
Replies: 4
Views: 906

Re: Equilibrium Constant vs Reaction Quotient [ENDORSED]

Yes. So when calculating Q and K, either pressures (for gases) or concentrations in moles/L (molarity for aqueous solutions) are used. Q and K do not have units, but the values used to solve for Q and K will have units.
by Julia Nakamura 2D
Mon Nov 07, 2016 4:37 pm
Forum: Naming
Topic: Chapter 17 #31 a & c
Replies: 1
Views: 289

Re: Chapter 17 #31 a & c

So the charge of a potassium atom is +1, and the charge of [Cr(CN)6] is -3 (because the CN's each have a -1 for a total of -6 and the Cr is +3). In order to make this coordination compound neutral, we need three potassium atoms to balance out the -3 charge of the [Cr(CN)6]. The same applies to there...
by Julia Nakamura 2D
Mon Oct 31, 2016 8:21 pm
Forum: Empirical & Molecular Formulas
Topic: Mistake in the 2009 Midterm Solutions?
Replies: 2
Views: 447

Re: Mistake in the 2009 Midterm Solutions?

Adding onto the the comment above, whenever you are finding empirical/molecular formulas, you must first convert the elements to moles before dividing by the one that has the smallest number of moles. You can make sure to do this by seeing if the units cancel when you multiply the grams by grams/mole.
by Julia Nakamura 2D
Mon Oct 24, 2016 9:03 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Isoelectronic, Electron Affinity and Ionic Bonds
Replies: 1
Views: 648

Re: Isoelectronic, Electron Affinity and Ionic Bonds

Elements that are isoelectronic contain the same number of electrons. For example, F- and Ne are isoelectronic, containing the same number of electrons, but still having very different properties. Electron affinity is the energy released when an electron is added to a gas-phase atom. Electron affini...
by Julia Nakamura 2D
Mon Oct 17, 2016 9:42 am
Forum: Lewis Structures
Topic: Electron Configuration CH3 Problem 11
Replies: 1
Views: 324

Re: Electron Configuration CH3 Problem 11

So [Ar]3d5 would be Fe3+ because in order to get the positive charge of 3+, you would need to remove three electrons from Fe. The ground state configuration for Fe is 3d^6 4s^2. So, we would take two electrons from the outermost state (both of the 4s electrons) and then one electron from the 3d stat...
by Julia Nakamura 2D
Mon Oct 10, 2016 6:48 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Shell numbers (n) for d-block elements
Replies: 2
Views: 261

Re: Shell numbers (n) for d-block elements

Thank you, that makes much more sense. So K would have n=4 since it is in the 4s state, but Sc would have n=3 since it is in the 3d state.
by Julia Nakamura 2D
Mon Oct 10, 2016 3:39 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Shell numbers (n) for d-block elements
Replies: 2
Views: 261

Shell numbers (n) for d-block elements

On the periodic table, I know that period one corresponds to n=1 and period two corresponds to n=2, but what about the elements in period 4? Would K and Ca be in the fourth energy shell (n=4) and then Sc, Ti, and the rest of the d-block elements would be in the third energy shell (n=3)? Or does the ...
by Julia Nakamura 2D
Mon Oct 10, 2016 10:47 am
Forum: DeBroglie Equation
Topic: #9 on practice test [ENDORSED]
Replies: 3
Views: 524

Re: #9 on practice test [ENDORSED]

I also thought that it should be three sig figs, since the lowest given values are 0.155 (which has 3 sig figs) and 85.0 (which also has 3 sig figs). Because this is a problem involving multiplication and division, you would use 3 sig figs, but I think that they just gave a general answer at the end...
by Julia Nakamura 2D
Mon Oct 03, 2016 8:06 pm
Forum: Properties of Electrons
Topic: Constructive and Destructive Interference [ENDORSED]
Replies: 3
Views: 950

Re: Constructive and Destructive Interference [ENDORSED]

Two waves are said to be acting in phase, or in constructive interference, when the peak of one wave aligns with the peak of another wave (or the trough of one wave aligns with the trough of another wave). This interaction will create bigger peaks and troughs. However, two waves act out of phase, or...
by Julia Nakamura 2D
Mon Oct 03, 2016 9:12 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Online module assessment solutions
Replies: 2
Views: 400

Re: Online module assessment solutions

The answers cannot be found online, so I would recommend going to office hours! At the beginning of each of the post-module online assessments, it says, "* Answers are not given at the end of the assessment."
by Julia Nakamura 2D
Mon Sep 26, 2016 9:37 pm
Forum: Photoelectric Effect
Topic: Photo electric effect
Replies: 3
Views: 486

Re: Photo electric effect

Yes, the mass of the electron will be given to you (with the correct number of sig figs that you should use). The mass that I used for that problem was 9.11 x 10^-31. So, multiplying the mass of the electron times the velocity (6.61 x 10^5)^2 and dividing by two should give you 1.99 x 10^-19 J as th...
by Julia Nakamura 2D
Sun Sep 25, 2016 8:03 pm
Forum: Empirical & Molecular Formulas
Topic: Determining Empirical Formula from Ball and Stick Structures [ENDORSED]
Replies: 1
Views: 1421

Re: Determining Empirical Formula from Ball and Stick Structures [ENDORSED]

So as you said you already know, the molecular formulas are: a) C4H6Cl2 b) C2H8N2 So to find the empirical formulas, all that you need to do is divide each of the molecular formulas by their greatest common factor. So for a) it would be 2 and for b) it would also be 2. So then your answers would be:...

Go to advanced search