Search found 45 matches

by Rachel Lipman
Sat Mar 12, 2016 10:38 pm
Forum: *Calculations Using ΔG° = -RT ln K
Topic: Vocabulary
Replies: 5
Views: 1470

Re: Vocabulary

Yes. Remember in regards to the graphs. It helps!
by Rachel Lipman
Fri Mar 11, 2016 5:45 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional strain
Replies: 4
Views: 582

Re: Torsional strain

Is it possible to have negative strain at all?
by Rachel Lipman
Mon Mar 07, 2016 1:12 pm
Forum: *Nucleophiles
Topic: Double Bonds
Replies: 3
Views: 348

Re: Double Bonds

It is also easy to note that the double bond is what will be broken to provide electrons to the electron deficient molecule (electrophile).
by Rachel Lipman
Sun Mar 06, 2016 2:55 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Trans and Cis
Replies: 2
Views: 476

Re: Trans and Cis

I believe the drawing must be provided in any case this question would come up. The only way to tell the difference is really through the lewis structure of the molecule.
by Rachel Lipman
Tue Mar 01, 2016 11:16 pm
Forum: *Cycloalkanes
Topic: Quiz 3
Replies: 2
Views: 429

Re: Quiz 3

Yes. The only difference with alkenes and cycloalkenes is a double bond. Just keep an eye out for double bonds and then you know to change the ane to ene.

It is also in the reading for chapter 1 assigned for the quiz.
by Rachel Lipman
Mon Feb 29, 2016 11:06 pm
Forum: *Cycloalkenes
Topic: Dienes
Replies: 1
Views: 235

Re: Dienes

I cannot say for certain if we will need to include conjugated or unconjugated, but just know to label diene for two double bonds and triene for three and so on.
by Rachel Lipman
Sun Feb 28, 2016 1:53 pm
Forum: *Nucleophiles
Topic: Nucleophile strength?
Replies: 2
Views: 331

Re: Nucleophile strength?

In a question of say "which is more nucleophilic" or say "which is the stronger nucleophile" you must look at polarizability of the elements in question. The higher the polarizability (the more electrons, the more free flowing) the stronger the nucleophile.
by Rachel Lipman
Thu Feb 25, 2016 11:24 pm
Forum: *Electrophiles
Topic: Electrophiles vs Nucelophiles
Replies: 2
Views: 318

Electrophiles vs Nucelophiles

Any quick tips on determining whether an element/compound is an electrophile or nucleophile?
by Rachel Lipman
Wed Feb 24, 2016 10:44 am
Forum: *Alkanes
Topic: Naming with Multplie Substituents
Replies: 2
Views: 214

Re: Naming with Multplie Substituents

Prefixes on the substituents do not affect the order of the substituents in the final compound name. Remember: the substituents are always alphabetical order disregarding their prefixes.
by Rachel Lipman
Wed Feb 24, 2016 10:43 am
Forum: *Alkanes
Topic: IUPAC
Replies: 3
Views: 360

Re: IUPAC

One thing to remember when listing the substituents alphabetically is that no matter the prefix placed in front of the substituent, they are still listed in alphabetical order. In simpler terms, the prefix does not affect the listing order of substituents.
by Rachel Lipman
Mon Feb 22, 2016 1:28 pm
Forum: *Electrophiles
Topic: Memory Tips
Replies: 8
Views: 893

Re: Memory Tips

In class today it was mentioned that nucleophiles are basically another term for Lewis bases, so if you can remember that you can make the distinction that nucleophiles are electron rich.
by Rachel Lipman
Tue Feb 16, 2016 5:16 pm
Forum: Second Order Reactions
Topic: Linear Graphs
Replies: 5
Views: 4818

Re: Linear Graphs

There have been no graph questions in the textbook homework, so I was wondering what some examples might be to prepare should it show up on our quiz?
by Rachel Lipman
Tue Feb 16, 2016 4:10 pm
Forum: *Electrophiles
Topic: Why F, Cl, Br, I are electrophiles?
Replies: 4
Views: 914

Re: Why F, Cl, Br, I are electrophiles?

Thank you so much for the clarification.
by Rachel Lipman
Mon Feb 15, 2016 3:56 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Textbook Problems 15.3 and 15.5
Replies: 7
Views: 497

Re: Textbook Problems 15.3 and 15.5

In the solutions manual, 15.3 part c is depicted as the second b.
by Rachel Lipman
Sat Feb 13, 2016 11:04 pm
Forum: *Electrophiles
Topic: Why F, Cl, Br, I are electrophiles?
Replies: 4
Views: 914

Re: Why F, Cl, Br, I are electrophiles?

May you further elaborate on what electrophiles are and what are the determining factors?
by Rachel Lipman
Sun Feb 07, 2016 8:11 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Equation
Replies: 5
Views: 1063

Re: Van't Hoff Equation

What type of wording in a question would lead us to use this equation?
by Rachel Lipman
Thu Feb 04, 2016 5:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Discerning what is being reduced and oxidized? HW 14.15a
Replies: 2
Views: 316

Re: Discerning what is being reduced and oxidized? HW 14.15a

Anytime an element is alone such as Ag is the charge is 0? Is that the best way to determine in a situation like this reaction what is the anode and what is the cathode?
by Rachel Lipman
Thu Feb 04, 2016 5:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing Cell diagram with Pt
Replies: 2
Views: 338

Re: Writing Cell diagram with Pt

When the reaction does not have conducting solids, platinum or graphite, both inert conductors, are incorporated into the cell diagram as an electrode to transfer electrons.
by Rachel Lipman
Thu Feb 04, 2016 5:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagram: figuring out order
Replies: 2
Views: 276

Re: Writing cell diagram: figuring out order

I typically just remember it having the solids on the outermost part of the cell diagram.
by Rachel Lipman
Tue Feb 02, 2016 6:40 pm
Forum: Balancing Redox Reactions
Topic: Helpful Tip
Replies: 2
Views: 291

Re: Helpful Tip

LOVE THIS! Thank you for sharing!
by Rachel Lipman
Tue Feb 02, 2016 6:39 pm
Forum: Balancing Redox Reactions
Topic: 14.1 Book HW
Replies: 3
Views: 390

Re: 14.1 Book HW

That makes complete sense, but say for question 14.3 where S is technically 2- as well as O, how do you determine that in SO42- that S has to have the oxidation number 6+?
by Rachel Lipman
Mon Feb 01, 2016 9:29 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Useful Summary of Thermodynamic Definitions
Replies: 23
Views: 13441

Re: Useful Summary of Thermodynamic Definitions

This is great! Thank you for sharing these key terms in such a simple and concise way! These terms are essential to memorize for future quizzes and tests.
by Rachel Lipman
Fri Jan 29, 2016 1:50 pm
Forum: Balancing Redox Reactions
Topic: Identifying anodes and cathodes
Replies: 2
Views: 342

Re: Identifying anodes and cathodes

As Lavelle mentioned in class today, the best way is by determining which element is involved in reduction and which is being oxidized. When it comes to oxidation and reduction determining, you must approach the reaction systematically by determining the compound that when reduced will still allow t...
by Rachel Lipman
Fri Jan 29, 2016 1:47 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Extensive and Intensive
Replies: 4
Views: 429

Re: Extensive and Intensive

Pertaining to today's lesson, an extensive property directly involves how much of a something is presented in a reaction, while with an intensive property, the amount present in essentially irrelevant to the concluding calculations.
by Rachel Lipman
Sun Jan 24, 2016 6:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Approach to Bond Enthalpies
Replies: 1
Views: 159

Approach to Bond Enthalpies

Is the only way to approach a question asking one to solve for the bond enthalpies by first drawing out the lewis structures and determining where bonds are broken and formed? Is there a simpler way to go about solving these problems? What is the best method overall?
by Rachel Lipman
Sat Jan 23, 2016 9:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: How to find enthalpy of rxn using enthalpies of formation?
Replies: 2
Views: 313

Re: How to find enthalpy of rxn using enthalpies of formatio

I was just reviewing this question as well, so basically because O2 and N2 are not included in the overall calculation of enthalpy because "by definition, the standard enthalpy of formation of an element in its most stable form is zero."
by Rachel Lipman
Sat Jan 23, 2016 10:55 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculating q (Enthalpy)
Replies: 2
Views: 236

Re: Calculating q (Enthalpy)

If q is provided with units including mol-1/grams-1, then incorporating n into the final equation is incorrect. It is essential to look at the units for every calculated value in order to implement the right equations. I suggest ALWAYS writing out units for every number that way it is easy to notice...
by Rachel Lipman
Sat Jan 23, 2016 10:50 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculating the energy changes when heating an ideal gas
Replies: 2
Views: 288

Re: Calculating the energy changes when heating an ideal gas

Have we seen any examples in the course reader or textbook in which we needed to implement the linear/nonlinear molecule equations?
by Rachel Lipman
Sun Jan 17, 2016 1:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework Problem 8.73
Replies: 4
Views: 618

Re: Homework Problem 8.73

Thank you Reine. An addition question I have is about calculating bond enthalpies in general. Is it most cases that bonds are broken and new ones formed?
by Rachel Lipman
Thu Jan 14, 2016 3:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework Problem 8.73
Replies: 4
Views: 618

Homework Problem 8.73

Starting with example (a), I understand the Carbon bonds are being broken, however, I am confused why the solutions manual explains the Carbon-Carbon bonds being broken as triple bonds. When I consult the Mean Bond Enthalpies Table (8.7), there are a few options for Carbon-Carbon bonds. Is there a c...
by Rachel Lipman
Sun Jan 10, 2016 5:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 2
Views: 292

Re: bond enthalpies

An endothermic reaction occurs when it takes more energy to break bonds in the reactants than what is released when new bonds for in the products. An exothermic reaction occurs when more energy is released when new bonds form in products than what is used when bonds in the reactants are broken. It i...
by Rachel Lipman
Sat Dec 05, 2015 9:10 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strength of acids/ bases
Replies: 3
Views: 496

Re: strength of acids/ bases

I would memorize the 6 strong acids in the course reader, there really are not many more beyond those. (hydrochloric acid - HCl, hydrobromic acid - HBr, hydroiodic acid - HI, sulfuric acid - H2SO4, nitric acid - HNO3, perchloric acid - HClO4).
by Rachel Lipman
Sat Dec 05, 2015 8:37 pm
Forum: Conjugate Acids & Bases
Topic: NH4+ and NH3
Replies: 3
Views: 3500

Re: NH4+ and NH3

It pertains the the conjugate seesaw rule: the stronger the acid, the weaker the conjugate base; the stronger the base, the weaker the conjugate acid.
by Rachel Lipman
Mon Nov 30, 2015 7:57 pm
Forum: Conjugate Acids & Bases
Topic: Percentage Deprotonated
Replies: 3
Views: 520

Re: Percentage Deprotonated

Great thank you. But in other cases the ratio is not always one-to-one? And sometimes A- is not equivalent to H3O+?
by Rachel Lipman
Sun Nov 29, 2015 3:16 pm
Forum: Conjugate Acids & Bases
Topic: Percentage Deprotonated
Replies: 3
Views: 520

Percentage Deprotonated

When calculating the percentage, it is the concentration of A- divided by the initial concentration of HA times 100%. In the textbook it says it is also H3O+ divided by initial concentration. I am confused because when making the ice block chart, H3O+ is different than A-. Clarification please...
by Rachel Lipman
Sun Nov 22, 2015 12:57 pm
Forum: Biological Examples
Topic: Important Metals for Biology [ENDORSED]
Replies: 4
Views: 8113

Re: Important Metals for Biology [ENDORSED]

The main ones to note, however, are Iron, Chromium, Cobalt, and Mn, Ni, Cu, Zn.
by Rachel Lipman
Sat Nov 21, 2015 2:37 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Weak acids and equations
Replies: 3
Views: 509

Re: Weak acids and equations

Are Ka and Kb inversely proportional? I remember going over some aspect of the relationship in class...
by Rachel Lipman
Sat Nov 21, 2015 2:35 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Equilibrium Constant
Replies: 7
Views: 771

Re: Equilibrium Constant

Is it then that Ka and Kb are inversely proportional?
by Rachel Lipman
Sat Nov 14, 2015 1:54 pm
Forum: Naming
Topic: Naming of Coordination Compounds
Replies: 2
Views: 186

Re: Naming of Coordination Compounds

Thank you! The case is the same for other anionic elements right? Like cobalt can be cobaltate?
by Rachel Lipman
Fri Nov 13, 2015 9:18 am
Forum: Naming
Topic: Naming of Coordination Compounds
Replies: 2
Views: 186

Naming of Coordination Compounds

In my discussion section earlier this week, we looked at a coordination compound including Iron (Fe). When we named the structure, rather than labeling it iron, instead we named it using its symbol Fe. I am confused about when you call it by its name and when by its symbol with some prefix attached?
by Rachel Lipman
Sat Nov 07, 2015 4:28 pm
Forum: Photoelectric Effect
Topic: Work Function vs De Broglie
Replies: 4
Views: 2390

Work Function vs De Broglie

Looking back at my notes from chapter one, I am confused about when to use just E=hv and when to actually use Ephoton = Ek + work function. Can someone please clarify, especially with the midterm question.
by Rachel Lipman
Mon Nov 02, 2015 1:00 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Schrodinger + MO Theory
Replies: 1
Views: 165

Schrodinger + MO Theory

Can someone please clarify how Schrodinger wave function ties into Molecular Orbital Theory.
by Rachel Lipman
Wed Oct 21, 2015 11:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Shape
Replies: 2
Views: 168

Determining Shape

When determining the shape of a compound, how can it be labeled as both tetrahedral and trigonal pyramidal?
by Rachel Lipman
Mon Oct 12, 2015 5:31 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Overall Charge Calculations
Replies: 1
Views: 359

Overall Charge Calculations

How do you determine which numbers to add/subtract when calculating the overall charge in relation to the Lewis Structure?
by Rachel Lipman
Sun Oct 04, 2015 10:38 pm
Forum: General Science Questions
Topic: Ions
Replies: 1
Views: 539

Ions

What's the difference between a cation and an anion?

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