Search found 45 matches

by Natalie Yakobian
Tue Mar 08, 2016 5:32 pm
Forum: *Electrophilic Addition
Topic: question 5A 2012 practice final
Replies: 1
Views: 377

question 5A 2012 practice final

HI,
I am a little lost on question 5A on where the arrows go for step C -> D. Can someone please explain or show me a picture or their work?
Thank you so much!
by Natalie Yakobian
Mon Mar 07, 2016 10:24 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Trans vs Cis stablity
Replies: 3
Views: 455

Re: Trans vs Cis stablity

Thanks! However, what if the Trans has both substituents in equatorial position?
by Natalie Yakobian
Mon Mar 07, 2016 10:15 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Trans vs Cis stablity
Replies: 3
Views: 489

Trans vs Cis stablity

For cyclohexanes in chair postion is Trans always more stable than cis?

Thanks!
by Natalie Yakobian
Mon Mar 07, 2016 10:15 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Trans vs Cis stablity
Replies: 3
Views: 455

Trans vs Cis stablity

For cyclohexanes in chair postion is Trans always more stable than cis?

Thanks!
by Natalie Yakobian
Sat Mar 05, 2016 8:41 pm
Forum: *Alkanes
Topic: Functional groups we have to know
Replies: 4
Views: 577

Functional groups we have to know

Hi I was wondering in the organic textbook there are more functional groups than we went over in class. Will we be responsible for knowing those as well?

Thanks!
by Natalie Yakobian
Thu Mar 03, 2016 3:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Video Competition
Replies: 66
Views: 24932

Video Competition: Solving Intergrals

The Magic of Chem. with Professor Laurence Lavelle (Dr. Wizard L. L.).mp4 [ 24.72 MiB | Viewed 21825 times ]





By:
Dahriel Aron
Natalie Yakobian
Erin Min


Alternate Viewing option through youtube:
https://www.youtube.com/watch?v=W9iU_kyAkCI
by Natalie Yakobian
Sun Feb 28, 2016 5:54 pm
Forum: *Alkanes
Topic: Tricks for structural Isomers
Replies: 1
Views: 1045

Tricks for structural Isomers

Hi!
Does anyone know some good tricks for identifying how many and what structural isomers we should draw?

Thanks
by Natalie Yakobian
Sat Feb 27, 2016 3:38 pm
Forum: *Alkenes
Topic: (E)-1,1-Bromochloropropene and (Z)-1,1,Bromochloropropene
Replies: 1
Views: 292

(E)-1,1-Bromochloropropene and (Z)-1,1,Bromochloropropene

Can someone please explain the difference between (E)-1,1-Bromochloropropene and (Z)-1,1,Bromochloropropene . Why are the not both E because the propriety groups are on the same side.

Thanks so much!
by Natalie Yakobian
Thu Feb 25, 2016 11:19 pm
Forum: *Alkenes
Topic: Self Test 1.5B
Replies: 1
Views: 252

Self Test 1.5B

Hi I was wondering if anyone understood what the question from Self Test 1.5B was asking for. It asks us to identify 2-methyl-1,3-butadiene but I don't see any possible structure for that in Limonene. Each molecule seems to only have 1 single bond. What am I doing wrong?

Thanks so much!
by Natalie Yakobian
Thu Feb 25, 2016 11:17 pm
Forum: *Alkenes
Topic: Naming alkenes
Replies: 3
Views: 405

Re: Naming alkenes

It can also be included before the ene part of the name.

So for 3,6-dimethyl-3-octone where 3 is the the number of the carbon the double bond starts at you can also write it as 3,6-dimethyloct-3-ene.
by Natalie Yakobian
Wed Feb 24, 2016 10:37 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Electrophilic aromatic substitution equilibrium?
Replies: 1
Views: 326

Electrophilic aromatic substitution equilibrium?

Hi
I was wondering for electrophilic aromatic substitution why is the slow step in equilibrium? \

Thanks!
by Natalie Yakobian
Wed Feb 24, 2016 9:28 pm
Forum: *Organic Reaction Mechanisms in General
Topic: intermediates in the rate law HW 4.31
Replies: 1
Views: 304

intermediates in the rate law HW 4.31

Hi,
I was wondering from 4.31 in the second step we use intermediates in the rate law. Why is this ok?
Thanks so much.
by Natalie Yakobian
Tue Feb 16, 2016 6:10 pm
Forum: General Rate Laws
Topic: Units question
Replies: 2
Views: 380

Units question

Hi I was wondering for the time of rates does time need to be in minutes or can it be in seconds?

Thank you!
by Natalie Yakobian
Mon Feb 15, 2016 2:56 pm
Forum: General Rate Laws
Topic: Difference between finding general rate and using rate laws
Replies: 1
Views: 291

Difference between finding general rate and using rate laws

Hi,
I'm confused as to the difference between finding the rate of reaction using the formula 1/a[A]/deltaT or by finding it through rate law formulas like first, second, zero order.

Can someone please explain this?


Thank you!
by Natalie Yakobian
Sat Feb 06, 2016 12:24 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Entropy Question Practice midterm 2013 5B
Replies: 1
Views: 318

Entropy Question Practice midterm 2013 5B

Hi, I am confused with question 5B on the 2013 midterm. It asks us to put the following substances in increasing order of standard molar entropy CHF3, CF4, CH3F, CH2F2 I have to conflicting thoughts on this problem. I understand that heavier molecules have higher molar entropy so CF4 would have the ...
by Natalie Yakobian
Fri Feb 05, 2016 2:48 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Balancing chemical equations for Delta Gr
Replies: 1
Views: 270

Balancing chemical equations for Delta Gr

Hi, I was wondering when your balancing chemical equations for Delta Gr are there any rules like there are for Gf, or delta Hf, where you must have only one mol of product so reactant coefficients may need to be in fraction form? For example in one of the past midterms (2012 question 6A) the reactan...
by Natalie Yakobian
Sun Jan 31, 2016 5:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Importance of Emax
Replies: 1
Views: 301

Importance of Emax

What is the importance of saying that it is the maximum amount of potential or work being done?
by Natalie Yakobian
Sun Jan 24, 2016 5:44 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Past quiz 2015 question 9
Replies: 1
Views: 270

Past quiz 2015 question 9

Hi, For the past quiz numbr 9: A sample of 1 mol of gas initially at 1 atm and 298 K is heated at constant pressure to 350 K then the gas is compressed isothermally to its initial volume and finally it is cooled to 298 K at constant volume. I understand why Delta G and Delta S of system are 0 becaus...
by Natalie Yakobian
Sat Jan 23, 2016 12:49 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: HW 9.25: Understanding Molor disorder of crystals
Replies: 4
Views: 743

HW 9.25: Understanding Molor disorder of crystals

Hi I am having trouble with HW 9.25 "If SO2F2 adopts a positionally disordered arrangement in its crystal form, what might its residual molar entropy be?" How do we determine the possible number of positions? Also whenever it says molar entropy do we always use avogadro's number? Thanks so...
by Natalie Yakobian
Wed Jan 20, 2016 12:22 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy for changing Temperature
Replies: 1
Views: 175

Entropy for changing Temperature

HI I was wondering, In the book for changing temperature the only formula given to calculate it was deltaS = Cln(T2/T1) , But in the solution manual for question number 9.13 they use the formula DeltaS =nRln(T2/T1). Wouldn't we instead use Cv = 3/2R and then plug that into the first equation? Thank ...
by Natalie Yakobian
Mon Jan 18, 2016 5:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: When is change in internal energy 0?
Replies: 1
Views: 318

When is change in internal energy 0?

When is change in internal energy 0? Is it it only when it says that it's isothermal?

Thank You
by Natalie Yakobian
Mon Jan 18, 2016 11:52 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Irreversible vs Reversible processes
Replies: 1
Views: 369

Irreversible vs Reversible processes

Hi
I was wondering if someone could explain Irreversible vs Reversible processes?

Thanks!
by Natalie Yakobian
Tue Jan 12, 2016 10:16 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Kekulé structures
Replies: 1
Views: 282

Kekulé structures

Hi,
I noticed in the book and on one of the homework questions (8.77) they mention Kekule structures but this is not in our course reader. Will we need to know this for the quiz and exam? Also would someone mind explaining to me what exactly they are?

Thank you!
by Natalie Yakobian
Sun Jan 10, 2016 2:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: HW question 8.49
Replies: 1
Views: 216

HW question 8.49

Hi I am very confused with question 8.49 Oxygen dif uoride is a colorless, very poisonous gas that reacts rapidly with water vapor to produce O2, HF, and heat. What is the change in internal energy for the reaction of 1.00 mol OF2? I know that deltaU = DeltaH - deltanxRxT, and that delta n is 1 base...
by Natalie Yakobian
Sun Jan 10, 2016 2:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Question 8.31: a monatomic ideal gas at constant P or V
Replies: 2
Views: 445

Re: Question 8.31: a monatomic ideal gas at constant P or V

Hi,
For Gas molecules at

Constant Pressure the Heat Capacity can be found by the formula (5/2)R

Constant Volume the Heat Capacity can be found by the formula (3/2)R

We use this to get the Cm in this problem so then we can find q = nxCmxdeltaT

Hope this helps
by Natalie Yakobian
Sat Jan 09, 2016 3:38 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework 8.25
Replies: 5
Views: 2924

Homework 8.25

Hi, I was wondering how to solve homework question 8.25. "A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q= -3.50 kJ), resulting in a temperature rise of 7.32 C. In a subsequent experiment, 100....
by Natalie Yakobian
Sat Jan 09, 2016 11:05 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Change in internal energy: Really Big or Really Small
Replies: 1
Views: 266

Change in internal energy: Really Big or Really Small

Hi, I was wondering if you have a really large negative change in interal energy and a smaller negative change in internal energy which one would be considered greater? It seems to me that the negative sign just tells us whether energy is used or gained so the negative sign doesn't matter in terms o...
by Natalie Yakobian
Thu Dec 03, 2015 4:20 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Depronatation
Replies: 1
Views: 323

Depronatation

Why is the percentage deprotonation of benzoic acid in a benzoic acid solution decreased when hydrochloric acid?

Wouldn't the H30+ interact with the conjugate base of benzoic acid?

Thank you!
by Natalie Yakobian
Tue Dec 01, 2015 5:17 pm
Forum: Polyprotic Acids & Bases
Topic: HW 12.77 (Calculating pH of alanine)
Replies: 3
Views: 667

Re: HW 12.77 (Calculating pH of alanine)

HI,
I was wondering how do you know that it should be thought of as a titration problem?
by Natalie Yakobian
Tue Dec 01, 2015 2:48 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: How to tell if something is a conjugate base/acid
Replies: 1
Views: 498

How to tell if something is a conjugate base/acid

Hello,
How do you tell if something is a congugagte base/acid?

For example CH3NH3Cl. How would I know that this is the conjugate acid of CH3NH2?
Would I just imagine the Cl dissociating and then realize that CH3NH2?

Thanks!!
by Natalie Yakobian
Thu Nov 26, 2015 5:13 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig Figs for calculating pOH and pH
Replies: 1
Views: 666

Sig Figs for calculating pOH and pH

Hi,
I was wondering when calculating pOH and pH do we consider sig figs?

It seems from the book questions that they don't.

Thanks so much!
by Natalie Yakobian
Sat Nov 21, 2015 10:49 pm
Forum: Bronsted Acids & Bases
Topic: How to know if something dissolves into an Acid or Base
Replies: 2
Views: 387

How to know if something dissolves into an Acid or Base

HI,
If you are given a reaction and asked if it is a acid/base reaction do you have to take into account whether or not the chemical compounds are soluble? Should we memorize solubility rules?

For example question 12.9 asks us to write the net ionic equations.
by Natalie Yakobian
Sun Nov 15, 2015 1:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sig Figs for Equilibrium Constants
Replies: 1
Views: 278

Sig Figs for Equilibrium Constants

Hi I was wondering do we count the number of sig in K?

For example in problem 11.117 K has two sig figs but the final answer has 3. Why is this?
by Natalie Yakobian
Wed Nov 11, 2015 2:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure vs Molarity
Replies: 1
Views: 353

Partial Pressure vs Molarity

Hi, When were dealing with a Equilibrium Constant problem where all products and reactants are gas do we have to first convert to partial pressure and then solve it, or are we allowed to convert to molarity to solve it? For example in the book Example 11.8 we are given grams of gas and a volume. The...
by Natalie Yakobian
Tue Nov 10, 2015 11:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework question 11.7 help!
Replies: 1
Views: 364

Homework question 11.7 help!

The following flasks show the dissociation of a diatomic molecule, X2, over time. (a) Which flask represents the point in time at which the reaction has reached equilibrium?(b) What percentage of the X2 molecules have decomposed at equilibrium? (c) Assuming that the initial pressure of X2 was 0.10 ...
by Natalie Yakobian
Tue Nov 03, 2015 10:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle of square pyramidal
Replies: 5
Views: 4139

Re: Bond angle of square pyramidal

Why would the lone pair of electrons not make everything <90 ?
Thanks so much!
by Natalie Yakobian
Tue Nov 03, 2015 3:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle of square pyramidal
Replies: 5
Views: 4139

Bond angle of square pyramidal

Hello,
I was wondering if the bond angle square pyramidal is 180, 90 or if it is slightly less than 180, 90.

Thanks so much!
by Natalie Yakobian
Sat Oct 31, 2015 6:09 pm
Forum: Hybridization
Topic: Sigma and Pi bond question
Replies: 1
Views: 335

Sigma and Pi bond question

For C2H4 a Carbon Carbon double bond why is the sigma bond (C2sp^3,C2sp^3) and the Pi bond (C2P, C2P)?
by Natalie Yakobian
Sun Oct 25, 2015 3:25 pm
Forum: Bond Lengths & Energies
Topic: Question on Homework Problem 3.89 B, Urea
Replies: 2
Views: 464

Re: Question on Homework Problem 3.89 B, Urea

Thank you! Is this always the case with a central atom? If its in the middle does and has a double bond with one molecule and a single bond with another does it take on the value of a double bond?
by Natalie Yakobian
Sun Oct 25, 2015 3:23 pm
Forum: Hybridization
Topic: Chapter 4 question 1 help please
Replies: 2
Views: 461

Chapter 4 question 1 help please

bellow are ball and stick models of two molecules, in each case, indicate where there must be, may be, or cannot be one or more lone pairs of electrons on the central atom The picture is of a trigonal planar molecule with 120 degrees between it and then a linear molecule with 180 degrees But if the...
by Natalie Yakobian
Wed Oct 21, 2015 12:44 am
Forum: Bond Lengths & Energies
Topic: Question on Homework Problem 3.89 B, Urea
Replies: 2
Views: 464

Question on Homework Problem 3.89 B, Urea

Use the information in Fig. 3.21 to estimate the bond length of (a) the CO bond in CO2; (b) the CO and CN bonds in urea, OC(NH2)2; (c) the OCl bond in HClO; (d) the NCl bond in NOCl. Hi, There was a similar question on this about how to solve these. However the post said that the answer to b would ...
by Natalie Yakobian
Fri Oct 16, 2015 10:31 am
Forum: Resonance Structures
Topic: Resonance Structures Question
Replies: 1
Views: 256

Resonance Structures Question

Hi,
I was wondering if someone could please explain the concept of a partial double bond?
Thanks so much.
by Natalie Yakobian
Thu Oct 08, 2015 1:13 pm
Forum: Trends in The Periodic Table
Topic: Effective Nuclear Charge
Replies: 1
Views: 354

Effective Nuclear Charge

Hi I'm a little unclear on what Zeff is. Can someone please explain it to me?

Thanks
by Natalie Yakobian
Tue Sep 29, 2015 6:39 pm
Forum: Properties of Electrons
Topic: Question number 1.15
Replies: 1
Views: 531

Question number 1.15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. For this question I was able to find the two energy level by trail and er...

Go to advanced search