## Search found 45 matches

- Fri Mar 11, 2016 8:57 am
- Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
- Topic: Trans vs Cis stablity
- Replies:
**3** - Views:
**489**

### Re: Trans vs Cis stablity

Thanks!

- 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!

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!

- 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?

- 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!

Thanks!

- 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!

Thanks!

- 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!

Thanks!

- Thu Mar 03, 2016 3:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Video Competition
- Replies:
**66** - Views:
**24932**

### Video Competition: Solving Intergrals

By:

Dahriel Aron

Natalie Yakobian

Erin Min

Alternate Viewing option through youtube:

https://www.youtube.com/watch?v=W9iU_kyAkCI

- 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

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

Thanks

- 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!

Thanks so much!

- 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!

Thanks so much!

- 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.

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.

- 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!

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

Thanks!

- 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.

I was wondering from 4.31 in the second step we use intermediates in the rate law. Why is this ok?

Thanks so much.

- 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!

Thank you!

- 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!

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!

- 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 ...

- 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...

- 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?

- 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...

- 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...

- 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 ...

- 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

Thank You

- 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!

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

Thanks!

- 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!

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!

- 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...

- 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

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

- 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....

- Sat Jan 09, 2016 11:05 am
- 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...

- 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!

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

Thank you!

- 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?

I was wondering how do you know that it should be thought of as a titration problem?

- 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!!

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!!

- 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!

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!

- 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.

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.

- 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?

For example in problem 11.117 K has two sig figs but the final answer has 3. Why is this?

- 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...

- 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 ...

- 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!

Thanks so much!

- 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!

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

Thanks so much!

- 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)?

- 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?

- 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...

- 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 ...

- 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.

I was wondering if someone could please explain the concept of a partial double bond?

Thanks so much.

- 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

Thanks

- 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...