Search found 19 matches

by Megan Ren 2B
Sun Mar 13, 2016 12:05 pm
Forum: *Alcohols
Topic: 2015 Final 9A second molecule
Replies: 1
Views: 310

2015 Final 9A second molecule

Hi, the answer to the second molecule in 9A of the 2015 final is 1-(3-chlorocycloheptyl)-2-methylpronan-2-ol and I was wondering why the cycloheptane is treated as a substituent here. Is it because the alcohol as the functional group takes priority even though it's on the shorter chain? Thank you!
by Megan Ren 2B
Tue Mar 08, 2016 12:06 am
Forum: *Haloalkenes
Topic: alkynes vs alkenes
Replies: 1
Views: 578

alkynes vs alkenes

I'm a bit confused about the molecule on the top right of page 50 in the organic chemistry textbook. (E)-3-Chloro-4-fluoro-7-methyloct-3-en-5-yne clearly prioritizes the double bond over the triple bond- is this because of the geometric isomers? Does this mean that double bonds are always prioritize...
by Megan Ren 2B
Fri Mar 04, 2016 11:42 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: molecules with odd number of central carbon atoms
Replies: 1
Views: 287

molecules with odd number of central carbon atoms

The two examples that we went over in class were ethane and butane, and I'm wondering what molecules that have an odd number of carbon central atoms look like. For example, would the eclipsed model for butane just look like a straight C-C-C line? Also steric strain can only occur from butane and on ...
by Megan Ren 2B
Sat Feb 20, 2016 12:30 am
Forum: *Nucleophilic Substitution
Topic: double/single-headed arrows
Replies: 6
Views: 1201

double/single-headed arrows

I understand that a double-headed arrow indicates the transfer of two electrons and that a single headed arrow indicates the transfer of one electron, but all the diagrams in the course reader/examples done in class seem to use double-headed arrows anyway. When is it necessary to differentiate betwe...
by Megan Ren 2B
Sun Feb 14, 2016 11:01 pm
Forum: First Order Reactions
Topic: rate laws that depend on the concentration of > 1 species
Replies: 1
Views: 252

rate laws that depend on the concentration of > 1 species

Is there a threshold amount past which it is okay to turn a second order reaction into a pseudo first order reaction? The book uses the example of persulfate ion concentration being 100x greater than that of iodide ions but is there a specific point (i.e. 20x greater concentration, 50x greater, etc.)?
by Megan Ren 2B
Fri Feb 05, 2016 1:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: when are conductors are necessary
Replies: 1
Views: 229

when are conductors are necessary

When writing cell diagrams, how do we know when it is necessary to use a platinum (or other) conductor? (for example, 14.13 parts b and c)
by Megan Ren 2B
Wed Feb 03, 2016 1:38 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: molar convention vs standard cell potential
Replies: 1
Views: 360

molar convention vs standard cell potential

What exactly is the difference between the molar convention for the reaction Gibbs energy and the standard reaction Gibbs free energy? When do we use each?
by Megan Ren 2B
Mon Jan 25, 2016 8:16 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Problem 9.13 (corrected)
Replies: 2
Views: 348

Re: Problem 9.13 (corrected)

Why can't we use Cp? Since the question doesn't say anything about changing pressures, can't we assume that pressure remains constant in part 2 of the reaction as well?
by Megan Ren 2B
Mon Jan 18, 2016 5:40 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond energies and resonance structures
Replies: 1
Views: 407

bond energies and resonance structures

When calculating bond enthalpies for molecules with resonance structures, do we assume resonance or no resonance? (i.e. benzene in 8.73 part a)
by Megan Ren 2B
Mon Jan 18, 2016 4:48 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.51
Replies: 3
Views: 483

Re: Problem 8.51

ah right I didn't notice that thank you!!!
by Megan Ren 2B
Mon Jan 18, 2016 10:48 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.51
Replies: 3
Views: 483

Problem 8.51

Can someone explain why the answer is 23.9 x 10^3 kJ/L and not -23.9 x 10^3 kJ/L? Since it's releasing energy the enthalpy of reaction should be negative, so I don't see how the answer is positive.
by Megan Ren 2B
Sun Jan 10, 2016 1:45 pm
Forum: Phase Changes & Related Calculations
Topic: potential energy vs molecular separation
Replies: 1
Views: 261

potential energy vs molecular separation

Figure 8.21 states "The potential energies of molecules decrease as they approach one another and experience intermolecular attractions, then rise again as the molecules are pressed closely together..." Why is this so? The next sentences states that "the average intermolecular distanc...
by Megan Ren 2B
Fri Dec 04, 2015 9:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: formic acid vs acetic acid
Replies: 1
Views: 615

formic acid vs acetic acid

Why is formic acid stronger than acetic acid?
by Megan Ren 2B
Sat Nov 21, 2015 11:38 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Units for Partial Pressure When Given Kp
Replies: 2
Views: 517

Re: Units for Partial Pressure When Given Kp

Assuming the concentration of reactants was given in terms of molarity, I think it would be okay to use either bar or atm. The book seems to use bar more often though.
by Megan Ren 2B
Mon Nov 02, 2015 1:16 am
Forum: Lewis Structures
Topic: P4 Lewis structure for Ch. 3 #97
Replies: 1
Views: 1114

P4 Lewis structure for Ch. 3 #97

3.97 White phosphorus is composed of tetrahedral molecules of P4 in which each P atom is connected to three other P atoms. Draw the Lewis structure for this molecule. Does it obey the octet rule? The resulting Lewis structure has a kite shape and I'm wondering what's the theory/explanation behind th...
by Megan Ren 2B
Sun Oct 25, 2015 8:03 pm
Forum: Octet Exceptions
Topic: explanation for ClO2 lewis structure (problem 67b)
Replies: 1
Views: 527

explanation for ClO2 lewis structure (problem 67b)

Can someone explain why chlorine is able to violate the octet rule in ClO2?
by Megan Ren 2B
Sun Oct 25, 2015 7:46 pm
Forum: Octet Exceptions
Topic: Double or Single bond in ClO (problem 59, part a)
Replies: 1
Views: 321

Double or Single bond in ClO (problem 59, part a)

Why is the correct lewis structure for number 59 Cl-O drawn with a single bond? The formal charges for Cl and O would be 0 if drawn with a double bond, so that's what I expected the answer to be.
by Megan Ren 2B
Sun Oct 11, 2015 4:50 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau diagrams for elements beginning in period 4
Replies: 1
Views: 265

Aufbau diagrams for elements beginning in period 4

Since electrons are in a lower energy state in the 3d orbital than 4s orbital, would you put 3d below 4s when drawing Aufbau diagrams?
by Megan Ren 2B
Thu Oct 01, 2015 8:46 pm
Forum: Empirical & Molecular Formulas
Topic: Oxygen in Chemical Formulas
Replies: 2
Views: 426

Re: Oxygen in Chemical Formulas

Hi Shweta, for that problem specifically the first sentence reads, "A compound found in the nucleus of a human cell was found to be composed of carbon, hydrogen, oxygen, and nitrogen" in the question. Unless the problem explicitly states it's in the compound, it should be safe to assume it...

Go to advanced search