Search found 21 matches
- Tue Mar 14, 2017 5:21 pm
- Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
- Topic: Intro to O-CHEM CH.1 Problem #28
- Replies: 1
- Views: 443
Re: Intro to O-CHEM CH.1 Problem #28
It is trans because if you're looking at the C-C double bond alone, and the rest of the chain as a substituent, then the bottom right substituent would be 2methyl-butane and the top left would be ethyl, which have higher priorities than the methyls on the top right and bottom left, therefore it is t...
- Thu Mar 09, 2017 5:40 pm
- Forum: *Alkenes
- Topic: Priority in Alkenes
- Replies: 2
- Views: 632
Re: Priority in Alkenes
Page 16 Toolbox 1.1 in the Introduction to Organic Chemistry explains how to determine priority. It says that priority is based on the atomic number of the atom bound to the sp2 carbon atom; so for 1.26, Br has an atomic number 35 while the methyl group has less priority than the ethyl group sharing...
- Thu Mar 09, 2017 12:00 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: (S)-isomer and (R)-isomer
- Replies: 2
- Views: 617
Re: (S)-isomer and (R)-isomer
Okay that clears things up. Thank you
- Thu Mar 02, 2017 8:02 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: (S)-isomer and (R)-isomer
- Replies: 2
- Views: 617
(S)-isomer and (R)-isomer
What are the significant differences between the formation of an (S)-isomer and an (R)-isomer?
- Fri Feb 24, 2017 11:05 am
- Forum: Second Order Reactions
- Topic: Third Order Reactions
- Replies: 5
- Views: 1555
Re: Third Order Reactions
The hydrolysis of sucrose in acid solution is third-order, r = k[sucrose][H+][H2O]; however, the concentrations of both the catalyst H+ and the solvent H2O are normally constant, so that the reaction is pseudo–first-order.
- Sun Feb 19, 2017 12:01 am
- Forum: General Rate Laws
- Topic: Quiz 2 preparation #2
- Replies: 2
- Views: 538
Re: Quiz 2 preparation #2
Reaction Rate is the change in concentration of reactants or the change in concentration of products divided by the time interval over which the change takes place. The rate constant (k) for the reaction is characteristic of the reaction (different reactions have different rate constants) and the te...
- Thu Feb 09, 2017 9:59 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 1
- Views: 522
Re: Nernst Equation
It's actually supposed to be 0.025693V and it comes from calculating RT/F. It's really just a constant by multiplying other constants together.
- Thu Feb 02, 2017 11:31 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Higher Entropy
- Replies: 2
- Views: 818
Re: Higher Entropy
This is from a post about a year ago: "S(gas) >> S(liquid) > S(solid), always. For the same state, to compare entropy, think of the equation S = klnW (where k is Boltzmann's constant). W = (number of states)^(number of particles). With the same amount of moles, monatomic gases have more entropy...
- Sat Jan 28, 2017 3:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Problem 8.43
- Replies: 1
- Views: 509
Re: Problem 8.43
I believe it's because on option C, the heat capacities for the solid and gas are better represented in that they are more equal in slope and length than compared to option B
- Sat Jan 21, 2017 3:54 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Born-Haber Cycle [ENDORSED]
- Replies: 1
- Views: 565
Born-Haber Cycle [ENDORSED]
Are the Born-Haber Cycle and lattice enthalpy going to be applied during this course?
- Fri Jan 13, 2017 1:46 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpy Question Help
- Replies: 1
- Views: 445
Re: Bond Enthalpy Question Help
When drawing out the Lewis structures for the reactants, it can be seen that the only bonds broken are between the C=C of the CH2 molecules and the bond between the H and Br atom. For the products, only one C-H bond is formed from the broken bond in the reactants, which is taken into account in the ...
- Fri Dec 02, 2016 10:20 am
- Forum: Calculating the pH of Salt Solutions
- Topic: Henderson Hasslebach Equation
- Replies: 1
- Views: 651
Re: Henderson Hasslebach Equation
It's essentially the same equation, but using base and conjugate acid:
ph=pKb + log (conjugate acid concentration / concentration of b) or
ph=pKb + log (BH^+/B)
ph=pKb + log (conjugate acid concentration / concentration of b) or
ph=pKb + log (BH^+/B)
- Wed Nov 23, 2016 12:23 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Keeping Equilibrium with Pressure
- Replies: 2
- Views: 693
Re: Keeping Equilibrium with Pressure
If the pressure of a system is INCREASED, the reaction will shift toward the side with fewer moles of GAS. If the pressure of a system is DECREASED, the reaction will shift toward the side with more moles of GAS. If the moles of gas reactants is equal to the moles of gas reactants, a change in press...
- Fri Nov 18, 2016 7:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 11.7 c
- Replies: 1
- Views: 460
Re: 11.7 c
I'm pretty certain that part c is very similar to calculating the equilibrium composition where you are given the initial pressure, in this case .10 bar, and you are trying to find the change in pressure to get the equilibrium decomposition pressure.
- Thu Nov 10, 2016 11:48 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Drawing MO diagrams
- Replies: 2
- Views: 657
Drawing MO diagrams
When drawing MO diagrams for atoms in Period 3, is it necessary to draw the 2nd shell Molecular orbitals in addition to the 3rd shell molecular orbitals?
- Fri Nov 04, 2016 10:24 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: MO Diagram
- Replies: 1
- Views: 417
Re: MO Diagram
Because the nuclear charge is less, the energy difference between the filled s-orbital and p-orbitals is less. Remembering that the electron density from filled sigma(s) and sigma*(s) orbital is concentrated along the bond axis, and since the sigma(Pz) orbital is also directed along bond axis, there...
- Thu Oct 27, 2016 9:58 pm
- Forum: Trends in The Periodic Table
- Topic: Question 93, Chapter 2 [ENDORSED]
- Replies: 2
- Views: 647
Re: Question 93, Chapter 2 [ENDORSED]
If you look at this link,
https://lavelle.chem.ucla.edu/wp-conten ... rs_6Ed.pdf
it will show you the errors in the solution manual, and Question 2.93 is one of them.
https://lavelle.chem.ucla.edu/wp-conten ... rs_6Ed.pdf
it will show you the errors in the solution manual, and Question 2.93 is one of them.
- Fri Oct 21, 2016 10:32 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Chapter 2 Homework #15
- Replies: 1
- Views: 1306
Re: Chapter 2 Homework #15
I'm pretty sure that the solution manual is incorrect for this problem. Based on a few websites as well, they all say that the 3-p orbital has only one radial node, with two nodal planes in total. According to http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Quantum_Mechanics/09._T...
- Fri Oct 14, 2016 12:28 pm
- Forum: General Science Questions
- Topic: # of Molecules
- Replies: 3
- Views: 911
Re: # of Molecules
Yep. Because the molecular formula shows the actual number of atoms of a molecule.
- Thu Oct 06, 2016 10:49 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G5 [ENDORSED]
- Replies: 2
- Views: 910
Re: G5 [ENDORSED]
So you're trying to find the volume and you have the moles for Na (for part a) and the molarity. Using stoichiometry, start with 2.15mmol Na divided by the molarity you found (.07967M) and then multiply that by the ratio of moles of Na2CO2 (1 mol) to Na (2 mol), giving you 13.5mL. You repeat this fo...
- Fri Sep 30, 2016 10:13 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity & Volume
- Replies: 1
- Views: 474
Re: Molarity & Volume
When calculating molarity, the only information you should need about the solute is the amount of moles of solute you have or need, and this may require you to know how many grams of solute you have depending on what you're given. So no, you do not account for the volume of the solid.