Search found 19 matches

by Sabina Fridman 1D
Mon Mar 07, 2016 3:40 pm
Forum: *Amines
Topic: Charge of amine
Replies: 1
Views: 777

Re: Charge of amine

i'm pretty sure it's because a quaternary amine is attached to 4 other organic atoms covalently so it only has 4 bonds on it. The nitrogen atom has 5 valence electrons so it's charge would be (5-4)=+1
by Sabina Fridman 1D
Wed Mar 02, 2016 10:05 am
Forum: *Free Energy of Activation vs Activation Energy
Topic: Kinetic vs. Thermodynamic
Replies: 1
Views: 465

Re: Kinetic vs. Thermodynamic

from what I understand: at high temp there is thermodynamic control because it can overcome high Ea and is at reversible conditions and the product will be at a lower energy state and more stable whereas at low temp there is kinetic control because of irreversible conditions and the product will be ...
by Sabina Fridman 1D
Fri Feb 26, 2016 10:32 am
Forum: *Nucleophiles
Topic: Triple bonds
Replies: 3
Views: 449

Re: Triple bonds

could we always differentiate nucleophile v electrophile by the more bonds being the nucleophile?
by Sabina Fridman 1D
Tue Feb 16, 2016 4:52 pm
Forum: General Rate Laws
Topic: Question about Half-Life
Replies: 2
Views: 461

Re: Question about Half-Life

if the equation is second order, then the half life would be: 1/(2[Ainitial])
so to find half life you would use the initial concentration of A given.
by Sabina Fridman 1D
Sat Feb 13, 2016 7:50 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Unique Reaction Rates
Replies: 2
Views: 492

Re: Unique Reaction Rates

so to clarify, the rate of a reaction for products would always be positive and for reactants it would be negative? This doesn't also apply when it asks for the rate of the "consumption of the reactants" because the rate of consumption would be an absolute value yes?
by Sabina Fridman 1D
Sat Feb 06, 2016 5:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 2013 Midterm 3a
Replies: 1
Views: 325

2013 Midterm 3a

In question 3a, we are asked the mass of the water heated and converted to steam. To find this I know we need to add the heat of the water and the heat created by the vaporization of water, but instead of multiplying Hvap by moles, the answer key multiplies by the mass. Can somebody explain how we k...
by Sabina Fridman 1D
Thu Feb 04, 2016 11:33 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Standard potential and K
Replies: 2
Views: 646

Re: Standard potential and K

K is the ratio at equilibrium of [products]/[reactants] so by seeing the ratios of the concentrations of the reaction's products and reactants you would know which equation has a K>1 (pretty much if there are higher concentrations of the products than reactants/ the reaction favors the forward direc...
by Sabina Fridman 1D
Thu Jan 28, 2016 9:18 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: G for a system not at equilibrium
Replies: 1
Views: 343

Re: G for a system not at equilibrium

Yeah we do, Q is the reaction quotient which is the ratio of concentration (or partial pressures) of products to reactants at anytime other than equilibrium
by Sabina Fridman 1D
Thu Jan 21, 2016 4:22 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Degeneracy
Replies: 2
Views: 378

Re: Degeneracy

could somebody please explain how we would know degeneracy on its own? do we have to understand a systems entropy to understand degeneracy?
by Sabina Fridman 1D
Fri Jan 15, 2016 10:37 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Molar Heat Capacity
Replies: 6
Views: 1482

Re: Molar Heat Capacity

can somebody please clarify how we know when to use specific vs molar heat capacity?
are there certain keywords to look out for?
by Sabina Fridman 1D
Thu Jan 07, 2016 6:01 pm
Forum: Phase Changes & Related Calculations
Topic: Temperature Vs. Heat
Replies: 5
Views: 1022

Re: Temperature Vs. Heat

on this same topic, we always know that heat is either given off/absorbed if there is a difference between final and initial temperatures, right?
by Sabina Fridman 1D
Wed Nov 18, 2015 1:11 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Problem 10 in the 1st Chapter 3 Practice Quiz
Replies: 1
Views: 404

Re: Problem 10 in the 1st Chapter 3 Practice Quiz

The question is asking for the partial pressure of BrCl after the reaction reestablishes equilibrium again. The 0.54 partial pressure that you found is the new pressure of BrCl before the reaction reestablishes equilibrium. The reaction now will start off again with partial pressures of 0.54 for BrC...
by Sabina Fridman 1D
Sun Nov 15, 2015 1:51 pm
Forum: Ideal Gases
Topic: Finding the equilibrium expression K help
Replies: 4
Views: 695

Re: Finding the equilibrium expression K help

For this problem, since it didn't specify Kp or Kc are we using pressures because all the elements are gases? If not, can somebody differentiate how to know when to use Kp vs Kc other than Kc has to be used with aqueous elements?
by Sabina Fridman 1D
Mon Oct 26, 2015 1:33 pm
Forum: Hybridization
Topic: Problem 4.43
Replies: 2
Views: 518

Re: Problem 4.43

Hi, from what I understand s-character relates to how much of the hybrid orbital is made of the s-orbital like in sp hybridization, s-character is 50% and p-character is 50%, but in sp^3, s-character is 25% where p-character is 75% of the hybridization. so as bond angle increases, s-character increa...
by Sabina Fridman 1D
Thu Oct 22, 2015 11:40 am
Forum: Octet Exceptions
Topic: Chapter 3 Question 111 + Radicals
Replies: 1
Views: 358

Re: Chapter 3 Question 111 + Radicals

Hi I'm also confused about question 111 and the structures of that, but for 67b I'm pretty sure we put the radical electron on the central Cl because that allows for the lowest formal charge of 0 on each atom if we double bond both oxygens?
by Sabina Fridman 1D
Mon Oct 12, 2015 11:10 am
Forum: Trends in The Periodic Table
Topic: Ionic Radii 2.93
Replies: 3
Views: 683

Re: Ionic Radii 2.93

so it's correct that A: Cl, B: Na, C: Cl-, D: Na+ right? considering that atomic radius decreases across a period and after Na loses an electron it's e- configuration is that of Neon?
by Sabina Fridman 1D
Fri Oct 09, 2015 7:27 pm
Forum: *Particle in a Box
Topic: Problems: Particle in a box & Probability of Finding E-'s
Replies: 3
Views: 1102

Re: Problems: Particle in a box & Probability of Finding E-'

For a particle in a box will we ever have to explain the concept or simply what we know about wave functions being squared?
by Sabina Fridman 1D
Thu Oct 01, 2015 5:52 pm
Forum: DeBroglie Equation
Topic: Units for DeBroglie Equation
Replies: 4
Views: 937

Re: Units for DeBroglie Equation

isn't it because J is kg*m^2/s^2 so the units cancel out to give m for the answer?

Go to advanced search