## Search found 34 matches

Mon Mar 06, 2017 3:31 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Naming organic molecules
Replies: 1
Views: 702

### Naming organic molecules

Where does he get the number thats in front of the name for example, 4-chloro-2-butanol??
Mon Mar 06, 2017 3:30 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Lewis Structure question
Replies: 1
Views: 670

### Lewis Structure question

Why does oxygen always need to have two bonds and why does carbon always needs to have 4 bonds? Can someone please explain this to me.
Thu Feb 23, 2017 11:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Class Curve
Replies: 1
Views: 403

### Class Curve

Hi does anyone know how the curve for this class works?
Thu Feb 23, 2017 10:21 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre Equilibrium
Replies: 1
Views: 297

### Pre Equilibrium

What does it mean if the slow step rate does not match the observed rate?
Wed Feb 22, 2017 8:54 pm
Forum: First Order Reactions
Topic: integral
Replies: 1
Views: 394

### integral

how does integral d[A]/[A] equal to ln[A]? does anyone know any easy way to learn integrals? Thanks
Wed Feb 22, 2017 8:41 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: overall rxn order
Replies: 1
Views: 367

### overall rxn order

on page 61 of the course reader it says that the overall rxn order = n+m=2 how did they get this number?
Wed Feb 22, 2017 4:44 pm
Forum: *Electrophiles
Topic: Chapter 4 of the book
Replies: 1
Views: 346

### Chapter 4 of the book

Where do I find the homework problems for thermodynamics and organic chem? It is not the same in the chemical principles book so idk where to find the practice problems. Does anyone know where i can find them?
Wed Feb 22, 2017 4:39 pm
Topic: intermediate
Replies: 2
Views: 426

### intermediate

what is an intermediate? and how can you figure out what are the intermediates in a reaction?
Wed Feb 22, 2017 4:37 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Activation Energy vs Free energy of activation
Replies: 3
Views: 558

### Activation Energy vs Free energy of activation

What is the difference between activation enegery and free energy of activation? and what does it mean when more molecus have E>Ea? What does E stand for?
Wed Feb 22, 2017 4:35 pm
Forum: *Electrophiles
Topic: Organic Chem and Thermodynamics
Replies: 2
Views: 422

### Organic Chem and Thermodynamics

How are thermodynamics and organic chem related? Also does kinectics control a reaction or does thermodynamics control a reaction?
Wed Feb 22, 2017 4:33 pm
Forum: *Electrophiles
Topic: Electrophiles and nucleophiles
Replies: 3
Views: 430

### Electrophiles and nucleophiles

Hi Prof Lavelle was going over this in class but did not understand it. He was making a connection of Electrophiles and Nucleaophiles to acids and bases. Can someone please explain this to me thanks.
Tue Feb 21, 2017 8:12 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8023
Views: 1407114

### Re: Post All Chemistry Jokes Here

This totally makes sense based on what we have been learning in chem.
Mon Jan 30, 2017 4:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies 8.77
Replies: 1
Views: 338

### Bond Enthalpies 8.77

Benzene is more stable and less reactive than would be predicted fro its kekule structures. use the mean bond enthalpies in table 8.6 and 8.7 to calculate the lowering in molar energy when resonance is allowed between the kekule structures of benzene.
Mon Jan 30, 2017 3:14 pm
Forum: Phase Changes & Related Calculations
Topic: Entropy vs Enthalpy
Replies: 2
Views: 451

### Entropy vs Enthalpy

Can someone please explain the difference between entropy vs enthalpy? I keep confusing the two. Also can you give an example of both and when to use them. Thanks.
Mon Jan 30, 2017 3:13 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: equation from heat to a gas
Replies: 1
Views: 362

### equation from heat to a gas

Hi what equation do we use to find heat when a gas is at constant p?
Mon Jan 30, 2017 3:11 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.57
Replies: 1
Views: 292

### 8.57

calculate the reaction enthalpy for hydrogenation of ethyne to ethane. I solved the problem and got positive 312 kj.mol-1 but the answers in the solution manual gives a -312. Can someone please explain this question to me because I do not understand the explanations that are given in the solution ma...
Mon Jan 30, 2017 12:13 pm
Forum: Phase Changes & Related Calculations
Topic: physical or phase change
Replies: 1
Views: 300

### physical or phase change

I have a question how does sublimation equal

delta H of sub= delta H of fus + delta H of vap????
Sun Jan 29, 2017 10:08 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 3
Views: 392

### Bond Enthalpies

How do you know what bond breaks and which bond is formed?
Sun Jan 29, 2017 10:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.65
Replies: 1
Views: 365

### 8.65

Hi does anyone know how to do question 65 from chapter 8? Its asks to calculate the standard enthalpy of formation of dinitrogen from the data given.
Fri Jan 13, 2017 2:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 2
Views: 295

### Enthalpy

How do I know what bonds are broken and created?
Thu Nov 17, 2016 5:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium 11.3
Replies: 1
Views: 301

### Chemical Equilibrium 11.3

How do we know when to find Partial pressure? For question 11.3 in the book it asks: Write the equilibrium expression K for each of the following reactions A. 2C2(h4)(g)+O2(g) ------> <-------- 2C2(h4)Cl2(g)=2(h2)O(g) I know that you have to get products over reactants but in the answer it has P[C2H...
Thu Nov 10, 2016 2:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: #5 Ch11
Replies: 1
Views: 307

### #5 Ch11

Depict the progress of the reaction graphically for the decomposition of PCl5 to give PCl3 and Cl2 using the values given in Example 11.8
Mon Oct 31, 2016 2:26 pm
Forum: DeBroglie Equation
Topic: 2006 MT #3
Replies: 1
Views: 393

### 2006 MT #3

for question number 3 we have to use the De Broglie equation which is wavelength=h/p but in the detailed solutions the equation is wavelength=hp^-1 why do they have the negative 1? which one is easier to use?
Thu Oct 27, 2016 5:59 pm
Forum: Dipole Moments
Topic: Charge distribution in molecules
Replies: 1
Views: 334

### Charge distribution in molecules

Can someone please explain this section. I have read the book and course reader and still do not fully understand it.
Tue Oct 25, 2016 5:37 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 1
Views: 314

### Electron Configuration

why is the electron configuration for Ag not [Kr]4d^9, 5s^2? but instead is [Kr]4d^10, 5s^1?
When should we do it like this? and also if we have the electron configuration for Cl^- should we go to the noble gas before it Ne or the answer is just [Ar]???
Wed Oct 19, 2016 9:23 pm
Forum: Ionic & Covalent Bonds
Topic: Home work question 3.39
Replies: 3
Views: 959

### Home work question 3.39

Write the complete Lewis structure for each of the following compounds: ammonium chloride; potassium phosphide; sodium hypochlorite.

Someone please help me and if you can explain step by step that would be great thanks.
Sat Oct 08, 2016 2:52 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Question 1.33 [ENDORSED]
Replies: 2
Views: 493

### Homework Question 1.33[ENDORSED]

The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 x 10^3 km s^-1. What is the wavelength of the ejected electron? No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50 x 10^16 Hz. How many much energy is required...
Sat Oct 08, 2016 2:49 pm
Replies: 5
Views: 1212

What is a black body? and how does it absorb all the frequencies?
Mon Oct 03, 2016 11:04 am
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2992

### Re: Hedrick Summit Study Group Chem 14A

Hi everyone I am glad to see that people want to make a study group that is great. Let's meet up Tomorrow October 4 7:30pm on the 7th floor west side study lounge to arrange an official meeting time and place because we have a quiz next week. If you have any questions please email me at lilahh2011@g...
Mon Oct 03, 2016 10:50 am
Forum: Administrative Questions and Class Announcements
Topic: Preparatory Self Quizzes [ENDORSED]
Replies: 3
Views: 511

### Preparatory Self Quizzes[ENDORSED]

Hi what are these self-quizzes and where can we find them? Is there a specific date we have to turn them in?
Wed Sep 28, 2016 9:45 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculations
Replies: 1
Views: 665

### Limiting Reactant Calculations

The question is from the Post-Assessment Limiting Reactant Calculations #10. How many moles of CO2(g) are produced when 500g of CaCO3(s) is used to neutralize an acid spill? the equation for the reaction at 1 atm and 25degrees C is: CaCo3(S)+H2SO4(aq)----> CaSO4(s)+CO2+H2O(l) What is 1atm and where ...
Mon Sep 26, 2016 9:05 pm
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2992

### Re: Hedrick Summit Study Group Chem 14A

My email is Lilahh2011@gmail.com. Email me so I can add you to a group chat.
Mon Sep 26, 2016 9:04 pm
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2992

### Re: Hedrick Summit Study Group Chem 14A

Yes of course that is perfectly fine. Everyone is welcomed to join (:
Sun Sep 25, 2016 10:33 pm
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2992

### Hedrick Summit Study Group Chem 14A

Who is willing to join a study group for Hedrick Summit? Reply here and we can make a group chat to set up dates and times that work best for everyone. Thanks