Search found 34 matches

by Chin_Alyssa_3I
Sun Mar 19, 2017 12:53 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Winter 2016 Final Question 4 [ENDORSED]
Replies: 2
Views: 547

Re: Winter 2016 Final Question 4 [ENDORSED]

How did you know that Step 2 was the slow/rate-limiting step? Why couldn't it be step 1?
by Chin_Alyssa_3I
Fri Mar 17, 2017 5:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 214
Views: 101888

Re: Saying Thank You to Dr. Lavelle

To Dr. Lavelle, the TAs and UAs: Thank you all for your time and dedication to the class. The quality of the teaching was top-notch and all the resources outside of class from Chemistry Community, to Peer learning sessions, to office hours, has all been tremendously helpful. It has been an honor to ...
by Chin_Alyssa_3I
Tue Mar 07, 2017 10:05 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Question 15.65 Part B
Replies: 1
Views: 267

Question 15.65 Part B

From Part A, I got the equilibrium constant to be .676.

Considering the Standard change in Gibbs Free Energy formula, with a positive K and positive T then the free energy would be negative and thus the reaction would be exothermic. However the answer is endothermic. Why?
by Chin_Alyssa_3I
Tue Mar 07, 2017 9:25 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Question on Actual Quiz 2
Replies: 2
Views: 298

Question on Actual Quiz 2

I was wondering for number six on the actual quiz 2 we took in our discussion, why Step 1 was the slow step and not Step 2?
by Chin_Alyssa_3I
Sun Mar 05, 2017 7:44 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7666
Views: 1036477

Re: Post All Chemistry Jokes Here

8616638035e92edb97804630d099335e.jpg
by Chin_Alyssa_3I
Sun Feb 26, 2017 11:02 pm
Forum: Administrative Questions and Class Announcements
Topic: 2/24/17 Bruincast
Replies: 19
Views: 2156

Re: 2/24/17 Bruincast

ntyshchenko wrote:What about Lecture 2s video?


Lecture 2 does not have a video because it is not filmed. Only lecture 3 is filmed
by Chin_Alyssa_3I
Sun Feb 19, 2017 12:58 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7666
Views: 1036477

Re: Post All Chemistry Jokes Here

I want to post a joke, but all the good ones Ar (Argon)
by Chin_Alyssa_3I
Sat Feb 11, 2017 8:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Winter 2017
Replies: 87
Views: 14547

Re: Midterm Winter 2017

As I am going over past midterms in the course reader I noticed that for certain problems points are deducted for not having the correct sig figs, while for other problems, sig figs were not taken into account for the total points. I was wondering for this midterm if sig figs will be a part of our t...
by Chin_Alyssa_3I
Wed Feb 08, 2017 2:28 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Possible course reader error?
Replies: 1
Views: 305

Possible course reader error?

In class on Monday we went over page 59 in the course reader where Dr. Lavelle went over the reaction rates and derived a "formula" for us to follow when setting up the rates. In the process of the derivation, he multiply the d[O2]/dt by 2 but not for d[NO]/dt and -d[NO2]/dt. Shouldn't it ...
by Chin_Alyssa_3I
Tue Feb 07, 2017 9:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Winter 2013 Midterm Q2A
Replies: 10
Views: 782

Winter 2013 Midterm Q2A

Q: Your very particular friend Sheldon asks for a glass of exactly 400g of water at 16 C. You can get liquid water at room temperature from the faucet and ice at 0C from the freezer. How many grams of ice and how many grams of water must you combine to make Sheldon's very specific water? The only pa...
by Chin_Alyssa_3I
Sun Feb 05, 2017 6:58 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy
Replies: 8
Views: 810

Re: Enthalpy

How do you know when to use Kelvin or Celsius in a problem? Can you just always use and convert a question to Kelvin? How you know which unit to use is really dependent on the rest of the values in your problem and their units. Use the other values and units as a guide to help you determine whether...
by Chin_Alyssa_3I
Fri Jan 27, 2017 9:17 am
Forum: Student Social/Study Group
Topic: Review?
Replies: 4
Views: 573

Re: Review?

what do we use the green course reader for? I do not understand the difference between the torquoise and the green course readers we received from the course reader store. I believe that the green course reader starts covering organic chemistry, which I believe we will start to go over later in the...
by Chin_Alyssa_3I
Fri Jan 20, 2017 2:36 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Ch 8.85
Replies: 1
Views: 461

Ch 8.85

8.85 The oxidation of nitrogen in the hot exhaust of jet engines and automobiles occurs by the reaction N2 (g) + O2 (g) -> 2 NO(g)   H°=180.6 kJ (a) How much heat is absorbed in the formation of 1.55 mol NO? (b) How much heat is absorbed in the oxidation of 5.45 L of nitrogen measured at 1.00 atm an...
by Chin_Alyssa_3I
Fri Jan 20, 2017 1:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Kekulé structure?
Replies: 1
Views: 230

Kekulé structure?

What is the Kekulé structure that is referred to in problem 77 of chapter 8?
by Chin_Alyssa_3I
Fri Jan 13, 2017 6:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.65
Replies: 3
Views: 273

Problem 8.65

8.65 Calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data, 2 NO(g) + O2 (g) -> 2NO2(g)  H°= -114.1 kJ 4 NO2(g) + O2(g) -> 2 N2O5(g) H°= -110.2 kJ and from the standard enthalpy of formation of nitric oxide, NO (see Appendix 2A). At first I approached it using ...
by Chin_Alyssa_3I
Fri Dec 02, 2016 11:24 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7666
Views: 1036477

Re: Post All Chemistry Jokes Here

Why do chemists learn about ammonia first?

...


Cause it's pretty basic stuff
by Chin_Alyssa_3I
Sun Nov 27, 2016 6:16 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig figs in calculations for pH and pOH
Replies: 2
Views: 315

Sig figs in calculations for pH and pOH

This is a general question for when calculating. Do we still take into account sig figs when we give our final answer? As I do the textbook problems and compare the answers, I noticed that the answers in the textbook for pH and pOH are always rounded off to 2 decimal places regardless of the sig fig...
by Chin_Alyssa_3I
Sun Nov 27, 2016 3:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Problem 11. 87
Replies: 1
Views: 276

Problem 11. 87

11.87 Dissociation of a diatomic molecule, X2(g) -> 2 X(g) occurs at 500 K. Picture 1 shows the equilibrium state of the dissociation and picture 2 shows the equilibrium state in the same container after a change has occurred. Which of the following changes will produce the change shown? (a) Increas...
by Chin_Alyssa_3I
Tue Nov 22, 2016 3:37 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 11.73 b
Replies: 1
Views: 300

11.73 b

11.73 State whether reactants or products will be favored by an increase in the total pressure (resulting from compression) on each of the following equilibria. If there is no change, explain why that is so. (b) H2O(g) + C(s) ↔ H2(g) + CO(g) Since there are 2 moles on both sides, I thought that ther...
by Chin_Alyssa_3I
Thu Nov 17, 2016 2:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming Question and Coord. # for Nitrito
Replies: 3
Views: 395

Re: Naming Question and Coord. # for Nitrito

Thank you for your reply! However in the course reader on page 117 there is an asterisk next to nitrito and the asterisk indicates which ligands are polydentates, as stated on the bottom of the diagram...So is that an error...?
by Chin_Alyssa_3I
Thu Nov 17, 2016 1:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming Question and Coord. # for Nitrito
Replies: 3
Views: 395

Naming Question and Coord. # for Nitrito

I know that when you go from FORMULA to the NAME, the ligands must be in alphabetical order. However when you go from NAME to FORMULA, I noticed the metal comes first but is there a particular order for the ligands? Also I know that nitrito is a polydentate but specifically is it a bidentate? (Coord...
by Chin_Alyssa_3I
Wed Nov 09, 2016 12:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14A Midterm Fall 2016 Rooms & Review Sessions
Replies: 16
Views: 7662

Re: Chem 14A Midterm Fall 2016 Rooms & Review Sessions

In class Professor Lavelle mentioned that the detailed solutions were posted online. However I couldn't hear what he said afterwards so I was wondering if he stated exactly where. I can't seem to find it on Chem Community or the Class website.
by Chin_Alyssa_3I
Tue Nov 01, 2016 11:35 am
Forum: Administrative Questions and Class Announcements
Topic: Chem 14A Midterm Fall 2016 Rooms & Review Sessions
Replies: 16
Views: 7662

Re: Chem 14A Midterm Fall 2016 Rooms & Review Sessions

I noticed that sometimes the constant values given in our notes/course reader does not exactly match the laminated periodic table we received with the course reader. For example, h=6.626E-34 in our reader but is more specifically stated as h=6.62608E-34 on the periodic table Also c=3.00E8 vs c=2.997...
by Chin_Alyssa_3I
Mon Oct 31, 2016 10:10 am
Forum: Hybridization
Topic: sp^2 Hybridization
Replies: 1
Views: 254

sp^2 Hybridization

I was wondering for the sp^2 hybridization if there is always an unhybridize p orbital that forms a pi bond or is that just the case for the Carbon atom because of its potential double bonds. How about for B? Would B have an unhybridize p orbital? How would you know or solve for the difference?
by Chin_Alyssa_3I
Fri Oct 28, 2016 9:32 am
Forum: Administrative Questions and Class Announcements
Topic: Chem 14A Midterm Fall 2016 Rooms & Review Sessions
Replies: 16
Views: 7662

Re: Chem 14A Midterm Fall 2016 Rooms & Review Sessions

I have a lecture right before this midterm so I will not have time to go back to the hill to drop off my backpack, my phone, and all my books. May I bring my backpack into the testing room and leave it in the front and/or with the test proctor? If not, is there anywhere else I can store my stuff?
by Chin_Alyssa_3I
Wed Oct 26, 2016 2:40 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7666
Views: 1036477

Re: Post All Chemistry Jokes Here

CATions

An ion with a PAWS-itive charge
by Chin_Alyssa_3I
Wed Oct 19, 2016 2:01 pm
Forum: Electronegativity
Topic: Calculating EN Difference [ENDORSED]
Replies: 1
Views: 327

Calculating EN Difference [ENDORSED]

So let's say you want to calculate the Electronegativity Difference of CH4... ( C = 2.6 ; H = 2.2 )

Would the answer just be .4 or do you have to multiply 2.2 by 4 since there are 4 H atoms and then subtract by 2.6?
by Chin_Alyssa_3I
Tue Oct 11, 2016 10:17 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Quiz 1 Fall 2015 #3 [ENDORSED]
Replies: 3
Views: 480

Quiz 1 Fall 2015 #3 [ENDORSED]

Find the uncertainty in the position of a marble of bass 1.5 g given that its speed is known to within plus or minus .55 m/s

My question is whether the uncertainty in velocity is .55 or is it the difference...(.55 - -.55 = 1.10)?
by Chin_Alyssa_3I
Tue Oct 04, 2016 11:35 am
Forum: Properties of Electrons
Topic: 1.15....Where did I go wrong? [ENDORSED]
Replies: 3
Views: 733

1.15....Where did I go wrong? [ENDORSED]

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. [sol] Since it is a Lyman series, I know that nf (n final) is 1. I al...
by Chin_Alyssa_3I
Mon Oct 03, 2016 12:01 am
Forum: Properties of Electrons
Topic: Atomic Spectra Post Assessment Question
Replies: 3
Views: 537

Re: Atomic Spectra Post Assessment Question

Where did you get 1 meter from?
by Chin_Alyssa_3I
Tue Sep 27, 2016 9:27 pm
Forum: Limiting Reactant Calculations
Topic: Fundamentals M.5 Part B
Replies: 2
Views: 525

Re: Fundamentals M.5 Part B

Thank you so much!
by Chin_Alyssa_3I
Tue Sep 27, 2016 11:50 am
Forum: Limiting Reactant Calculations
Topic: Fundamentals M.5 Part B
Replies: 2
Views: 525

Fundamentals M.5 Part B

M.5 Solve this exercise without using a calculator. The reaction 6 ClO2 + 2BrF3 -> 6ClO2F + Br2 is carried out with 12 mol ClO2 and 5 mol BrF3. (b) Estimate how many moles of each product will be produced and how many moles of the excess reactant will remain.
by Chin_Alyssa_3I
Mon Sep 26, 2016 2:45 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G5
Replies: 6
Views: 1076

Re: Fundamentals G5

Okay make sense. So with that in mind then for part b, since for 1 mol of Na2CO3 there is only 1 mol CO32-, you would just divide the mol with .08 M, correct?
by Chin_Alyssa_3I
Mon Sep 26, 2016 2:31 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G5
Replies: 6
Views: 1076

Fundamentals G5

G.5 A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric fl ask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a fl ask to obtain (a) 2.15 mmol Na+; (b) 4.98...

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