Search found 11 matches

Tue Mar 07, 2017 11:55 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Chapter 15, Question 63
Replies: 1
Views: 425

Chapter 15, Question 63

I understand how to set up the equation with the ln k2/k1=Ea/R (1/T1 - 1/T2) equation with the information given from the problem. Which is "The rate constant of the reaction between CO2 and OH- in aqueous solution to give the HCO3- ion is 1.5 x 10^10 L/(mol)(s) at 25C. Determine the rate const...
Tue Feb 21, 2017 8:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 2 Winter 2017
Replies: 160
Views: 16804

Re: Quiz 2 Winter 2017

Can someone please explain number 7! I know it's a straight forward problem, but I must be missing a step because I can't seem to get the correct answer. So for number 7, you can use the 1st order integrated rate law, which is ln[A] = -kt + ln [A]initial and then isolate k, since you're solving for...
Tue Feb 21, 2017 6:17 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Units
Replies: 7
Views: 675

Units

For number 8 of the Practice quiz, when I calculated the answer it came out to be in seconds, but the answer provided was in minutes. Is it necessary to always convert the answer to minutes when they are asking for time. Or does it not matter if we have either seconds or minutes?
Mon Feb 13, 2017 8:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Winter 2014 Midterm Q3C
Replies: 1
Views: 299

Winter 2014 Midterm Q3C

For question 3C, why did we convert n in n deltaHvap to m(1mol/18.02g)?

I'm confused as to why they decided to change it.
Mon Feb 13, 2017 6:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Midterm Winter 2014 Q1D
Replies: 1
Views: 293

Midterm Winter 2014 Q1D

My question is regarding Question 1D for the Winter Midterm 2014 review. Where did they get the K equation from? What was the original equation? I see a very similar equation ( K= A e^-Ea/RT), but I'm confused as to how the Ea is replaced with deltaG.
Sun Feb 12, 2017 1:21 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Midterm WINTER 2013 Question
Replies: 1
Views: 348

Midterm WINTER 2013 Question

For Question 2A of the Winter 2013 Midterm in the Course Reader, I'm confused on how they obtained the equation for the heat capacity of ice. In the course reader, the solutions shows q(ice)= (n)(deltaH fusion) + m C deltaT I know where the m C deltaT came from because that is one of the equations, ...
Sun Feb 05, 2017 10:02 pm
Forum: Balancing Redox Reactions
Topic: Oxidation [ENDORSED]
Replies: 4
Views: 800

Oxidation[ENDORSED]

Is there a difference between the oxidizing and reducing agent and the species that is oxidized and reduced? I'm confused between what I think is being oxidized/reduced.
Thu Jan 26, 2017 9:13 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reaction Enthalpy
Replies: 1
Views: 329

Reaction Enthalpy

I'm currently working on chapter 8, number 47. The question asks: "For a certain reaction at constant pressure deltaH=-15kJ, and 22kJ of expansion work is done on the system. What is deltaU for this process?" I understand the concept and which equation to use, but for "w=-p deltav&quo...
Sat Jan 21, 2017 6:41 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work is done by the system.... [ENDORSED]
Replies: 1
Views: 291

Work is done by the system....[ENDORSED]

I'm working on the Chapter 8 homework problems and I just have a general question regarding work. Just for clarification: when work is done BY the system, the answer is negative and when work is done ON the system, the answer is positive? Does this always apply when the change is occurring at consta...
Sun Jan 15, 2017 10:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H subscripts
Replies: 3
Views: 1378

Re: Delta H subscripts

Will there ever be a time in which reversing the reaction will not lead to simply reversing the sign changes of all components of the equation? I don't believe so. Usually when you reverse the reaction, you have to switch the sign because for example, putting in enthalpy (endothermic) is the revers...
Sun Jan 15, 2017 10:25 pm
Forum: Administrative Questions and Class Announcements
Topic: How to find my posts
Replies: 48
Views: 47958

Re: How to find my posts

How do I create a new post? All I know is how to "Post Reply". Also, how do I change my username to include this quarter's discussion section and not the old one from last quarter in 14A? To change your username, go to the main page or any page on chemistry community, and at the top next ...