Search found 32 matches

by Alexandra Carpenter 1G
Sat Mar 17, 2018 7:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic vs. Voltaic
Replies: 2
Views: 199

Galvanic vs. Voltaic

What is the difference between a galvanic cell and a voltaic cell? Are both spontaneous and therefore have a positive standard E?
by Alexandra Carpenter 1G
Fri Mar 16, 2018 1:46 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Monatomic vs. Diatomic
Replies: 2
Views: 456

Monatomic vs. Diatomic

In the Winter 2011 Midterm, #2B, it states that a monatomic gas, A has a larger number of particles than B, a diatomic gas. Can someone explain why a monatomic gas has more particles?
by Alexandra Carpenter 1G
Fri Mar 16, 2018 1:16 am
Forum: Administrative Questions and Class Announcements
Topic: Organic Chemistry
Replies: 1
Views: 191

Organic Chemistry

Will we have to know organic chem to the extent of what is on the practice final?
by Alexandra Carpenter 1G
Wed Mar 14, 2018 12:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow steps and intermediates
Replies: 2
Views: 91

Slow steps and intermediates

It is coincidental that in the problem we did in class on mechanism, the slow step was the one that contained the intermediate molecule both times correct? In other words, having the intermediate in the rate does not make that step the slow step?
by Alexandra Carpenter 1G
Wed Mar 14, 2018 12:35 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Step
Replies: 4
Views: 176

Slow Step

Just to be clear, if a mechanism has two steps, can the first one be the slow step and the second one be treated at equilibrium?
by Alexandra Carpenter 1G
Sun Mar 11, 2018 10:31 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: k and Ea
Replies: 4
Views: 243

k and Ea

Why does the k of a reaction go down when the activation energy goes up?
by Alexandra Carpenter 1G
Wed Mar 07, 2018 10:12 pm
Forum: Second Order Reactions
Topic: Second Order
Replies: 3
Views: 272

Second Order

There is a problem in a workbook that asks, "Consider the reaction, A + B --> C + D, with rate = k[A]^2. True or false, the time it takes [A] to decrease from 1.0 to 0.50 M is the same as the time it takes for [A] to decrease from 0.50 to 0.25 M.

Why is this false?
by Alexandra Carpenter 1G
Mon Mar 05, 2018 11:59 pm
Forum: General Rate Laws
Topic: 15.17
Replies: 3
Views: 143

15.17

The question includes 3 reactant, where A is first order, B is second order, and C is zero order. Part b asks you to write the rate law for the reaction. The answer doesn't include the concentration of C, but if we did in an answer, would it be marked wrong?
by Alexandra Carpenter 1G
Sun Mar 04, 2018 9:39 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanism
Replies: 2
Views: 110

Reaction Mechanism

What is the definition of the reaction mechanism?
by Alexandra Carpenter 1G
Thu Mar 01, 2018 9:52 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order of the Reaction [ENDORSED]
Replies: 3
Views: 141

Order of the Reaction [ENDORSED]

Is there a way to determine n just given the reaction? Or would they have to tell us in the problem.
by Alexandra Carpenter 1G
Mon Feb 26, 2018 10:19 pm
Forum: General Rate Laws
Topic: 15.3/Unique Rate
Replies: 2
Views: 115

15.3/Unique Rate

In the problem, the reaction is given as N2(g) --> 3 H2(g) + 2 NH3(g). The unique rate if reaction is half of the rate of reaction for NO2. When finding this, do we divide by the coefficient of the reactant only?
by Alexandra Carpenter 1G
Wed Feb 21, 2018 11:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidizing and Reducing Agents
Replies: 2
Views: 131

Oxidizing and Reducing Agents

A worksheet asks, "Arrange the following species from greatest to least strength as an oxidizing agent: Li(s), Na(s), Ag(s), Fe^3+(aq).
How do we tell the difference, especially in transition metals?
by Alexandra Carpenter 1G
Wed Feb 21, 2018 10:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Conducting Metal
Replies: 1
Views: 87

Conducting Metal

In the case of adding Pt(s) to the end of a cell diagram, how do we know if the metals in the redox reaction are conductive?
by Alexandra Carpenter 1G
Tue Feb 20, 2018 11:53 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.35
Replies: 3
Views: 184

14.35

The question asks "Determine the equilibrium constants for the following reactions: (a) Mn(s) Ti2 (aq) --> Mn2 (aq) Ti(s)
In this question, if lnK = -35 (2 sig figs), why is the K value only 1 sig fig (6 x 10^-16)?
by Alexandra Carpenter 1G
Tue Feb 13, 2018 2:42 pm
Forum: Balancing Redox Reactions
Topic: 14.1 Question
Replies: 2
Views: 134

Re: 14.1 Question

In a half reaction, by just writing out the oxidation that occurs, it may not be balanced. Hydrogen ions are used to balance any excess hydrogens on the other side of the reaction, while adding water molecules does the same for balancing oxygens. So we don't know for sure from the beginning that any...
by Alexandra Carpenter 1G
Tue Feb 13, 2018 2:37 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 3/2R vs. 5/2R
Replies: 1
Views: 307

Re: 3/2R vs. 5/2R

3/2R is used to calculate the heat capacity, Cv,m, of a gas that is at constant volume. 5/2R is used to calculate the heat capacity, Cp,m, of a gas at constant pressure.
by Alexandra Carpenter 1G
Mon Feb 12, 2018 11:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework
Replies: 1
Views: 124

Homework

Just making sure, there is homework due this week in discussion right?
by Alexandra Carpenter 1G
Wed Feb 07, 2018 11:42 pm
Forum: Balancing Redox Reactions
Topic: 14.11 [ENDORSED]
Replies: 1
Views: 96

14.11 [ENDORSED]

The question states, "Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells". Do we have to calculate E for this question? I didn't think we did but the solution manual does it.
by Alexandra Carpenter 1G
Tue Feb 06, 2018 5:50 pm
Forum: Balancing Redox Reactions
Topic: Basic vs. Acidic
Replies: 6
Views: 177

Basic vs. Acidic

What is affected when a reaction takes place in a basic or acidic solution?
by Alexandra Carpenter 1G
Mon Feb 05, 2018 1:39 pm
Forum: Balancing Redox Reactions
Topic: 14.3
Replies: 3
Views: 95

14.3

In class we learned that if something was oxidized, that means it lost an electron, causing the oxidation number to increase. In 14.3 part a, the equation reads as: Cl2 (g) + S2O32- (aq) → Cl- (aq) + SO42-
If the chlorine ion is going from an oxidation state of 0 to -1, why is it being oxidized?
by Alexandra Carpenter 1G
Sun Feb 04, 2018 9:48 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Trouton's Law
Replies: 1
Views: 108

Trouton's Law

Do we have to know about the explanation of Trouton's Law?
by Alexandra Carpenter 1G
Thu Feb 01, 2018 10:21 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Third Law
Replies: 3
Views: 187

Third Law

Is the basis of the Third Law of Thermodynamics that perfect crystals have an entropy of 0 as the temperature reaches 0K? Or is there more to it? Thank you!
by Alexandra Carpenter 1G
Wed Jan 31, 2018 1:52 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Class Example
Replies: 6
Views: 183

Class Example

In class, we went over a problem where we needed to calculate the temperature needed to make the reaction spontaneous. I understand that delta G needs to be negative for the reaction to be considered as such. We got 333K by setting the delta G to 0, but would that be the final answer? Or would the a...
by Alexandra Carpenter 1G
Sun Jan 28, 2018 4:23 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy vs. Degeneracy [ENDORSED]
Replies: 5
Views: 208

Entropy vs. Degeneracy [ENDORSED]

In my notes, the definitions for entropy and degeneracy seem similar, so what is the difference between the two?
by Alexandra Carpenter 1G
Mon Jan 22, 2018 7:11 pm
Forum: Phase Changes & Related Calculations
Topic: 8.41
Replies: 1
Views: 85

8.41

The question states, "A 50.0-g ice cube at 0.0 C is added to a glass containing 400.0 g of water at 45.0 C. What is the nal temperature of the system (see Tables 8.2 and 8.3)? Assume that no heat is lost to the surroundings." The heat of the ice cube is 1.67 x 10^4 J + (209 J/degrees C)(Tf...
by Alexandra Carpenter 1G
Mon Jan 22, 2018 12:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework Week 3
Replies: 1
Views: 115

Homework Week 3

Will the homework questions we turn in this week be from Chapter 9?
by Alexandra Carpenter 1G
Thu Jan 18, 2018 12:11 pm
Forum: Phase Changes & Related Calculations
Topic: 8.39
Replies: 2
Views: 121

8.39

In this problem, we use the equation Qfusion = mCfusion. Where in the textbook does it discuss this formula or where does it come from? I can't seem to find it.
by Alexandra Carpenter 1G
Wed Jan 17, 2018 9:01 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity of Gases
Replies: 2
Views: 99

Heat Capacity of Gases

What do the equations Cv,m = 3/2R and Cp,m represent or calculate? And when would we use them?
by Alexandra Carpenter 1G
Wed Jan 17, 2018 1:34 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Energy Change in an Isolated System
Replies: 4
Views: 166

Energy Change in an Isolated System

Since there is no matter or energy transfer from an isolated system to its surroundings, there is no way to change the internal energy of an isolated system correct?
by Alexandra Carpenter 1G
Sun Jan 14, 2018 8:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Discussion Calorimetry Question
Replies: 1
Views: 107

Discussion Calorimetry Question

In my discussion, we went over a problem that asked this, "There is 4.51 g of NaOH in 100mL of H2O at 19.5 degrees C. NaOH dissolves and the temp of H2O rises to 31.7 degrees C. Determine the delta H of the NaOH solution. When we worked out the problem, we didn't use the 4.51 grams of NaOH in o...
by Alexandra Carpenter 1G
Wed Jan 10, 2018 7:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Notation
Replies: 4
Views: 180

Notation

In problem #9b for Chapter 8, "The internal energy of a system increased by 982 J when it absorbed 492 J of heat. (a) Was work done by or on the system? (b) How much work was done?", is there a specific reason the answer is in scientific notation, instead of just 490 J? Or is it just a pre...
by Alexandra Carpenter 1G
Wed Jan 10, 2018 2:56 pm
Forum: Phase Changes & Related Calculations
Topic: Energy and Phase Changes
Replies: 5
Views: 248

Energy and Phase Changes

In lecture today, we went over the heating curve of water. Why does the vaporization transition (40.7 kJ/mol) require much more energy than the melting transition (6.01 kJ/mol)?

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