Search found 36 matches
- Sat Mar 17, 2018 12:37 am
- Forum: Experimental Details
- Topic: Rate law in multiple step reactions [ENDORSED]
- Replies: 3
- Views: 1091
Rate law in multiple step reactions [ENDORSED]
How are we supposed to differentiate the cases in which the overall rate law is equal to the rate law of the slow step vs when it is not?
- Sat Mar 17, 2018 12:23 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Bomb Calorimeter
- Replies: 6
- Views: 865
Re: Bomb Calorimeter
A bomb calorimeter is like a regular a calorimeter except a bomb calorimeter is an isolated system which is sealed and thus provides constant pressure and volume.
- Sat Mar 17, 2018 12:18 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Transition States
- Replies: 1
- Views: 241
Transition States
What will we have to know about transition state theory for the final?
- Sat Mar 17, 2018 12:14 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 14.17
- Replies: 2
- Views: 330
Re: 14.17
(a) Write balanced half-reactions for the redox reaction of an acidified solution of potassium permanganate and iron(III) chloride.
(b) Write the balanced equation for the cell reaction and devise a galvanic cell to study the reaction (write its cell diagram).
(b) Write the balanced equation for the cell reaction and devise a galvanic cell to study the reaction (write its cell diagram).
- Sat Mar 17, 2018 12:11 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.57
- Replies: 2
- Views: 466
Re: 8.57
Why does the fact that the chemical equation is a combustion reaction mean that you do reactants - products instead of the other way around? I thought the only time you do reactants minus products is when you are dealing with bond enthalpies.
- Sat Mar 17, 2018 12:08 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Test 2 Question 8 wording
- Replies: 3
- Views: 510
Re: Test 2 Question 8 wording
The two half reactions given are:
Ag + I- ----> AgI + e- (anode) = -0.15 V
AgCl +e- ---> Ag + Cl- (cathode) = +0.22 V
Ag + I- ----> AgI + e- (anode) = -0.15 V
AgCl +e- ---> Ag + Cl- (cathode) = +0.22 V
- Fri Mar 16, 2018 11:52 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: flipping half reactions
- Replies: 2
- Views: 531
Re: flipping half reactions
Because we usually assume that the overall E(cell) value should be favorable, meaning the value is positive, you would want to flip the equation that has the smaller (or more negative) E(cell) value and make that the anode.
- Fri Mar 16, 2018 11:48 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.57
- Replies: 2
- Views: 466
8.57
My first intuition in solving this problem is to do enthalpy of products minus the enthalpy of reactants, and I get the correct number when I solve it this way only the sign is wrong ( + instead of -). The book solves this by coming up with a bunch of intermediary reactions that add up to the final ...
- Fri Mar 16, 2018 11:40 pm
- Forum: Student Social/Study Group
- Topic: what to study for the final
- Replies: 1
- Views: 513
what to study for the final
Is there anything that isn't covered in our listed homework that we should review for the final?
- Fri Mar 16, 2018 11:34 pm
- Forum: General Rate Laws
- Topic: Test 3 #5
- Replies: 1
- Views: 328
Re: Test 3 #5
First you need to solve for the molarities of NO and O2. You are given the weight in grams of each so you divide by their respective molar masses to get moles of each compound then you divide each by .75L to make the values a concentration in molarity. You would then plug in these values you have in...
- Fri Mar 16, 2018 11:29 pm
- Forum: *Carboxylic Acids
- Topic: Functional Groups
- Replies: 5
- Views: 2484
Re: Functional Groups
I don't think we will necessarily have to know how to draw the functional groups, but we will probably need to be able to identify them in a given structure.
- Fri Mar 16, 2018 11:26 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Test 2 Question 8 wording
- Replies: 3
- Views: 510
Test 2 Question 8 wording
In question 8 it says that the following half-reactions are unbalanced, but their charges and the moles of each atom are equal on either side, so how are they unbalanced?
- Fri Mar 16, 2018 11:22 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2 Question 8
- Replies: 1
- Views: 351
Test 2 Question 8
For part c of this problem when you calculate the E(cell) value, I know it's usually cathode minus anode, but that is when you are working with two reduction potential. In the problem you are given an oxidation potential and a reduction potential, so I added the two together (0.22+ (-)0.15)= 0.07 bu...
- Fri Mar 16, 2018 11:13 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9.13
- Replies: 2
- Views: 482
9.13
In this question I understand that you can use delta S=nRln(V2/V1) for the first part of the problem, but how are you supposed to know to use S=nRln(T2/T1) instead of delta S=nCln(T2/T1) with the C-value calculated for constant volume?
- Fri Mar 16, 2018 11:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Derivations
- Replies: 2
- Views: 439
Derivations
Which equations will we need to know how to derive for the final?
- Mon Feb 26, 2018 1:53 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 14.7 part (c) [ENDORSED]
- Replies: 1
- Views: 298
14.7 part (c) [ENDORSED]
Can someone explain why it is okay for calculate the Q value by combining the pressures and molarities and just canceling out their units. Isn't there some type of conversion that has to be done? Shouldn't the values used to calculate Q be in the same units?
- Mon Feb 26, 2018 1:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 14.17
- Replies: 2
- Views: 330
14.17
Could someone walk me through this problem? I'm not sure how to set it up or how you're supposed to know which half reactions to write from the information given.
- Mon Feb 26, 2018 1:42 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 14.37 part a
- Replies: 2
- Views: 343
14.37 part a
When calculating the cell potential of the cell given in part (a) why are you allowed to omit Cl as is shown in the solutions manual?
- Wed Feb 21, 2018 4:25 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Solution Manual 14.9 [ENDORSED]
- Replies: 1
- Views: 262
Solution Manual 14.9 [ENDORSED]
Why are the answers for parts a and b both in J/mol? Shouldn't the answer just be in Joules of kilojoules?
- Wed Feb 21, 2018 2:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cell vs. Daniell Cell [ENDORSED]
- Replies: 1
- Views: 216
Galvanic Cell vs. Daniell Cell [ENDORSED]
What is the difference between a Galvanic Cell and a Daniell Cell? Is there any difference in how you solve problems if it is a Daniell cell vs. a normal Galvanic cell?
- Thu Feb 15, 2018 5:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 14.9
- Replies: 2
- Views: 355
14.9
In homework problem 14.9 how are you supposed to determine the n value?
- Sat Feb 10, 2018 6:04 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.13 Gibbs free energy of formation
- Replies: 1
- Views: 223
9.13 Gibbs free energy of formation
In the last paragraph on page 353, it says " A thermodynamically stable compound is a compound with a negative standard Gibbs free energy of formation. A thermodynamically unstable compound is a compound with a positive standard Gibbs free energy of formation." Why is this so if when delta...
- Wed Jan 31, 2018 11:49 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2764324
Re: Post All Chemistry Jokes Here
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- Wed Jan 31, 2018 11:47 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: Gas atoms
- Replies: 4
- Views: 484
Re: Gas atoms
A real life example of this that might help you understand this would be spraying perfume in the corner of a room. It is "spontaneous" for the scent molecules to disperse throughout the room rather than to stay only in the corner. It is a lot like the diffusion of water across a membrane i...
- Wed Jan 31, 2018 11:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy in a Vacuum [ENDORSED]
- Replies: 5
- Views: 929
Re: Internal Energy in a Vacuum [ENDORSED]
I think that the idea of a vacuum is that there is no pressure in the system, thus the energy change is zero because in the equation w=-p(delta)t the value for p is always zero, so q=0 as well.
- Wed Jan 31, 2018 11:34 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: ideal cooler [ENDORSED]
- Replies: 5
- Views: 582
Re: ideal cooler [ENDORSED]
I agree, I think that the idea with this and the inclusion of the word "ideal" alludes to the fact that this "cooler" works very well, such that the system can be acknowledged as isolated.
- Wed Jan 31, 2018 11:32 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Midterm
- Replies: 6
- Views: 710
Midterm
Will the Midterm be a cumulative test over chapter 8 and 9? If so will the questions be more conceptual like on test one or will they be more problem solving based problems like in the homework?
- Wed Jan 31, 2018 11:20 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Standard State
- Replies: 2
- Views: 309
Standard State
Are we supposed to memorize the standard states of certain compounds or is there a way to determine this which can be applied to all?
- Wed Jan 31, 2018 11:15 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat Capacity
- Replies: 3
- Views: 431
Heat Capacity
If for example there is a problem about dropping a metal at one temperature into a cup with water at a different temperature are we to assume that at equilibrium the final temperature of the metal is equal to the temperature of the water?
- Wed Jan 31, 2018 11:10 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2764324
Re: Post All Chemistry Jokes Here
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- Wed Jan 24, 2018 11:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: HW 8.1
- Replies: 3
- Views: 468
HW 8.1
Can someone explain how gasoline burning in an automobile engine is an open system, because to me it seems that it should be closed because the gas combusts within the engine which is in my mind a closed space.
- Wed Jan 24, 2018 11:07 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calculating heat (q)
- Replies: 4
- Views: 2105
Calculating heat (q)
How do you know when to use q=mc(delta)T vs when to use q=nc(delta)T?
- Wed Jan 24, 2018 11:02 pm
- Forum: Phase Changes & Related Calculations
- Topic: Calculating the Change in Enthalpy
- Replies: 4
- Views: 617
Calculating the Change in Enthalpy
How do you calculate the change in enthalpy of a phase change?
- Wed Jan 24, 2018 10:56 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2764324
Re: Post All Chemistry Jokes Here
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- Fri Jan 19, 2018 11:41 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter vs. Bomb Calorimeter
- Replies: 2
- Views: 288
Calorimeter vs. Bomb Calorimeter
What is the difference between these two types of calorimeters? How is it reflected when calculating how much heat is released from any given reaction?
- Fri Jan 19, 2018 11:28 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2764324