Search found 26 matches

by Ryan Distaso 3C
Sat Mar 12, 2016 12:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing Cell Diagrams
Replies: 1
Views: 347

Writing Cell Diagrams

When writing cell diagrams, when is it necessary to write a comma between two molecules in an anode or cathode instead of drawing a single line between them? And when is it necessary to include a catalyst like platinum in the cell diagram?
by Ryan Distaso 3C
Wed Mar 09, 2016 8:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.67
Replies: 2
Views: 413

Homework 8.67

In part a of this question, bonds formed are positive and bonds broken are negative when calculating the enthalpy change. In part b of this question, bonds broken are positive and bonds formed are negative. This is what I had believed was correct. Why is part a calculated differently?
by Ryan Distaso 3C
Wed Mar 09, 2016 8:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.67b
Replies: 1
Views: 376

Homework 8.67b

This asks to find the enthalpy of formation of CH3OH in the liquid state. Next to the C atom to be atomized is a symbol, gr. What does this mean?
by Ryan Distaso 3C
Mon Mar 07, 2016 8:31 pm
Forum: *Alcohols
Topic: Tert-Butanol
Replies: 1
Views: 378

Tert-Butanol

Why is the common name of 2-Methyl-2-propanol tert-butanol when it appears that the OH is connected to a secondary atom?
by Ryan Distaso 3C
Tue Mar 01, 2016 5:32 pm
Forum: *Electrophilic Addition
Topic: # of Intermediates in Electrophilic Addition
Replies: 1
Views: 333

# of Intermediates in Electrophilic Addition

This is a very basic question but just to be certain, in a two step electrophilic addition reaction there will be one intermediate formed, correct?
by Ryan Distaso 3C
Tue Mar 01, 2016 5:14 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Quiz 3 Preparation
Replies: 2
Views: 414

Re: Quiz 3 Preparation

The fourth and fifth solutions are different Geometric Isomers because they have different geometries around the double bond. The fourth solution is "cis" while the fifth solution is "trans," based on their respective orientations. This does affect their properties and those are...
by Ryan Distaso 3C
Tue Mar 01, 2016 5:06 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Quiz 3 Preparation
Replies: 2
Views: 414

Quiz 3 Preparation

Question 3 of the second practice quiz asks to draw 5 constitutional isomers of C4H8. In the attached picture, what is the difference between the fourth and fifth solutions? Is the fourth solution structurally different because it is a half ring or is it just another way of drawing the fifth solution?
by Ryan Distaso 3C
Tue Mar 01, 2016 3:38 pm
Forum: *Electrophilic Addition
Topic: Organic Textbook 4.28
Replies: 1
Views: 302

Organic Textbook 4.28

"Write the full reaction mechanism for the electrophilic addition reaction of hydrogen bromide, HBr, to propene, CH3CHCH2, producing 2-bromopropane, CH3CHBRCH3. Draw the transition states." Why is it that the H in HBR bonds specifically to the C bonded to two H? Why couldn't it bind to the...
by Ryan Distaso 3C
Tue Mar 01, 2016 3:33 pm
Forum: *Electrophilic Addition
Topic: Organic Textbook 4.25
Replies: 1
Views: 295

Organic Textbook 4.25

The answer for this problem shows one Br molecule in Br2 pulling on the electron of another, making one partial positive and one partial negative. As this is the same atom, why does one pull harder than the other?
by Ryan Distaso 3C
Tue Mar 01, 2016 3:25 pm
Forum: General Rate Laws
Topic: Rate limiting step
Replies: 1
Views: 296

Rate limiting step

What is the involvement of the rate limiting step in writing the overall rate law of a reaction? Are the reactants used in the rate limiting step the only ones that are supposed to be used in the overall rate law?
by Ryan Distaso 3C
Mon Feb 29, 2016 8:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3 Winter 2016
Replies: 48
Views: 19387

Re: Quiz 3 Winter 2016

For Quiz 2, the formula sheet did not exactly match up with the one that comes with the course reader. The integrated rate laws were not explicitly labelled as being for first order, second order, and zero order and it seemed like we were somewhat expected to have them memorized. Will this be the ca...
by Ryan Distaso 3C
Tue Feb 16, 2016 4:14 pm
Forum: Administrative Questions and Class Announcements
Topic: Up to what problem should we work in the textbook?
Replies: 4
Views: 562

Re: Up to what problem should we work in the textbook?

Chem_Mod wrote:You should complete the whole prep quiz 2. The workbook is due at the end of Friday lecture.


Thank you. However my question was more specifically about what problem we should work up to in the textbook, not the workbook.
by Ryan Distaso 3C
Tue Feb 16, 2016 3:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Up to what problem should we work in the textbook?
Replies: 4
Views: 562

Re: Up to what problem should we work in the textbook?

I stopped at question 15.65 because the questions started to talk about catalysis which we haven't covered yet. What about questions like 15.11 which deals with temperature and reaction rate? Maybe I am mistaken but this seems to be covered on page 76 of the course reader, which is not covered by Q...
by Ryan Distaso 3C
Tue Feb 16, 2016 3:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Up to what problem should we work in the textbook?
Replies: 4
Views: 562

Up to what problem should we work in the textbook?

I am asking because Quiz 2 only covers up to 15.10 and page 75 in the course reader.
by Ryan Distaso 3C
Mon Feb 08, 2016 4:48 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework 9.69
Replies: 1
Views: 344

Homework 9.69

Where are the standard Gibbs free energies for compounds like NADH and NAD being obtained for this problem?
by Ryan Distaso 3C
Sat Feb 06, 2016 9:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Voltage/Potential Difference
Replies: 1
Views: 432

Voltage/Potential Difference

High voltage electrical systems are often discussed as being very dangerous. What about the high potential difference in an electrical system makes it especially dangerous to come in contact with? Is it that the high tendency of the reaction to occur means a large amount of electricity is flowing at...
by Ryan Distaso 3C
Tue Jan 26, 2016 5:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Differing formulas
Replies: 1
Views: 286

Differing formulas

Why is the formula for change in entropy with differing temperature given in the book as nRln(T2/T1) when it is listed on this forum and in the constants sheet as nCln(T2/T1)?
by Ryan Distaso 3C
Sun Jan 24, 2016 2:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework 8.67d
Replies: 2
Views: 366

Homework 8.67d

This question asks to find the enthalpy of formation of benzene (C6H6) with and without resonance. How is resonance determined and how does it change the solving of this problem?
by Ryan Distaso 3C
Sun Jan 24, 2016 11:33 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.53
Replies: 1
Views: 394

Homework 8.53

This question asks, The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113 C to 22.799 C. The calorimeter assembly is known to have a total heat capa...
by Ryan Distaso 3C
Fri Jan 22, 2016 9:13 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: What is meant by spontaneous reaction?
Replies: 1
Views: 334

What is meant by spontaneous reaction?

In today's lecture mention was made that for certain sets of conditions, a reaction can occur spontaneously. Does this just mean that it will occur without work being done to the system?
by Ryan Distaso 3C
Mon Jan 11, 2016 2:14 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework 8.31
Replies: 4
Views: 597

Homework 8.31

This question asks, "Find the heat released by 5.025 g of Kr(g) at0.400 atm as it cools from 97.6 C to 25.0 C at (a) constant pressure and (b) constant volume. Assume that krypton behaves as an ideal gas." In the solution to this problem, the molar heat capacity is not calculated but is ...
by Ryan Distaso 3C
Sun Jan 10, 2016 2:47 pm
Forum: Phase Changes & Related Calculations
Topic: Melting/Evaporation vs Vaporization
Replies: 4
Views: 876

Melting/Evaporation vs Vaporization

When a substance goes from a solid to a gas by vaporization, does it go through the process of melting and then evaporate or does it go directly to a gas?
-Ryan Distaso, Discussion 3E
by Ryan Distaso 3C
Fri Nov 27, 2015 4:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant Equation Walkthrough Video
Replies: 1
Views: 316

Equilibrium Constant Equation Walkthrough Video

https://www.youtube.com/watch?v=IiwctdqpGZ0"onclick="window.open(this.href);return false; This video runs through a sample problem for finding the equilibrium constant for a reaction at equilibrium. IMPORTANT CORRECTION ON THE MATH: in the video I plugged in 0.1908M as the concentration of carbon di...
by Ryan Distaso 3C
Sun Oct 11, 2015 5:18 pm
Forum: Limiting Reactant Calculations
Topic: Quiz 1 Preparation #2
Replies: 1
Views: 1684

Quiz 1 Preparation #2

This question asks, given this reaction: 2Al(s) + 6HCl(aq) = 2AlCl3(aq)+3H2(g) If you had 5.43g of aluminum and 7.8g of hydrogen chloride, how many grams of AlCl3 would you get? Converting these masses to moles gives .201mol Al and .213mol HCl. As there must be 3mol HCl per mole of aluminum, HCl is ...
by Ryan Distaso 3C
Sun Oct 11, 2015 4:30 pm
Forum: General Science Questions
Topic: High ionization energy cations
Replies: 1
Views: 628

High ionization energy cations

In lecture the other day it was mentioned that it is extremely difficult to remove electrons from elements with very high ionization energies. Is it impossible for these elements to form cations outside of a laboratory setting? If it happens, what are the natural processes with enough energy to caus...
by Ryan Distaso 3C
Sun Oct 11, 2015 4:24 pm
Forum: Molarity, Solutions, Dilutions
Topic: Quiz 1 Preparation #1
Replies: 1
Views: 397

Quiz 1 Preparation #1

The second part of this question asks how many millimeters of a 2.00M solution would need to be added to obtain 250mL of a 0.650M solution. Could this question be solved with a ratio and if not, why not? It seems to me that concentration of matter in liquid should change proportionally according to ...

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