Search found 15 matches

Tue Feb 10, 2015 10:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Re: **Important Midterm Information Winter 2015**
Replies: 6
Views: 11792

Re: **Important Midterm Information Winter 2015**

This question is in regards to Professor Lavell's Review session problems: During Professor Lavell's review session, problem number two (the camping at the sea problem) when the combustion reaction of butane was written the water was a gas. A problem similar to this in the text book, 7.105, wrote th...
Tue Feb 10, 2015 5:49 pm
Forum: General Science Questions
Topic: Combustion Reactions
Replies: 3
Views: 7134

Re: Combustion Reactions

During Professor Lavell's review session number two (the camping at the sea problem) when the combustion reaction of butane was written the water was a gas. A problem similar to this in the text book, 7.105, wrote the reaction of C6H6(L) with carbon dioxide gas and water liquid as the products. Do w...
Mon Jan 19, 2015 12:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: HW #7.47 part B
Replies: 2
Views: 351

Re: HW #7.47 part B

Hi, In the question it states that the enthalpy of combustion of gasoline can be approximated by that of octane. Since we are trying to find the yearly energy we need a value of energy when we are computing the yearly energy. In problem 7.45 it states that the enthalpy of combustion for octane is -5...
Sat Jan 17, 2015 3:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Reaction Enthalpies - #7.53
Replies: 3
Views: 529

Re: Reaction Enthalpies - #7.53

Hi, So the goal in this problem is to find the final temperature, So you need to find "q". Because the reaction take place at constant pressure, we know that "q=deltaH" You use standard formation enthalpies given in the back of the book, and the equation that finds deltaH (standa...
Sat Jan 17, 2015 3:15 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy Density and TNT
Replies: 2
Views: 628

Re: Enthalpy Density and TNT

Hi,

Are you asking about the 1/4 of TNT used in the conversion to enthalpy density (energy released per liter) for the reaction? If so, it is because there are for moles of TNT. You divide the value you got for enthalpy of the reaction by the for moles of TNT.

Hope this helps.
Thu Dec 11, 2014 12:56 am
Forum: Ionic & Covalent Bonds
Topic: FINAL EXAM 2013 Q3C
Replies: 3
Views: 670

Re: FINAL EXAM 2013 Q3C

My best suggestion is to look at how far away the elements are from each other in the periodic table, therefore looking at the electronegativity difference. Fluorine is furthest from Ag, and you also know that Fluorine is very electronegative.
Tue Dec 02, 2014 8:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Attachment of anions in the Lewis structure
Replies: 2
Views: 388

Re: Attachment of anions in the Lewis structure

You would write the anion outside of the compound within its own brackets, like in an ionic Lewis structure. If you look through chem community, I asked how to draw a specific structure, and a fellow student made an amazing video, you should check it out.
Mon Dec 01, 2014 4:23 pm
Forum: Bronsted Acids & Bases
Topic: J11 Question
Replies: 1
Views: 390

Re: J11 Question

Hi, I don't have an exact answer to your question. However, in the back of the book the answer to the first equation does not include Na. We are asked to look at the reaction of the cation or anion that is a weak acid or base. So because C6H5O^- is a weak acid and Na actually forms a strong base (Na...
Sat Nov 29, 2014 4:04 pm
Forum: Naming
Topic: Chloro vs Chlorido
Replies: 2
Views: 2185

Re: Chloro vs Chlorido

Hi chloro and chloride is essentially the same thing. Chlorido is the newer IUPAC name Convention and Chloro is the older one. Dr. Lavell said you can use either one, both are acceptable.
Sat Nov 29, 2014 4:01 pm
Forum: Naming
Topic: ch 16 #29 part b
Replies: 1
Views: 309

Re: ch 16 #29 part b

Hi, So in this problem you have to look at the oxidation states (oxidation numbers). Sulfate has a -2 charge and you know Cobalt has a +3 charge if you add those oxidation states you have +1 as the total charge of the compound. Chlorine, the anion, has a -1 charge, thus the charges of both the catio...
Sat Nov 22, 2014 12:24 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook HW problem #47b
Replies: 1
Views: 333

Re: Textbook HW problem #47b

Hi, In the problem when you look for the % of PCl5 decomposed you have your initial amount of .019M and at equilibrium its concentration is .009. So to find the amount decomposed you do .019M-.009M= .0100M. You then find the % by decomposed amount/original amount x 100% and your answer should come o...
Wed Nov 19, 2014 9:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW Ch 10 #47
Replies: 1
Views: 348

Re: HW Ch 10 #47

I cannot answer your question, but I would like to point out that if you look at the solutions manual, the value in the quadratic formula doesn't have 1.05 in front of it (the value that would get 2.1). However if you use just 2 you come to the same answer for the equilibrium mixtures.
Tue Nov 18, 2014 11:22 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Video: Drawing Coordination Compounds
Replies: 8
Views: 1389

Video: Drawing Coordination Compounds

How would we draw the following compound:
[Cr(H2O)4Cl2]Cl2.H2O
Sun Nov 09, 2014 1:46 am
Forum: Lewis Structures
Topic: Midterm Prep - Fall 2012 question 5 B. in course reader
Replies: 1
Views: 336

Re: Midterm Prep - Fall 2012 question 5 B. in course reader

Hi,
In the Lewis Structure that has a lower formal charge, carbon doesn't have a complete octet. Carbon needs to have a complete octet, therefore you use the second Lewis Structure with a triple bond.
Fri Oct 03, 2014 8:55 pm
Forum: DeBroglie Equation
Topic: wavelike properties
Replies: 1
Views: 359

wavelike properties

When using the DeBroglie equation and the wavelength found cannot be measured/detected, or wavelike properties cannot be observed, does this mean the object doesn't have wavelike properties?

Thank you