Search found 7 matches

by becky a 3D
Wed Mar 08, 2017 8:16 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Describing reactions
Replies: 2
Views: 437

Re: Describing reactions

Exothermic and endothermic refer to thermodynamic properties, that is delta H. Exergonic and endergonic refer to the Gibbs free energy. We say that a negative delta H indicates an exothermic reaction, but that does not mean it is exergonic (you would have to refer to the sign of delta G) and vice ve...
by becky a 3D
Sun Feb 26, 2017 9:34 pm
Forum: *Nucleophiles
Topic: Intro to O Chem
Replies: 5
Views: 597

Intro to O Chem

will we not be doing any more readings out of the textbook for the rest of the quarter??
by becky a 3D
Wed Feb 15, 2017 3:42 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Midterm 2013 Question 3A
Replies: 4
Views: 616

Re: Midterm 2013 Question 3A

the 2259 J/g came from first converting the deltaH (vap) from kj to J. That is 40,700 J/mol. The next step is to convert from J/mol to J/g. Simply divide my molar mass of water to get final value. 40,7000/18.02= 2259 J/g
by becky a 3D
Mon Feb 13, 2017 10:48 pm
Forum: Balancing Redox Reactions
Topic: Oxidation numbers
Replies: 1
Views: 227

Oxidation numbers

In toolbox K.1, where it explains how to assign oxidation numbers, it mentions that Oxygen will usually have an oxidation number of -2 except for some exceptions, one of which is ozonides (O3-). However, in example 14.2 when writing the half rxn eq for the oxidation of Br- -> BrO3- , they use -2 for...
by becky a 3D
Sun Jan 29, 2017 11:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: When entropy=0 [ENDORSED]
Replies: 3
Views: 564

Re: When entropy=0 [ENDORSED]

a system is said to have 0 entropy when there is only 1 microstate molecules can be in, meaning all molecules are in the same energy level. The equation S= k lnW shows that entropy equals 0 when w (which represents the total # of microstates for molecules) is equal to one, that is because ln(1)=0 . ...
by becky a 3D
Tue Jan 24, 2017 9:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 576

Re: bond enthalpies

yes this was very helpful! thank you! so to my understanding, there really is no "shortcut" (i guess you could say) in identifying these bonds, as in, one would have to visualize (or physically draw out) the lewis structure of the molecule each time. which im guessing with practice and fam...
by becky a 3D
Tue Jan 24, 2017 7:56 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 576

bond enthalpies

when identifying which bonds are broken and formed in order to calculate reaction enthalpy does anyone have and tips on how to easily identify whether bonds (mainly c-c) are single double or triple?? for many im actually just visualizing the lewis structure, but for some such as CH3CHCH2, the lewis ...

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