What is a Sphere Equation? Help with Chemistry Problem

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Discussion Overview

The discussion revolves around the concept of a "sphere equation" in the context of a chemistry homework problem involving the complete combustion of ethane. Participants explore what a sphere equation might entail, particularly in relation to visual representations of molecular structures.

Discussion Character

  • Homework-related
  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about the term "sphere equation" and its absence in their textbook or lectures.
  • Some participants suggest that a sphere equation may refer to drawing atoms as spheres, similar to a ball and stick model, but without the sticks.
  • Another participant proposes that the term could relate to space-filling models of molecules.
  • A later reply introduces the concept of a Newman Diagram, stating it represents the conformational arrangement of atoms but does not apply to reactions.
  • One participant mentions the possibility of using a hard-sphere interaction model to write an equation of state, though this is deemed unrelated to the homework question.
  • Another participant shares links to resources about hard sphere equations and the Carnahan-Starling equation, suggesting these might be relevant to the discussion.
  • One participant clarifies that the course is designed for non-science majors, indicating a desire to minimize the complexity of the chemistry involved.
  • Participants discuss the simplicity of Newman Diagrams and share links to examples, with one expressing newfound curiosity about them.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the meaning of "sphere equation." While some propose visual representations using spheres, others challenge the existence of such a term in chemistry, leading to multiple competing views.

Contextual Notes

The discussion highlights the ambiguity surrounding the term "sphere equation" and its potential interpretations, including visual models and mathematical equations. There is a lack of clarity regarding the specific requirements of the homework problem.

Math Is Hard
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OK, I'm clueless. I have this one homework problem where I am asked to represent a reaction with a "sphere equation". I have no idea what this is and I can't locate it in my book. Wasn't mentioned during lecture either.
Does anyone know what this means? :confused:

Here's the whole problem (maybe it will make sense in context):

a) write a chemical equation for the complete combustion of ethane.
b) represent this equation with Lewis structures.
c) represent this reaction with a sphere equation.
 
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I think they are asking you to draw a picture of the reaction using spheres to represent the atoms of each molecule.
 
Tide said:
I think they are asking you to draw a picture of the reaction using spheres to represent the atoms of each molecule.
hey Tide - thanks for responding. Do you mean kinda like a ball and stick diagram?
 
Yes - but without the sticks!
 
Use x^2 + y^2 + z^2 = c to define the boundaries of spherical surfaces.
 
OK, it seems all she was looking for was a "ball and stick" drawing for each molecule in the reaction, but my space filling representations were acceptable. Darn chemistry! Too much artwork!
 
Math Is Hard said:
OK, I'm clueless. I have this one homework problem where I am asked to represent a reaction with a "sphere equation". I have no idea what this is and I can't locate it in my book. Wasn't mentioned during lecture either.
Does anyone know what this means? :confused:
Here's the whole problem (maybe it will make sense in context):
a) write a chemical equation for the complete combustion of ethane.
b) represent this equation with Lewis structures.
c) represent this reaction with a sphere equation.
MIH : What you want is called a Newman Diagram or Newman representation. That only tells you the conformational arrangement of atoms in a molecule (like ethane), but can not represent a reaction.

There's no such thing in chemistry as a sphere equation for a chemical reaction. At best, you can write an equation of state based on a hard-sphere interaction model, but that has nothing to do with this question.
 
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Description of hard sphere equation.

http://www.math.rutgers.edu/~lebowitz/PUBLIST/jll.pub_43.pdf


It would appear that one is to represent the equation of state as:

p/[itex]\rho[/itex]kT = a([itex]\rho[/itex]) + b([itex]\rho[/itex])/kT + c([itex]\rho[/itex])/(kt)2 + . . .

or see if this looks familiar

http://www.zae-bayern.de/ectp/abstracts/maeso1.html

Have you seen the Carnahan-Starling equation yet?

This might be a question for Gokul.
 
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  • #10
ahh yes.. Newman Diagrams..
http://www.sollicitatiegesprek.nl/newman.jpg
Never heard of 'em!
umm.. before you guys get too carried away, I should tell you this is a class for NON-science majors. :redface: I am lazy as hell, and want to do the LEAST amount of chemistry possible. Here's the description:
Designed for non-science majors, this course examines the concept of the submicroscopic world of chemistry, ranging from protons to proteins in subject matter. Prerequisite: Beginning and Intermediate Algebra for College Students or two years of high school algebra.
And the book is from our friends at The American Chemical Society.
http://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=education%5Ccurriculum%5Ccontext.html"
 
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  • #11
Math Is Hard said:
ahh yes.. Newman Diagrams..
http://www.sollicitatiegesprek.nl/newman.jpg
That's the one !

Newman diagrams are very simple things with a fancy name. It's one of the first things you learn in organic chemistry.

Here's what one looks like :

http://www.chem.tamu.edu/organic/Spring2004/Review/Image382.gif
 
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  • #12
hmm.. y'know Gokul, that doesn't look quite as scary as I imagined. I was curious about it, so I found some explanations of the diagrams here:
http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch03/ch3-diagrams.html
so if I understood what they said correctly, that intersection in the front (of the diagram you posted) represents one carbon atom, and it has CH3, Br, and H attached to it. Then the circle would be another carbon atom (behind it) that the front one is bonded to, and it has CH3 and two H atoms attached to it.
http://www.chem.tamu.edu/organic/Spring2004/Review/Image382.gif
So it's kind of like a perspective drawing?
 
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  • #13
Yup. That's all it is !
 

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