Understanding Equations for Chemistry Exam Prep

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Discussion Overview

The discussion revolves around two equations related to concentration and moles in chemistry, specifically in the context of preparing for a chemistry exam. Participants seek clarification on the derivation and application of these equations.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on the two equations, expressing urgency due to an upcoming exam.
  • Another participant interprets the equations, suggesting that the "%" symbol in the equations may indicate division, while also correcting the placement of terms in the first equation.
  • A participant questions the ambiguity of the original query, asking for more specific details regarding the concepts in question.
  • There is a discussion about the derivation of the equations, with one participant explaining that the second equation is derived from the definition of molar concentration and includes a conversion factor.
  • Another participant introduces the concept of equation triangles as a method for visualizing relationships between variables, emphasizing the need for volume to be in dm³.
  • A later reply critiques the use of equation triangles, suggesting that a better understanding of algebra is preferable to relying on memorization of specific methods.

Areas of Agreement / Disagreement

Participants express differing views on the clarity of the original question and the appropriateness of using equation triangles versus algebraic methods. There is no consensus on the best approach to understanding the equations.

Contextual Notes

Some participants note the ambiguity in the original question and the potential confusion regarding the use of the "%" symbol in the equations. There is also a mention of the importance of unit conversions, particularly between dm³ and cm³.

Who May Find This Useful

This discussion may be useful for students preparing for chemistry exams, particularly those seeking to understand the relationships between concentration, volume, and moles, as well as different methods for solving related problems.

hamxa7
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can someone clear my concepts about these two equations ?

Equation 1... Concentration(g/dm3) = Concentration (Mol/Dm3) % Mass Of 1 Mole Of Solute

Equation 2... Number Of Moles Of Solute=Concentration(Mol/Dm3) x Volume In Cm3 % 1000cm3

reply quickly.. got my chem school exam tommorow...
 
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Hard to tell what you want to clear not knowing what your concepts are.

I guess by % in the second equation you mean division, although the same % in the first equation is placed where the multiplication should be:

[tex]C [\frac {g} {dm^3}] = C [\frac {mol}{dm^3}] \times M_m [\frac {g} {mol}][/tex]

where Mm is a molar mass.

So, what is your problem (apart from procrastination)?
 
I wanted to know how are they are evolved...
Answering a problem regarding the equations woud be appreciated...
 
You have to be more specific, at the moment I have no idea what you are interested in - you question is ambiguous and way too vague.

By evolved - do you mean derived? If so, the second is just a a molar concentration definition solved for n, and with a mL <-> L conversion factor added. First can be obtained combining definition of molar concentration and definition of molar mass.
 
1dm3=1000cm3. The 1000 is just a conversion factor. Equation triangles helped a lot with me. (But volume has to be in dm3)
...^
.../mol\
/vol*conc\
You use an equation triangle by covering up the quantity you want to work out. That leaves an equation to work it out using the other two.
Also:
...^
../mass\
/mol*Mr\
and
...^
.../vol\
/mol*24\
 
Last edited:
jetwaterluffy said:
Equation triangles

Bastardized way of dealing with equations when you don't know basic algebra. It is really much better to learn general method of solving the equation for an unknown, than to memorize particular approach to particular problem.
 

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