[runnerup]

Hello, This is my first time posting something here. I think I will be here for a while as I may need help with chemistry. This is my first lab and I was wondering if I am typing it correctly.

Thank you,

Chemistry 40          
Separation of a Mixture                  January 26th 2005

Purpose:
? To separate a solid mixture of naphthalene C10H8, common table salt (NaCl) and sand (SiO2)
Procedure:
   ? Heat the mixture to sublime the naphthalene.
   ? Dissolve the salt in water to extract it.
   ? Filter the mixture to separate.
   ? Evaporate the water to recover the salt and the sand.
Materials:
Naphthalene C10H8, common table salt (NaCl) and sand (SiO2) mixture, ice,  beakers (3), evaporating dish, wire gauze with an iron ring and ring stand assembly, Bunsen burner, filter paper, rubber policeman, boiling chips, and a glass rod.
Data:
1.   Mass of beaker 1                  69.420g
2.   Mass of beaker 1 & mixture               71.425g
      Mass of mixture               2.005g
3.   Mass of beaker 1 & solid after sublimation         71.354g
      Mass of naphthalene(s)            0.071g
4.   Mass of beaker 2                  62.825g
5.   Mass of beaker 2 & NaCl(s)               63.857g
      Mass of NaCl(s)               1.012g
6.   Mass of beaker 3                  63.907g
7.   Mass of beaker 3 & sand               64.717g
      Mass of sand                  .81g

Calculations:
1.   Mass of the solids recovered               1.893g
2.   Percentage yield = (mass of solids recovered/mass of recovered mixture) x 100
   1.893 / 2.005 = 0.94413965 x 100 = 94.41396509
   94.41%
3.   Mass % of naphthalene =
   0.071 / 1.893 = 0.037506603 x 100 = 3.750660328
   3.751%
4.   Mass % of NaCl =
   1.012 / 1.893 = 0.534601162 x 100 = 53.46011622
   53.46%
5.   Mass % of sand =
   .81 / 1.893 = 0.427892234 x 100 = 42.78922345
   42.79%

[Donaldson Tan]

how is naphthalene collected?

[Mitch]

sublimation

[savoy7]

It depends on the format that your prof, teacher, business, journal, etc., prefers.

Some suggestions, are:
You have covered all of the technical aspects of the lab, but how did one know to filter the sand?  One had to have the "background knowledge"  to order to determine the protocol.  Background knowledge is all that you know going into the lab.  If I was doing a lab to determine what type of metal a cylinder is composed of and using density & specific heat to determine it,  my background knowledge would be density and specific heat(the definitions and equations for example).  In your lab, it's your knowledge on mixtures.  What have you learned in class about mixtures?  What have you learned from your textbook?

This "background knowledge" is how scientists become educated on a subject (by reading journal articles, etc).  With this they can develop an hypothesis (educated guess - here's that educated word again) and determine how they can test it (an experiment).

After one goes through the methodology (procedure) and collects data (results), are they done?  Science uses this experimental process to expand knowledge on a subject.  They explain this usually in a conclusion and discussion section.

I would suggest just a conclusion section.  A good conclusion might include:  Immediately answer the obj or purpose.  Defend your answer (how do you know it is correct?).  State the chemistry that happened - refers back to the "background knowledge" section.  Errors or limitations - state what went wrong with the lab or any errors that are innate in the lab.  Finally, maybe recommend some improvements to the lab or maybe a new lab or question.

Those 2 sections would go into your lab like this:
Purpose/objective
Background Knowledge
Procedure/method
Results/data
Calculations
Conclusion

that would be a pretty complete lab.  I read the abstract of labs to determine if the information can help me.  I read the method if I'm looking for an assay (technique).  I read the conclusion and discussion sections to gain knowledge on the subject.

Here are some websites from different places that have lab formats.  Note: some are biological in format, but still can be used.

http://www.wisc.edu/writetest/Handbook/ScienceReport.html
http://www.hamilton.edu/academic/Resource/WC/bio_lab.html
http://www.mhhe.com/biosci/genbio/maderinquiry/writing.html

I hope this helps.
savoy out

[runnerup]

Yes savoy this help alot. Thank you for your reply. I will be sure to add those 2 sections to my lab and thanks again for the sites you posted in the thread. I have book marked them all.  

Thank you,

Christian

[runnerup]

Yes savoy this help alot. Thank you for your reply. I will be sure to add those 2 sections to my lab and thanks again for the sites you posted in the thread. I have book marked them all.  

Thank you,

Christian

[runnerup]

Yes savoy this help alot. Thank you for your reply. I will be sure to add those 2 sections to my lab and thanks again for the sites you posted in the thread. I have book marked them all.  

Thank you,

Christian