Is My Compound Pure Despite Low Percent Recovery?

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SUMMARY

The discussion centers on the purity assessment of a recrystallized unknown carboxylic acid, where a narrow melting point range suggested purity, yet a low percent recovery (< 40%) indicated significant impurities. The key formula for percent recovery is identified as (mass of pure compound)/(mass of impure compound) x 100%. The conflicting results highlight the importance of understanding both melting point analysis and percent recovery in evaluating compound purity.

PREREQUISITES
  • Understanding of melting point determination
  • Knowledge of percent recovery calculation
  • Familiarity with recrystallization techniques
  • Basic concepts of carboxylic acid properties
NEXT STEPS
  • Research the principles of recrystallization for purifying compounds
  • Learn about the significance of melting point ranges in purity assessment
  • Explore methods to improve percent recovery in crystallization processes
  • Investigate the differences between percent yield and percent recovery
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Chemistry students, laboratory technicians, and researchers involved in organic synthesis and compound purification processes.

yungwun22
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Homework Statement


I recrystallized an unknown carboxylic acid, then found the melting point of the dried compound and identified it. The melting point range was narrow and that said to me that the compound was pure, but the percent recovery was very low (< 40 %). Indicating there was still a significant amount of impurities. I just wanted to know how to resolve these conflicting results and/or which contribution is the most important in determining purity. Forgive me if this question is stupid.



Homework Equations





The Attempt at a Solution

 
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yungwun22 said:

Homework Statement


I recrystallized an unknown carboxylic acid, then found the melting point of the dried compound and identified it. The melting point range was narrow and that said to me that the compound was pure, but the percent recovery was very low (< 40 %). Indicating there was still a significant amount of impurities. I just wanted to know how to resolve these conflicting results and/or which contribution is the most important in determining purity. Forgive me if this question is stupid.



Homework Equations





The Attempt at a Solution



By the " recovery " do you mean ( experimental yield / theoretical yield ) x 100 %?
 
No, the percent recovery. (mass of pure compound)/(mass of impure compound) x 100 %. I'd only heard of percent yield before this class, but this formula is what was given. Only to be used in purification processes.
 

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