Experiment 1 1 20g10mL14g 143 mL is the minimum amount of ethanol needed to

Experiment 1 1 20g10ml14g 143 ml is the minimum

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calculate for the mass of methylene chloride in 38 drops. Experiment 1: 1. (2.0g*(10mL))/1.4g= 14.3 mL is the minimum amount of ethanol needed to recrystallize 2.0g sample of compound X (14.3mL* 0.21g)/10mL= 0.3g of compound X will remain dissolved in the cold solvent. 2. It is necessary to use only a minimal amount of hot solvent because excess of solvent will prevent recrystallization. The excess solvent will keep the compound partially dissolved, preventing crystallization. 3. If a preheated filter is not used during the gravity filtration step, the compound will start to recrystallize on the filter paper itself. This will hinder the separation of the pure compound from impurities. 4. Benzyl alcohol is not a good choice for recrystallization for fluorenol because the boiling point of Benzyl alcohol is 205 °C, which is more than the melting point of fluorenone. This will cause the liquid fluorenone to separate from the alcohol when the solution cools, preventing recrystallization, thus making it a poor choice of solvent. 5. A. Sand can be removed using the regular gravity filtration B. Colored organic contaminants can be removed using activated charcoal when boiling the solution and then by performing gravity filtration
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C. A very soluble contaminant can be removed when they form crystals using gravity filtration. 6. Acetone is a useful cleaning solvent because it is very polar and can dissolve almost any molecule. It would not be a good recrystallization solvent because it will keep the compounds dissolved, preventing crystallization of the compound. Acetone is extremely flammable, so it can cause a fire in the lab if not used carefully.
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  • Fall '13
  • JeramyBaum

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