Experimental reports l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 15

Experimental Reports PowerPoint PPT Presentation


  • 61 Views
  • Uploaded on
  • Presentation posted in: General

Experimental Reports. Next week is the final week of practicals Make sure you are up to date with your reports by next week – all reports Final reports must be handed up no later than one week after completion of final practical – otherwise marks will be forfeited. Experiment 17.

Download Presentation

Experimental Reports

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Experimental reports l.jpg

Experimental Reports

  • Next week is the final week of practicals

  • Make sure you are up to date with your reports by next week – all reports

  • Final reports must be handed up no later than one week after completion of final practical – otherwise marks will be forfeited


Slide2 l.jpg

Experiment 17

Reactions of Alcohols and Carboxylic Acids


Introduction l.jpg

Introduction

  • Given samples of various alcohols and carboxylic acids

  • Establish some of their physical and chemical properties & perform various reactions


Introduction4 l.jpg

Introduction

  • You will perform solubility and acidity tests on all the compounds provided

  • Ester formation from an alcohol and carboxylic acid

  • Oxidation of an alcohol to a carboxylic acid using permanganate solution


Solubility tests l.jpg

Solubility Tests

  • To 1ml of water in three test tubes, add each of the alcohols dropwise until they cease to dissolve or until 10 drops have been added

  • Record your observations

  • Repeat with the two carboxylic acids

  • Comment on your conclusions regarding the solubilities in water


Acidity tests l.jpg

Acidity Tests

  • Use the aqueous solutions of ethanol and ethanoic acid from the solubility tests

  • Test both with blue litmus paper

  • Add 1ml of 10% NaHCO3 to each

  • Record your observations in each case


Acidity tests7 l.jpg

Acidity Tests

  • Dissolve 0.5g of sodium acetate in 5ml water – note if there is any odour

  • Add 1ml dilute H2SO4 and again note if there is any odour

  • Record your observations in each test and explain any reactions observed


Ester formation l.jpg

Ester Formation

  • Already encountered in Experiment 14

  • Heat 2ml of ethanol, 1ml ethanoic acid and a few drops of conc H2SO4 for 5 mins

  • Note any changes you observe – odour?


Ester formation mechanism l.jpg

Ester Formation - Mechanism

Include mechanism for ester formation in your report


Oxidation of phenylmethanol l.jpg

Oxidation of Phenylmethanol

  • Phenylmethanol (benzyl alcohol) can be oxidized to give benzoic acid

  • To 1ml of phenylmethanol in a conical flask add 25ml of KMnO4 solution and 0.5g of sodium carbonate

  • Heat on the water bath for 20 mins

  • Cool & acidify with conc HCl


Oxidation of phenylmethanol11 l.jpg

Oxidation of Phenylmethanol

  • Add sodium sulphite solution until the brown maganese dioxide dissolves

  • Cool to room temperature – white precipitate of benzoic acid settles out


Oxidation of phenylmethanol12 l.jpg

Oxidation of Phenylmethanol

  • Isolate crystals on the Hirsch funnel, wash with water & dry

  • Get melting point when dry

  • Calculate % yield from number of moles of phenylmethanol you began with


Calculations l.jpg

Calculations

  • Density of phenylmethanol = 1.05 gml-1

  • Use the density & volume to calculate the mass of phenylmethanol used


Calculations14 l.jpg

Calculations

  • Use the mass of phenylmethanol to calculate the number of moles

  • When dry, weigh the benzoic acid product and thus calculate the number of moles of product

  • % yield = moles benzoic acid/moles phenylmethanol


Report l.jpg

Report

  • Introduction

  • All observations from the solubility and acidity tests & reactions

  • Mechanism for ester formation

  • Weight and melting point

  • % yield of benzoic acid

  • Discussion & conclusions


  • Login