• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

To Identify Bio chemicals in an unknown substance

Extracts from this document...

Introduction

To Identify Bio chemicals in an unknown substance Introduction The object of the experiment is to test a substance and identify the bio chemicals, which exist in that substance. Food tests are used to identify which bio chemicals exist in a substance. The substances characterised are in the tests are: carbohydrates, starch, lipids and peptide bonds. Method: The following tests were used to identify the relevant substances: Benedicts Test Carbohydrates - reducing sugars such as glucose fructose and maltose * Add 2cm3 of a solution to a test tube. * Add an equal volume of Benedicts solution. ...read more.

Middle

if above test is positive Starch Test Starch * Add 2cm3 1% solution to a test tube * Add a few drops of I2/KI solution. A blue-black colouration indicates starch present To Identify Bio chemicals in an unknown substance Method Lipids Test Lipids such as oils, fats and waxes. * Add 2cm3 of absolute ethanol to a test tube * Add 2cm3 of solution to the test tube * Dissolve the solution by shaking vigorously * Add an equal volume of cold water A cloudy white suspension indicates lipids are present Biuret Test Add 2cm3 of solution to a test tube Add an equal volume of 5% potassium hydroxide solution and mix Add 2 drops of 1% copper ...read more.

Conclusion

The Ph turned red indicating a Ph of 1. Sufficient sodium hydroxide was added until the litmus paper turned olive green indicating a neutralised solution. The Benedict's test was carried out on the neutralised solution. The solution turned orangey red after heating, indicating a positive result. Starch test After the I2/KI solution was added there was no change to the substance it did not have a blue-black colouration indicating a negative result. To Identify Bio chemicals in an unknown substance Results Lipid test After dissolving the solution in ethanol a cloudy white suspension did not form, indicating a negative result. Biuret test After adding potassium hydroxide and copper sulphate no colour developed indicating a negative result. Conclusion The unknown substance is a protein containing both reducing and non-reducing sugars. 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Physical Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Physical Chemistry essays

  1. Marked by a teacher

    Experiment investigating hydrogen bonding in different chemicals.

    5 star(s)

    The same steps in part C were repeated using same volume of ethyl ethanoate but 20cm3 and 30cm3 of trichloromethane respectively. 2. The same steps in part C were repeated using same volume of trichloromethane but 20cm3 and 30cm3 of ethyl ethanoate respectively.

  2. Identification of an Organic Unknown

    blue/green therefore it would be near neutral although it will turn pink/red if a functional group of either carboxylic acid or phenol is present as they are acidic. After this experiment I will have two functional groups that I would not have identified as I have identified the alcohol.

  1. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    I also used burettes as opposed to measuring cylinders to measure out volumes of reactants, which gives a lower percentage error than a measuring cylinder would have. However, it is possible that my method led to errors. These procedural errors are discussed below (4.2, page 47).

  2. Test for reducing sugars (Benedict's Test)

    A reducing sugar is a sugar with reducing properties. When a reducing sugar is heated with Benedict's oslution, the blue copper (II) sulphate (soluble)is reduced to form a brick-red ppt of copper (I) oxide (insoluble). DO NOT OVERHEAT your mixture after the appearance of the red ppt 'cos it will turn dark brown then black ...

  1. Structure and function of lipids in plants and animals

    with the tails from both layers "inside" (facing toward each other) and the heads facing "out" (toward the watery environment) on both surfaces. (See diagram below.) The fact that the layer is dynamic (fluid), i.e. it can move sideways and exchange places in their own row, means that the membrane can shut itself if it is punctured.

  2. Identify an unknown substance through a series of tests that should systematically eliminate all ...

    539 New Understanding of Chemistry For Advanced Level. Carboxylic acids. The carboxylic acid consists of a C=O bond, where the carbon is also attached to an OH group. The evolution of carbon dioxide from sodium hydrogen carbonate is used as a test to distinguish carboxylic acids from weaker acids such as phenols.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work