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

An Experiment To Identify A Series Of Liquids

Extracts from this document...


BACKGROUND THEORY ALKENES The alkene in this set of liquids is cyclohexene. It has the structural formula of CH2CHCHCH2CH2CH2. It has an intense, sharp smell. The test for alkenes is the addition of bromine water. In the event of an alkene being present, the bromine water, which is normally an orange-brown colour, will decolourise to leave a clear halogenoalkane. In this case, the halogenoalkane formed will be 1,2 - dibromocyclohexane. The reaction is electrophilic addition or in this case, halogenation. Equation: CH2CHCHCH2CH2CH2 + Br2 ==> CH2CHBrCHBrCH2CH2CH2 Cyclohexene bromine 1,2 - dibromocyclohexene HALOGENOALKANES Bromoethane is the halogenoalkane in the set of liquids given. It is also known as ethyl bromide, and has an ether-like smell. Its structural formula is CH2CH2Br. The test for halogenoalkanes is to add aqueous sodium hydroxide, then warm with ethanolic silver nitrate solution. If there is a halogenoalkane present, a precipitate of silver bromide will be formed. In the case of bromide ions, a cream precipitate will form; chloride ions form a white precipitate, and iodide ions form a yellow precipitate. ...read more.


Its structural formula is CH3COOH. The test for carboxylic acids is to add sodium bicarbonate solution. If a carboxylic acid is present, the solution will effervesce or fizz. The gas given off is carbon dioxide. Water is also formed, and the remaining compound is sodium acetate. The reaction is decomposition, and is reversible. Equation: CH3COOH + NaHCO3(alc) ==> CH3COONa + CO2 + H2O Ethanoic acid sodium bicarbonate sodium acetate carbon dioxide water WATER Water is the other chemical in this test. Its chemical formula is H2O. The test for water is to add anhydrous copper (II) sulphate solution. This solution is white, but after adding it to water, the solution will turn blue. The solution is now pentahydrate copper (II) sulphate, or chalcanthite. The reaction is hydration. Equation: 5H2O + CuSO4(l) ==> CuSO4.5H2O Water anhydrous copper (II) sulphate pentahydrate copper (II) sulphate METHOD * Place a few cm3 of each liquid into a separate test tube, labelling each with the appropriate letter label from the bottle. * Place the test tubes in the test tube holder * Add approximately 3cm3 of bromine solution, which will be orange-brown, to each test tube. ...read more.


o Rinse out the other test tubes and add the relevant chemicals to the three remaining tubes again. * Add approximately 3cm3 of anhydrous copper (II) sulphate to each test tube. o If the solution turns from white to blue, there is water present. The solution now contains pentahydrate copper (II) sulphate. o Rinse out the other test tubes and add the relevant chemicals to the two remaining tubes again. * Heat water in the kettle and pour into water bath if necessary * Add approximately 3cm3 of acidified potassium dichromate to each test tube, and warm in water bath. o If the solution turns from orange to green, there must be butan-1-ol, as this only occurs with primary or secondary alcohols; butan-1-ol is a primary alcohol. The other alcohol, methylpropan-2-ol is a tertiary alcohol, and so will not undergo a colour change. o Rinse out the remaining test tube and add the relevant chemical. * Add propanoic acid to the remaining test tube o The solution will remain colourless, but give off a sweet smell. This means that an ester is formed. This esterification is the confirmation of an alcohol, and means that methylpropan-2-ol must be present if the previous oxidation reaction did not occur. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous 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 GCSE Aqueous Chemistry essays

  1. Investigating the Effects of Increasing Copper Sulphate Solution Concentrations on the Germination of Cress ...

    This is when the pH change causes the tertiary structure of the enzyme to lose its shape, with the ionic bonds breaking up. When the active site loses its shape from this and from a loss of charge in the amino acids, the enzyme is said to be denatured and no longer functions, or forms enzyme substrate complexes.

  2. Titration with a primary standard.

    0.08 g Balance (2 decimal place) 0.008 g Balance (3 decimal place) 0.0008 g Measuring Cylinder (25 cm3) 0.5 cm3 Graduated Pipette (25 cm3, Grade B) 0.04 cm3 Burette (50 cm3, Grade B) 0.08 cm3 Volumetric Flask (250 cm3, Grade B)

  1. Obtain pure samples of Ethanol (CH3CH2OH) and Ethanoic Acid (CH3COOH) from fermented Yeast (Saccharomyces ...

    The processes, which take place in bioreactors, are referred to as fermentation. The term fermentation originally applied only to anaerobic processes but is now used broadly to include all the processes whether aerobic or anaerobic. The contents of most fermenters are stirred during operation, but this is not always the

  2. Reactivity Series Investigation

    measure hydrocholic acid which is 15cm3 and after we measured it we are going to put it into a conical flask.Repeat the measuring of the hydrocholic acid and putting it into the conical flask till all the 5 conical flasks have 15cm3 of hydrocholic acid.Then get the clamp stand and

  1. Electronic spectroscopy - Homoleptic chromium(III) complexes and the spectrochemical series.

    1.25g of the purple crystal was obtained. Given that the RMM of CrCl3�6H2O = 266.4g mol-1 and the RMM of [Cr(acac)3] = 349.2g mol-1, 1.30g/266.4g mol-1 = 4.88x10-3mol, so 1.70g of product is expected and this represents a percentage yield of 74%. The complex [Cr(NH3)6]Cl3 was prepared as follows.

  2. Hydrolysis of Halogenoalkanes.

    Then add 1cm3 of Sodium hydroxide to each test tube, and then heat in water bath to around 50�C. Check with thermometer. 6.) Then record the time taken for each precipitate to form for each Halogenoalkane. Using the stop clock Table of reactions Halogenoalkane Visual Result 1-chlorobutane I predict

  1. Comparing the solubility's of copper sulphate, sodium chloride and potassium nitrate.

    Copper Sulphate - A salt soluble in water and methanol. Blue crystals. (CuSO4 SH2O) White colour when hydrated. May irritate skin, eyes, nose and throat. May affect liver if inhaled or swallowed. 2. Sodium Chloride - Common rock salt. (NaCl)

  2. We are investigating which alcohol is the most effective for producing heat and energy. ...

    The beaker should be copper each time. Fair test- to ensure that this is a fair experiment all of these variables should be the same for each experiment. Predictions- Ethanol: H H 2*CO2 H C C OH 3*H2O H H Propan 1-ol: H H H H 3*CO2 H C C

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