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

Comparing the Chemical Properties of Alkanes and Alkenes

Extracts from this document...


Comparing the Chemical Properties of Alkanes and Alkenes Aim To investigate and compare the chemical properties (notably the reactivity) of the alkane Cyclohexane and the alkene Cyclohexene. Hypothesis Based on previous knowledge of alkanes and alkenes I suggest the chemical properties of the two will be similar as both are fuels, however, as alkenes (but not alkanes) contain a carbon double bond (C=C) some of the chemical properties will differ. Method Apparatus: * Hard glass watch glass * Wood splints * 10 dry test tubes (two of which covered in aluminium foil) * 10 tight fitting bungs (to seal the test tubes) * Test tube rack * Bromine dissolved in an inert solvent (Bromine Water) * Acidified Potassium Manganate (VII) solution * Concentrated Sulphuric acid (H2SO4) Procedure A: Combustion 1. Place 3-4 drops of cyclohexane onto the watch glass 2. Light a splint and use this to light the cyclohexane 3. Record observations (e.g. Colour of the flame, amount of soot produced) Procedure B: Reaction with Bromine 1. Place 3-4 drops of cyclohexane into a test tube and the same again into one of the aluminium wrapped tubes. ...read more.


When kept in the dark, however, there is no apparent change to the bromine or cyclohexane. There has been no obvious reaction between the two substances and we can therefore deduce that the previous reaction is photochemical in nature. C. Acidified Potassium Manganate(VII) KMn: There was no apparent reaction, change in temperature or colour. The cyclohexane would not mix at all with the KMn and in fact seemed to settle on top of the KMn. D. Concentrated Sulphuric Acid (H2SO4): The two substances mixed but did not seem to react in any way. Having mixed they then separated to form two distinct layers. Alkene (Cyclohexene) Observations: A. Combustion: Much like the cyclohexane however the flame did seem a little smokier. B. Bromine: Whether or not in the presence of light when mixed with cyclohexene the Bromine almost instantly decolourised. C. Acidified Potassium Manganate (VII) KMn: An almost instant decolourisation followed by separation into two distinct clear layers. D. Concentrated Sulphuric Acid (H2SO4): There was an extreme exothermic reaction together with an almost instant colour change from clear to cloudy brown. ...read more.


Below is a diagrammatic representation of the structure of this molecule, which is consistent for all alkanes: Compare this to Ethene which (although having the same number of carbon atoms as ethane, cannot contain the same number of hydrogen atoms due to the presence of a carbon-carbon double bond (C=C). It is this double bond that characterises an alkene and due to the double bond the formula for alkenes is as follows: CnH2n. Where with the alkanes there was an extra two hydrogen atoms, the positions available for these hydrogen atoms have been lost as a result of the carbon atoms forming bonds with themselves. Because of this alkenes are referred to as being unsaturated. It is referred to as unsaturated because the presence of a double bond offers a site of reactivity so that other atoms can add to the molecule. The results from our tests show that the alkenes were more 'unstable' and willing to react. With the only difference between the alkane and the alkene being the presence of the double bond I can quite safely state that the reactions observed (but not necessarily combustion test) where as a result of the alkene having a double bond which offered a site of reactivity and the chemical changes to take place. ...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 Classifying Materials 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 Classifying Materials essays

  1. Aklenes and Alkanes Investigation

    Their reaction with oxygen is called a combustion reaction and it is highly exothermic. My research has come from : - Dorling Kindersley Science Encyclopedia - GCSE Key Stage 4 Science - Phillips Science and Technology - Oxford Reference English Dictionary My test will be fair because I will :-

  2. Rate of reaction of hydrochloric acid on magnesium.

    therefore the quicker the gas production will be in the specific time interval. After having done the practical work on rate of reaction I have come to realise that my prediction is correct. Evaluation: The results I received from my experiment I think are very precise because I had designed

  1. The Chemical Bond

    This sharing of electrons is as a result of the electroneagativity (electron attracting ability) of the two bonded atoms are either equal or the difference is no greater than 1.7 then the higher electronegative atom has an electron attracting ability large enough to force the transfer of electrons from the less electronegative atom.

  2. Classify and identify different polymers to determine their physical properties and uses.

    Burn each polymer separately until the experiment is completed. Some polymers have a strong, sickening smell, so it is advised that the windows be open. 5. Record the results (ie. whether it burns, melts or chars). Experiment 2 - Testing Density: 1. Fill one beaker with 200mL of water.

  1. Affect of concentration on reaction

    Conclusion I have decided the most appropriate mass of calcium carbonate to react with; highest concentration of 2 molar and lowest concentration of 0.4 molar hydrochloric acid, is 5g. The preliminary experiments have given me ideas to improve on the main experiment; calcium carbonate is ground to powder form, using

  2. To conjecture the structure and bonding of eight unknown solids by analysis of experimentally ...

    Conductive Reading Uncertainty A No N/A N/A B Yes ? 5 Amp ? 0.05Amp C No N/A N/A D No N/A N/A E No N/A N/A F No N/A N/A G No N/A N/A H Yes 1.30 Amp ?

  1. Investigation on the combustion of Alcohols.

    as you will need this data to work out the mass burnt. I will then repeat the experiment again two times so that I can get some replicated data, this then will then tell me whether I have any anomalies.

  2. Investigate the structural changes, which take place when steel is cooled at different rates ...

    is heated to 900 0C. The steel is then cooled slowly which causes only a few nuclei to form. This means the metallic crystals can grow unimpeded to a large size, which causes the metal to be more ductile and mallabel than normalised steel. This is because the carbon atoms, which are present, are distributed

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