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Aim: To investigate the substances given off at different temperatures from crude oil (petroleum) mixture.
* Fractional Distillation glassware and thermometer
* Clamp stand x 2
* Conical flask
* Supply of cold water
* Rubber tubes x 2
* Test tube rack
* Small glass test tubes x 5
* Rubber stopper x 5
* Evaporating basin
* Micro Bunsen Burner and bench mat
* Wooden Splint
* Boiling stones
* Crude Oil supply
1. Set up the clamps stands and the fractionating glassware as shown in the diagram.
2. Connect the rubber tubes to the two open tubes of the condenser.
3. Connect the other end of the rubber tubing to a water tap and let the other one flow into a basin. Turn on the tap.
4. Place two boiling stones into the conical flask and then pour in the crude oil into the flask. Place the flask right above the micro-burner as shown in the diagram.
5. Heat the crude oil mixture slowly. Record at which temperature one of the compounds in the mixture evaporate, and then collect it in the small test tube after it passes through the condenser.
6. Repeat step 5 until maximum temperature has been reached and/or no more compounds evaporate.
7. Test the compounds which were collected. Light them in an evaporating basin and record the time it takes to run out.
Data Table of Results of Hydrocarbons tested
Boiling Point Range (ï¿½C)
36 – 40
Very Low Viscosity
66 – 69
90 – 94
Very slightly cloudy
Brownish – black
These results prove to us that firstly, crude oil being a mixture of several hydrocarbons, that the mixture provided was a simulation. Secondly, there are noticeable trends in the hydrocarbons. As the molecules gets heavier and heavier, by which I mean that we go from pentane to Hexane and so on, the viscosity of the compound increases, as well as the time taken for it to burn up completely. The boiling point also increases.
These hydrocarbons belong to the first organic homologous series: Alkanes. Alkane molecules are completely saturated and each carbon atom has at least 2 hydrogen atoms attached to it. Apart from the two end carbon atoms, the other ones are attached to two other carbon atoms each. A covalent bond between a carbon atom and a hydrogen atom is strong, and a bond between two carbon atoms is also strong. It therefore takes a lot of energy to overcome this bond, and hence a higher temperature and more time is needed to break these compounds apart. The more carbon atoms an alkane possesses, the more energy is needed to break it apart. This explains the increasing boiling points, and is also one of the main reasons why hydrocarbons are used as fuels.
Kerosene was the only one of the four hydrocarbons which could not be heated to its boiling point and hence the temperature recorded is the one that was given to us. It did, however, last the longest when it was burned. Therefore that result coincides with the one that was given to us. Its other properties which could be verified have given us further proof of the fact that its temperature is higher than the other hydrocarbons’.
Also related to the viscosity, the weight of each hydrocarbon also increased as the viscosity increased. By the time kerosene was being handled, a really wide margin of difference could be felt from pentane.
The equipment available was not enough to determine the boiling point of Kerosene
Get a macro burner and heat the kerosene to its boiling point
The difference in viscosity between the first two hydrocarbons was hard to tell
Measure the poise of the two compounds and record the difference
The evaporating basin in which the hydrocarbons were heated was the same all throughout
Use a different evaporating basin for each compounds so that the heat from the previous test does not affect the next test
The main mixture provided to us was not actual crude oil, simply a simulated substitute
To gather all of the compounds found in crude oil use a mixture which contains all of them kind of obvious