Pentanol Isomers Lab Report

The Increasing Enthalpy of Combustion Rates for Pentanol Isomers
EEI Report Draft - JEREMY SAJU 11B

Fuels are the main energy source of the modern world. The topic of this extended experimental investigation is to explore combustion rates of alcohols, specifically pentanol and it’s relationship with varying structural isomers. A fuel is defined as a material that stores potential energy that, when released, can be used as heat energy (Chemguide, 2003). The balanced combustion equation for pentanol is 2C5H11OH + 15O2 = 10CO2 + 12H2O (KGB, 2017). Combustion is an exothermic chemical reduction oxidation (redox) reaction occurring between a fuel and an oxidising agent (Thoughtco, 2017). An exothermic reaction is a reaction that releases energy
The general formula of alcohols is CnH2n+1OH (Wisegeek, 2017). A hydrocarbon chain is a molecule that consists of a band of carbons and one or more hydrogens bonded to each carbon whereas a hydroxyl group is a molecule composed of one hydrogen atom bonded to one oxygen atom (Sciencing, 2017, Study, 2015). Pentanol or amyl alcohol is an organic compound and alcohol of the chemical formula C5H11OH (Pubchem, 2017). Structural isomerism refers to molecules of identical molecular formula, with alternate structural arrangements. The three isomers used are 1-pentanol, 2-methylbutan-2-ol and 3-methylbutan-1-ol. The differing factor between structural isomers is mostly the number of and placement of substituents (Chemguide, 2012). A substituent is an atom or group of atoms replacing one or more hydrogen atoms, branching off the parent chain of a hydrocarbon (Chem.uiuc, 2001). Relating to substituents in alcohols, primary, secondary and tertiary alcohols possess different structured alcohols. In primary alcohols, the carbon carrying the hydroxyl group only has one alkyl group attached, in secondary alcohols the carbon with the hydroxyl group is
Pentanol has eight structural isomers, however due to shortage or unavailability, only three isomers were able to be utilised. This only contributes a narrow outlook on pentanol and it’s variance in combustion rates based on structure. In order to produce a fair scientific test, each isomer was combusted three times, allowing a more reliable result and not creating inconsistent, singular results. Precision exists within the test to a certain degree where a single higher percentage error is received on the first test and two similarly low results are received consecutively. The design of the experiment was constantly being modified and improved upon with practice tests resulting in a more refined experimental setup. Combustion rates were easily calculated through this design. The experiment’s validity to real life was quite low as pentanol is normally used as a solvent for coating CDs and DVDs. Variables were unaffected with the dependent variable being the combustion rate and the only independent variable being the isomer of pentanol. Control variables were maintained to prevent flawed results. Recommendations for improvement are to create space between the calorimeter and the heat shield to allow extinguishing of the flame and placing of the lid on time and organise and utilise more than three isomers of pentanol, providing a