To Investigate Whether There is a Link Between the Number of Carbon Atoms in Alcohol and its Standard Enthalpy of Combustion

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To Investigate Whether There is a Link Between the Number of Carbon Atoms in Alcohol and its Standard Enthalpy of Combustion


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Introduction

Alcohol is the common family name for the hydrocarbon group Alkanols. The generic formula of these organic compounds is:

Cn.H(2n+1).OH

The first example from the alkanol family is:

Methanol - C.H3.OH

From the generic formula we can see that different types of alcohols will have different number of carbon atoms.

 

In this project I intend to investigate whether there is a link between the number of carbon atoms in alcohol and its standard enthalpy of combustion ΔH.

Planning

Different members of the alcohol family have different numbers of carbon atoms and should therefore have different enthalpy ΔH values.  The complete combustion of an alcohol is when it reacts with oxygen in the air to form water and carbon dioxide.

In this process energy is required to break the existing chemical bonds (endothermic reaction) and energy is given out by the creation of new chemical bonds (exothermic reaction).

 If the heat of combustion is a -ΔH the reaction is exothermic as the products of combustion are at a lower energy level than the reactants. The energy is given out when forming the bonds between the new water and the carbon dioxide molecules. Here are the balanced equations for the alcohols that I will be using:

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Methanol –         CH3OH + 11/2O2 → CO2  + 2H2O

Ethanol –         C2H5OH + 3O2  2CO2  + 3H2O

Propanol –         C3H7OH + 41/2O2 →3 CO2  + 4H2O

Butanol –         C4H9OH + 6O2 → 4CO2  + 5H2O

Pentanol –         C5H11OH + 71/2O2 → 5CO2  + 6H2O

Hexanol –         C6H13OH + 9O2 → 6CO2  + 7H2O

Heptanol –         C7H15OH + 101/2O2 → 7CO2  + 8H2O

Octanol –        C8H17OH + 12O2 → 8CO2  + 9H2O

 

Firstly to ensure that there is a link between the number of carbon atoms in alcohols and the enthalpy of combustion I shall carry out a preliminary ...

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