Comparing the Enthalpy Changes of Combustion of Different Alcohols

Comparison of Evolution of Different Alcohol Combustion In this study we will discover the difference in combustion enthalpy of six different alcohols. They are methanol, ethanol, butan-2-ol, propan-1-ol, propan-2-ol and 2 methylpropan-1-ol. Then I can find the difference between linear and branched molecules and isomers. Plan -------- METHOD ------ To run experimental experiments, I fill my calorimeter with 75 grams of water.

Investigate the change in the enthalpy of combustion of alcohol homologs. When carbon alcohol is burned, we study how alcohol with increased amount of carbon affects metamorphism. The energy released by alcohol when it is used is called the enthalpy of combustion. By using what I already have, I think alcohol with a large number of carbon atoms in the molecule will have greater alcohol change than alcohol with fewer carbon atoms. Therefore, as the molecular weight increases, I predict that the enthalpy of combustion increases.

Since a substance (fuel) releases energy by combustion (temperature rise), the combustion reaction is always exothermic, where the change of 焓 () is negative. All fuels for this experiment are a mixture of alcohol-ethanol, 1-pentanol and two different ratios (90%: 10%; 80%: 20%), which are the most common organic compounds is. Alcohols contain hydroxyl functional groups (--OH) attached to alkyl carbon atoms (Figure 1) (Chemwiki, 2014). The classification of alcohol depends on the number of carbon atoms attached to the carbon atom to which the OH group is attached. Both ethanol and 1-pentanol are primary alcohols () and only one carbon atom is attached to the OH group on the carbon atom (Chemiwiki, 2014). Secondary () alcohols and tertiary () alcohols are when 2 and 3 carbon atoms are attached to OH groups on carbon atoms, but they are not used in the experiment.