Enthalpy of Combustion of Alcohols

The alcohol combustion enthalpy program 1503 cold water was added to the aluminum calorimeter and the temperature was recorded. Support a calorimeter with a spirit burner containing ethanol you burn. Please arrange an appropriate draft removal system to reduce heat loss. Weigh the burner and alcohol. Attach the burner under the calorimeter and light the core. Stir the water with a thermometer. As the water temperature rises by 15 - 20 ° C, the burner disappears but stirring continues until the temperature does not rise.

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.

The change in enthalpy of fuel combustion is a measure of the energy supplied when 1 mole of fuel is completely burned. The value of the enthalpy change can be obtained by heating the water with the burned fuel and raising the temperature of 1 g of water by 1 ° C. with the energy required 2 g. In this survey, by examining the combustion enthalpy change of many alcohols, we were able to investigate how and why the change depends on the molecular structure of alcohol.

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.