Aim: To investigate the effect of change in length of the carbon chain and the position of the functional group (-OH group) on the enthalpy of combustion of alcohol
Variables:
Table 1.1: List of all variables used in the experiment
Type of Variable Name of the Variable
(For trial 1: To investigate the effect of change in length of carbon chain on the enthalpy of combustion of alcohol) Name of the variable
(for trial 2: To investigate the effect of change in position of the OH group on the enthalpy of combustion of alcohol)
Independent Length of the carbon chain in the molecule of the alcohol 1. Position of the functional group (i.e. –OH group) in the molecule of the alcohol
Dependent Heat produced by the combustion of the alcohol
Controlled Mass …show more content…
Thus, in the equation for the enthalpy of combustion of the alcohol Q=mc∆θ, we need to keep the ‘m’ (i.e. mass of the alcohol burned) constant, as all other parameters other than the change in temperature (∆θ) in this equation need to be kept constant to accurately measure the variation of enthalpy of combustion (‘Q’) for different types of alcohols. This allows for a standard ground of comparison between the alcohols of different …show more content…
of carbon atoms in one molecule of the alcohol). Like all hydrocarbons, they also burn in oxygen to form carbon-di-oxide and water with the release of significant amount of energy. This process is known as complete combustion. Since, this reaction causes release in energy to the atmosphere and decrease in energy of the alcohol, it can be characterized as an exothermic reaction.
The amount of energy released by this reaction depends primarily on the number of carbon atoms in the alcohol. The amount of energy released by the complete combustion of a compound per mol is defined as the enthalpy of combustion. We can deduce this as the enthalpy of combustion of methanol (CH3OH) is -726 KJ/mol, and the enthalpy of combustion of ethanol (C2H5OH) is -1367 KJ/mol. As we can see the absolute value of the enthalpy of combustion of ethanol (i.e. 1367 KJ/mol) is much greater than the absolute value of the enthalpy of combustion of methanol (i.e. 726
Variables:
Table 1.1: List of all variables used in the experiment
Type of Variable Name of the Variable
(For trial 1: To investigate the effect of change in length of carbon chain on the enthalpy of combustion of alcohol) Name of the variable
(for trial 2: To investigate the effect of change in position of the OH group on the enthalpy of combustion of alcohol)
Independent Length of the carbon chain in the molecule of the alcohol 1. Position of the functional group (i.e. –OH group) in the molecule of the alcohol
Dependent Heat produced by the combustion of the alcohol
Controlled Mass …show more content…
Thus, in the equation for the enthalpy of combustion of the alcohol Q=mc∆θ, we need to keep the ‘m’ (i.e. mass of the alcohol burned) constant, as all other parameters other than the change in temperature (∆θ) in this equation need to be kept constant to accurately measure the variation of enthalpy of combustion (‘Q’) for different types of alcohols. This allows for a standard ground of comparison between the alcohols of different …show more content…
of carbon atoms in one molecule of the alcohol). Like all hydrocarbons, they also burn in oxygen to form carbon-di-oxide and water with the release of significant amount of energy. This process is known as complete combustion. Since, this reaction causes release in energy to the atmosphere and decrease in energy of the alcohol, it can be characterized as an exothermic reaction.
The amount of energy released by this reaction depends primarily on the number of carbon atoms in the alcohol. The amount of energy released by the complete combustion of a compound per mol is defined as the enthalpy of combustion. We can deduce this as the enthalpy of combustion of methanol (CH3OH) is -726 KJ/mol, and the enthalpy of combustion of ethanol (C2H5OH) is -1367 KJ/mol. As we can see the absolute value of the enthalpy of combustion of ethanol (i.e. 1367 KJ/mol) is much greater than the absolute value of the enthalpy of combustion of methanol (i.e. 726