# Experiment 3 notes.docx - Experiment 3 The Heat of...

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Experiment 3: The Heat of Ionization of a Weak Acid
Introduction The purpose of Experiment 3: The Heat of Ionization of a Weak Acid is to measure enthalpy changes, including the neutralization of an acid by a base, through calorimetry. The present experiment is demonstrating thermochemistry concerned with heat changes. The basis of thermochemistry relies on the three laws of thermodynamics. The First Law of Thermodynamics states that energy may be converted from one form to another, but it remains constant. The First Law of Thermodynamics is represented by the equation E = q + w, where E represents the total energy of the system, q is the heat gained by the system and w is the work done on the system. The Second Law of Thermodynamics states that the entropy of an isolated system will always increase over time and changes in entropy in an isolated system can never be negative. The Second Law of Thermodynamics informs the value of heat capacity such that when hot water is added to cold water the temperature can not be higher than the equilibrium between the two. The Third Law of Thermodynamics states that the entropy of a pure substance at 0 K is zero. In the present experiment a Styrofoam cup is utilized as a calorimeter. According to the lab manual the temperature change occurring in the calorimeter if the total heat capacity of the system is known. q p = C p T where C p represents the total heat capacity of the system at constant pressure T = T final – T initial In order to measure the heat capacity of all the parts of the system experimentally, the
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