Heat Of Formation Of Nacl Essay

1151 Words5 Pages
Kim B. Dy 7F Experiment #5 Heat of Formation of NaCl(s) October 28, 2015 ABSTRACT In Heat of Formation of NaCl(s), two chemical reactions in the form of the neutralization between NaOH(aq) and HCl(aq) and the dissolution of NaCl(s) to NaCl(aq) were performed. Calorimetry and the First Law of Thermodynamics were employed to find out the respective enthalpies of the reactions. These two values completed the Table of Thermochemical Equations given and with respect to Hess’s Law, the heat of formation of solid NaCl was computed by adding the enthalpies in the table. Two Styrofoam cups and a thermometer through its lid served as the calorimeter where the reactions took place. Using the heat transfer equation, the enthalpy of the first reaction was computed to be -1.080 kJ/mol. On the other hand, the enthalpy of the second reaction was +1.409 kJ/mol. The first reaction had a negative enthalpy and was therefore an exothermic reaction. The positive enthalpy of the second reaction showed that it was endothermic. Given the completed Table of Thermochemical Equations, the total of enthalpies was computed to be -355.521 kJ/mol. INTRODUCTION…show more content…
Chemical reactions transform bond energy into heat or work. Enthalpy of reaction (Hrxn) is the term used for the change in heat as a reaction is carried out at constant pressure. It is a state function as it only depends on the final and initial conditions during the change of state. If Hrxn < 0, the system releases heat and is therefore an exothermic reaction. On the other hand, if Hrxn > 0, the system absorbs heat. Hence, the reaction is endothermic. The enthalpy may be measured through a calorimeter and the First Law of Thermodynamics (Law of Conservation of

More about Heat Of Formation Of Nacl Essay

Open Document