Determination of the Enthalpy Change of a Reaction

The measurement of the reaction enthalpy is based on the indirect method of Hess's law for determining the enthalpy change of thermal decomposition of calcium carbonate. The measurement of the reaction enthalpy is based on the indirect method of Hess's law for determining the enthalpy change of thermal decomposition of calcium carbonate. These values ​​were collected using methods to obtain the proposed results. Reaction 1: CaCO 3 (s) + 2 HCl (aqueous solution) CaCl 2 (aqueous solution) + CO 2 (g) + H 2 O (1) GRAPH = 2 Represents the average of case data.

The first part of the experiment is based on the equilibrium reaction KHC 4 H 4 O 6 (s)> K + (aq) + HC 4 H 4 O 6 to determine the enthalpy and entropy change in the dissolution reaction, hydrogen tartrate in water It was designed to determine the solubility product constant of potassium. - (aq) --- (1), depends on the temperature. The second part of the experiment was designed to detect common ion effects by measuring the Ksp of KHC 4 H 4 O 6 in potassium nitrate (KNO 3) solution of different K + concentration.

When one original bond breaks and a new bond is formed, a chemical reaction is involved in the change in energy. Normally energy changes take the form of heat. When heat is released from the reaction, energy change or enthalpy (ΔH) is negative and the reaction is exothermic. Conversely, when the reaction absorbs heat, the enthalpy becomes positive and the reaction becomes endothermic. In this experiment, acid / base neutralization enthalpy (ΔH) is measured. As shown in the following example, neutralization occurs when acid and base combine to form water. Total reaction: HCl (aqueous solution) + NaOH (aqueous solution) → NaCl (aqueous solution) + H 2 O (1) TIE: H

· Calorimeter - Container for measuring enthalpy · Exothermic reaction - heat is transferred to the surrounding environment, reactants lose energy · enthalpy becomes negative - all reactions generate heat - isothermal reaction - energy is Absorbed and reactant gains energy, enthalpy change will generate positive § functional group - atom or atomic group, homologous sequence. Compounds of the same series show similar chemistry, ie alcohols § general formula - formulas that can be prepared for each family series