Determining the enthalpy of a reaction – Studying rate of a reaction

CB-IN-42/EV: This test enables to measure the enthalpy variation (ΔH) in an open system at constant pressure, without significant volume variations; this measurement, carried out indirectly, concerns the reaction heat (Q) that is equal to ΔH. The test is carried out in three phases: first of all the solution heat of sodium hydroxide in water is measured, then the heat of neutralization of the reaction between sodium hydroxide and hydrochloric acid will be measured. At last Hess’s law is verified: sodium hydroxide is directly dissolved into hydrochloric acid (single-stage reaction) and students check whether there are differences between the achieved result and the sum of the energies measured in the first two phases (two-stage reaction). CB-IN-43/EV: This kit enables to study the effect of some parameters on the rate of a chemical reaction, and consequently on the time spent in the development of the same reaction. In detail, the first section will analyze the influence of the concentration of reactants emphasizing that as the concentration of reactants increases, the reaction time will decrease; the second section will examine the influence of temperature; as regards the proposed reaction, favoured by high temperatures, the reaction rate will accelerate as this parameter increases; the third section will show how a catalyst can affect the reaction rate; in detail, the reaction will be favoured by a positive catalyst. Finally the influence of the surface of reactants on the same rate will be examined.