Enthalpy of Neutralisation Lab Report Example | Topics and Well Written Essays - 500 words

Enthalpy of Neutralisation - Lab Report Example As a matter of fact, this variation is attributed to the fact that when a strong acid is used, full ionization takes place while with a weak acid; ionization is incomplete (Jarvis, 2011). In this experiment, NaOH is mixed with HCL and later with CH3COOH. Place 500 mL of water into the calorimeter and add 150 mL of 1.0 M sodium hydroxide. Measure 160 mL (an excess) of 1.0 M hydrochloric acid into a 400 mL beaker. Start the stopwatch and stir the two solutions with separate stirring rods and measure their temperatures (use separate thermometers) at 30 s intervals as above. (DO NOT stir the solutions with the thermometers.) After 5 min (do not reset timer to zero) rapidly, but quantitatively, pour the HCl into the calorimeter. Replace the stopper. Continue stirring and record the temperature of the reaction mixture at 30 s intervals for the next 5 min. After the experiment is completed, test the solution with two drops of phenolphthalein. If the reaction mixture is alkaline, insufficient acid has been added and the results are worthless † start again. The first part of the experiment is about reactions between fully ionized strong acids and strong bases and the sole real chemical change is formation of water molecule from hydrogen ions and hydroxide ions. This is given as follows, Evidently, the reaction between NaOH and HCL yields a higher enthalpy of neutralization as compared to the reaction between NaOH and CH3COOH. This is attributed to the fact that the enthalpy of neutralization of a NaOH with a HCL involves complete ionization of the dilute aqueous solutions and hence the reaction involves higher energy. In the case of CH3COOH, while NaOH undergoes complete ionization, CH3COOH only partly ionizes and as a result the enthalpy of neutralization is lower. There are various methods used in measurement of such heat. Initially measurements were premised on simple thermometric