Determination of the Enthalpy of Reaction of a Monobasic Acid with Sodium Hydroxide

1863 Words Jun 12th, 2012 8 Pages
Title : Expt.1 Determination of the enthalpy (heat) of reaction of a monobasic acid with sodium hydroxide Experiment no : 1 Experiment title : Determination of the enthalpy (heat) of reaction of a monobasic acid with sodium hydroxide Objectives: 1) To understand the enthalpy chemistry. 2) To determine the calorimeter constant. 3) To determine the enthalpy reaction of acid-base reactions. 4) To study the exothermic reaction. Apparatus and Materials : * Dewar flask, stopwatch, thermometer (5 to 50 ˚C, graduated in 1/10 ˚C), * 50 cm3 graduated pipette fitted with a suction bulb, 10 cm3 graduated cylinder, * Conc. sulphuric acid (specific gravity 1.84, 98.5% H2SO4 ), conc. nitric acid, * 1 M …show more content…
C. Enthalpy of reaction II 1) Another set of experiment was carried out as described in experiment B but the mixture in calorimeter was substituted with 100 cm3 of distilled water. 2) Temperature observations were carried out as described in the previous experiments. 3) The temperature changes that took place was recorded. Results and Discussion A. Calorimeter constant From Graph 1 (Refer to graphs behind ), ∆T1 = ( 38.0 -32.0 ) ˚C = 6.0 ˚C | Initial volume of NaOH, cm3 | Final volume of NaOH, cm3 | Total volume of NaOH used, cm3 | First titration | 25.0 | 43.5 | 18.5 | Second titration | 13.4 | 29.4 | 16.0 | Third titration | 20.1 | 37.3 | 17.2 | Average volume of NaOH required to neutralize sulphuric acid in the mixture, = (18.5 + 16.0 + 17.2 )/ 3 = 17.2 Moles of NaOH used = 1 M x (17.2/1000) dm3 = 0.0172 moles H2SO4 + 2 NaOH → Na2SO4 + 2 H2O 2 moles of NaOH is required to neutralize 1 moles of H2SO4. Hence, Moles of H2SO4 used = ½ x 0.0172 moles = 8.6 x 10-3 moles Molarity of H2SO4 = 8.6 x 10-3 / ( 25/1000 ) dm3 = 0.344 M By using the values calculated, 0.344 M in Graph 2 (Refer to graphs behind ) , we can
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