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Introduction

University Tunku Abdul Rahman (Kampar Campus) Bachelor of Science (Hons) Biotechnology Year 1 Trimester 1 Group 1 Laboratory Chemistry II (UDEC 1144) Lecturer : Dr. Yip Foo Win Student's Name : Panmalar D/O Krishnamoorty Student's ID : 09UHF07367 Experiment Number : 1 Title : Determination of the Enthalpy (Heat) of Reaction of a Monobasic Acid with Sodium Hydroxide TITLE : Determination of the Enthalpy (heat)of reaction of a Monobasic acid with Sodium Hydroxide OBJECTIVES : To determine the calorimeter constant To determine the enthalpy of concentrated nitric acid with Sodium Hydroxide INTRODUCTION : In thermodynamics, the enthalpy (denoted as H, or specific enthalpy denoted as H) is a thermodynamic property of a fluid. This heat of reaction which is taking place in a closed thermodynamic system under constant pressure is measured adiabatically in a Dewar calorimeter based on the changes in temperature of the products produced by the reaction in solution. The "calorimeter constant" must first be determined. This is the quantity of heat required to increase the temperature of the calorimeter and it's contents by 1 �C. The constant is measured by supplying the calorimeter and contents with a definite known quantity of heat. This can be done electrically or by adding known amount of conc. sulphuric acid. METHOD : Part 1: Determination of Calorimeter Constant 1. 100 cm� of water was pipette into the Dewar flask. ...read more.

Middle

(Before added HNO3) 26 26 26 26 26 26 26 26 26 26 Temperature, t ( �C) (After added HNO3) 34 34 33 33 32.5 32 32 32 32 32 Table 3: Temperature of water before and after the addition of nitric acid solution in the calorimeter. Time (min) 1 2 3 4 5 6 7 8 9 10 Temperature, t ( �C) (Before added HNO3) 25 25 25 25 25 25 25 25 25 25 Temperature, t ( �C) (After added HNO3) 27 27 27 27 27 27 27 27 27 27 From graph 1, The change in temperature, ?T = 5.0 �C Volume of NaOH solution = 17.50 cm� 2NaOH + H2SO4 -->Na2SO4 + 2H2O 17.50 cm� of 1M sodium hydroxide solution required to titrate the 25.0 cm� of sulphuric acid solution 1 mole of sodium hydroxide produces 1 mole of hydroxide ions when dissolved in water. Number of moles of NaOH required in the titration = MV 1000 = (17.50 cm� )(1M) 1000 = 0.0175 mole Number of moles of hydroxide ions = 0.0175 mole 1 mole of sulphuric acid produces 2 moles of hydroxonium ions when dissolved in water. 1 mole of hydroxonium ions reacts with 1 mole of hydroxide ions; therefore, 0.0175 moles of hydroxonium ions react with 0.0175 moles of hydroxide ions. Number of moles of hydroxonium ions = 0.0175 mole Number of moles of sulphuric acid = 0.0175mol 2 = 0.00875 mole MV = 0.00875 mole 1000 (25.0 cm� )(M) ...read more.

Conclusion

+ O2 (g) Sodium nitrate is slightly deliquescent and gets wet. Hence it cannot be used in making gun powder like the potassium salt. By mixing Sodium Hydroxide, NaOH with sulphuric acid, H2SO4 nitric acid,HNO3 can be produced. Further fractional distillation of HNO3will produce sodium bisulphate. All the acids have hydrogen in common. The hydrogen present in acids is such that when acid is dissolved in water, it separates out as positively charged hydrogen ions and enters the solution as H+ ions.It is the presence of hydrogen ions in hydrochloric acid solution, which makes it behave like an acid.Hydrogen ions do not exist as H+ ions in solution, they attach themselves to the polar water molecules to form hydronium ions, H3O+Thus, the acidic behaviour of an acid solution is due to the presence of hydrogen ions in it. On the basis of these replaceable hydrogen ions, acids are of following types: * A monobasic acid is the acid that has one replaceable hydrogen atom to give to the base in any acid-base reaction such as HCl, HNO3 * A dibasic acid has two replaceable hydrogen atoms for the reactions such as H2SO4. * A tribasic acid has three replaceable hydrogen atoms such as H3PO4. Monobasic acid, HCl has few properties which explain an acid. When hydrochloric acid, HCL reacts with sodium hydroxide, NaOH solution, then a neutralization reaction takes place to form sodium chloride, NaCL and water. Solution of hydrochloric acid, HCl reacts with crushed eggshells to give a gas (carbon dioxide) that turns lime water milky. REFERANCE : http://www.tutorvista.com/bow/enthalpy-definition http://www.science.uwaterloo.ca/~cchieh/cact/c120/heatreac.html http://www.ausetute.com.au/heatform.html http://www.tutorvista.com/chemistry/what-is-calorimeter-constant http://www.tutorvista.com/chemistry/sodium-hydroxide-reacts-with-nitric-acid http://www.tutorvista.com/chemistry/types-of-acids-monobasic http://www.tutorvista.com/content/chemistry/chemistry-ii/nitrogen/common-nitrates.php http://www.tutorvista.com/content/chemistry/chemistry-iii/thermodynamics/enthalpy-change.php ...read more.

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