A kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid :: GCSE Chemistry Coursework Investigation

A kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid Aim: To carry out a complete kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid: Equation: Na2S2O3(aq) + 2HCl(aq) 2NaCl(aq) + S(s) + SO2(g) + H2O(l) PART A To deduce the order of the reaction with respect to the concentrations of sodium thiosulphate and hydrochloric acid the experiment will be carried out at constant temperature and the time interval between the addition of HCl and the obscuring of the ink cross on white paper by the solid yellow sulphur precipitate will be measured for a constant volume of solution that uses 3 varying concentrations of Na2S2O3(aq) while maintaining the concentration of HCl(aq) and 3 varying concentrations of HCl(aq) while maintaining the concentration of Na2S2O3(aq). The rate of the reaction can be determined by the calculating the amount of sulphur produced in the time recorded. This is given by the equation: Rate = Amount of sulphur Time The amount of sulphur needed to obscure the cross is assumed to be the same in each reaction so therefore, Rate = 1 Time Then, the data will be placed in a table to determine the effect of concentration on the rate of reaction and hence the order of both reactants can be formed. Adding up both orders of the reactants gives the overall order of the reaction. PART B To find out the effect of temperature on the rate of the reaction the time interval between the addition of HCl and the obscuring of the ink cross on white paper by the solid yellow sulphur precipitate at five different temperatures must be recorded. A graph showing time taken vs. temperature will produce a curve showing the effect of varying temperature on the rate of reaction. The Arrhenius equation ln k = ln A – (Ea / RT) can be shown graphically by plotting a graph of ln (t) against ln (1/T). The gradient of this graph = - (Ea / RT) which can be used to calculate activation energy. The y-intercept of the line = ln A where A is the Arrhenius constant for the reaction. Hypothesis: The rate of a chemical reaction can be obtained by finding out the change in amount (or concentration) of a particular reactant or product over the time taken for this change. Many factors affect the rate of a reaction, one of which is concentration. For any reaction to happen, the reactant particles must first collide. This is true whether both particles are in solution, or whether one is in solution and the other is a solid. If the concentration is higher, there are more particles in the same volume A kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid :: GCSE Chemistry Coursework Investigation A kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid Aim: To carry out a complete kinetic study of the reaction between aqueous sodium thiosulphate and hydrochloric acid: Equation: Na2S2O3(aq) + 2HCl(aq) 2NaCl(aq) + S(s) + SO2(g) + H2O(l) PART A To deduce the order of the reaction with respect to the concentrations of sodium thiosulphate and hydrochloric acid the experiment will be carried out at constant temperature and the time interval between the addition of HCl and the obscuring of the ink cross on white paper by the solid yellow sulphur precipitate will be measured for a constant volume of solution that uses 3 varying concentrations of Na2S2O3(aq) while maintaining the concentration of HCl(aq) and 3 varying concentrations of HCl(aq) while maintaining the concentration of Na2S2O3(aq). The rate of the reaction can be determined by the calculating the amount of sulphur produced in the time recorded. This is given by the equation: Rate = Amount of sulphur Time The amount of sulphur needed to obscure the cross is assumed to be the same in each reaction so therefore, Rate = 1 Time Then, the data will be placed in a table to determine the effect of concentration on the rate of reaction and hence the order of both reactants can be formed. Adding up both orders of the reactants gives the overall order of the reaction. PART B To find out the effect of temperature on the rate of the reaction the time interval between the addition of HCl and the obscuring of the ink cross on white paper by the solid yellow sulphur precipitate at five different temperatures must be recorded. A graph showing time taken vs. temperature will produce a curve showing the effect of varying temperature on the rate of reaction. The Arrhenius equation ln k = ln A – (Ea / RT) can be shown graphically by plotting a graph of ln (t) against ln (1/T). The gradient of this graph = - (Ea / RT) which can be used to calculate activation energy. The y-intercept of the line = ln A where A is the Arrhenius constant for the reaction. Hypothesis: The rate of a chemical reaction can be obtained by finding out the change in amount (or concentration) of a particular reactant or product over the time taken for this change. Many factors affect the rate of a reaction, one of which is concentration. For any reaction to happen, the reactant particles must first collide. This is true whether both particles are in solution, or whether one is in solution and the other is a solid. If the concentration is higher, there are more particles in the same volume