'Ib Chemistry Experiment- Calculating Enthalpy Change\r'

'Chemis prove Internal Assessment: determine the Enthalpy Change of a Displacement chemical response AIM: To determine the henry agitate for the reception between copper(II) sulfate and zinc. BACKGROUND THEORY: stupefy breaking is endothermic while bond forming is exothermic. The reaction between copper(ll) sulfate and zinc is exothermic as the heftiness required to form the bonds of the products is greater than the energy required to break the bonds of the reactants. In an exothermic reaction, light up is given collide with to the surroundings; thus, temperature of the surroundings lead increase. By measuring the change in the temperature and utilise the jurisprudence Q= mc?T, we layabout calculate the enthalpy change of the reaction. Equation 1: CuSO4 + Zn ? ZnSO4 ionic Equation: Zn (s) + Cu2+ (aq) ? Cu (s) + Zn2+ (aq) MATERIALS/APPARATUS: * 1 insulated Styrofoam cup * Copper(II) sulfate dissolvent * Zinc de counterspyish * 1 Thermometer * 1 S precedewatch * Weighin g boat * Electronic Balance VARIABLES: Independent| Dependent| freshet of zinc powder and concentration of copper(II) sulfate solution used. | Temperature of the solution| PROCEDURE: 1. Use a pipet to measure 25. 0cm3 of 1. 0 M copper(ll) sulfate to the insulated container. 2. indicate the temperature every 30 seconds for 2. 5 minutes 3.Add the excess zing powder (6g) at scarcely 3 minutes 4. Stir and record the temperature every 30 seconds for the following 10 minutes. DATA COLLECTION AND process: Time (s)| Temperature (°C)| Time| Temperature (°C)| 30| 25| 390| 62| 60| 25| 420| 61| 90| 25| 450| 60| 120| 25| 480| 59| cl| 25| 510| 58| 180| 25| 540| 56| 210| 45| 570| 55| 240| 52| 600| 54| 270| 56| 630| 52| 300| 60| 660| 51| 330| 61. 5| 690| 50| 360| 62| 720| 49| Therefore, based on the graph shown above (representing the raw data), the change in temperature if the reaction had call forn place instantaneously with no heat loss: ?T= 70. 5°C ? 25°C 45. 5°C The chrom a of the copper(II) sulfate solution used was 25cm3, thus the caboodle of the solution is 25g. Given that the specialized heat capability of the solution is 4. 18 J/K and the temperature change is 45. 5°C, as calculated above, thus, the heat, in joules, produced during the reaction can be calculated using the formula: Q = mc? T =mass of solution ? specific heat capacity of solution ? temperature change = 25 ? 4. 18 ? 45. 5 = 4754. 75 J In the experiment, 25cm3 of 1. 0 mol dm-3 copper(II) sulfate solution was used. Thus, enumerate of moles of the copper(II) sulfate solution used: n(CuSO4) = (25? 000) ? 1. 0 = 0. 025 mol Therefore, the enthalpy change, in kJ/mol, for this reaction is: ?H = Q ? n(CuSO4) = 4754. 75 ? 0. 025 = -190. 19 kJ/mol Theoretical pry/ original Value= ? 217 kJ/mol Thus, percentage error = [(? 217+190. 19) ? (? 217)] ? atomic number 6 = 12. 35% CONCLUSION Thus, based on the experiment, the enthalpy change for the reaction is -190. 19 kJ/mol. However, as w e can see from the above calculations, the percentage error is 12. 35%. This means that the result is in perfect from the theoretical value of -217 kJ/mol by 12. 35%.From the graph, we can also see that once zinc is added to the solution (at exactly 3 minutes), the temperature of the solution increases until it reaches the terminal or maximum temperature of 61°C. Then, the temperature of the solution gradually decreases until it reaches room temperature once again (temperature of the surroundings). EVALUATION (WHAT CAN BE DONE TO amend THE EXPERIMENT? ) An assumption made for this experiment is that none of the heat produced by the exothermic reaction is broken to the surroundings and that the thermometer records the temperature change accurately. However, this is very unlikely to appen in reality, which would explain the percentage error. Thus, to improve the experiment, we can try to minimize the heat loss to the surroundings. This can be done by place a put in of cardboa rd (or any other insulated material) on top of the cup to cover the top of the cup. A hole out can then be made in the cardboard for the thermometer. Another measure that we can take is to ensure that our eye is level with the thermometer when reading the temperature off the thermometer. We can also repeat the experiment a few times and get the average of the results recorded. This would kick us to obtain a more accurate value.\r\n'