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TitleData Logging On Determination The Hydration Enthalpy Of An Electrolyte.IntroductionWhat is Data Logging? Data logging is the process of using computer to collect data through sensors,analyze the data and save the output the results of the collection and analysis. Data loggingis also implies the control of how the computer collects and analyzes the data. Data loggingis commonly used in scientific experiments and monitoring systems where there is the needto collect information faster than a human can possibly collect the information and in thiscase the accuracy is essential. Examples of the types of information and a data loggingsystem can collect include temperatures, sound frequencies, vibrations, times, lightintensities, electrical currents, pressures and changes in states of matter. Computer datalogging has been used in teaching science in number of countries since the 1980s. Assummary, a collection of results is known as data while the process of handling data byusing modern computer technology referred to as data logging.Elements of Data Logging Data logging system consists of sensor, interface box and computer with appropriatesoftware. A sensor is a device that responds to some physical property of the environmentlike temperature, pressure, light intensity, voltage, current and many more. Then, thevariation of physical properties is converted into signals that is recognized by a device calledinterface box. The interface box is used to convert the signal of the sensor to a digital signalwhich is can be read by the computer. The interface will connected to the computer via aserial port of computer. Then, computer is used to display the data and read the informationfrom sensor. Specialised computer software is required so that the computer can interpretand process the signals from the interface box. Examples of data logging software such asData Studio, HOBOware and many more. The sensors, interface box, computer andappropriate computer software called as the data logging system.Advantages the Use of Data Logging in Science Teaching From research that have been carried out, data logging can improves graphingskills of students and help them to form links between what they have learnt in class withthe process of investigating scientific relationships. The interpretations of graphs issignificantly improved as they have applied the skills of real-time reporting where the graph
is drawn at the same time as the experiment is performed will encourage reflection andinterpretation among students. Apart from that, computer data logging practical work also will give more benefitscompared to the conventional approach in the presentation of data. By using data logging,the quality of written homework was greatly improved as the data can be easilymanipulated and presented in the form of clearly drawn graphs. Real-time data loggingpresents the graph on the screen “as it happens” and this is especially beneficial to the lessable student. Data logging also can save times in pattern of student‟s activity in preparingapparatus and materials, measuring and reporting data towards spent more on observation,manipulation of data and discussion among students of the results obtained when using thisdata logging system. The automatic logging of experimental data and graphicalrepresentations allowed for more focused approach to changes in experimental variablesand discussion of results. It was clear that they have better insight into this experimentalwork being performed. Besides, students need to take less prolonged readings and throughthe software they can spend more time in analysing information. The immediate visualfeedback via the computer enables „on the fly‟ adjustment to experiments. In addition,without the aid of computer data logging spent more considerably more time in datacollection. In general, we can see that students find information technology to be a goodstimulus for learning. The software tools for calculation and analysis will reduce tasksconsidered to be tedious and repetitive into creative opportunities for carrying outinvestigation in laboratory. This will increased level of interest among students in bringingscience teaching and learning process into twenty-first century. Data logger also allows students to collect data from whole range of sources atone particular time. For example, in evaporation experiment they are not just onlymeasuring the temperature today, but three or fours variables that might be affecting theoutcome of evaporation. Students are able to collect information anywhere and anytime,which means a whole community potentially becomes part of the learning environment.Disadvantages the Use of Data Logging in Science Teaching One of the disadvantages of using data logging is the special features of data logginggraphing software sometimes gives the variaties of difficulties associated in handling thedata logging software, They need to setup the software more wisely and carefully so that itdoes not gives not accurate and not precise result when it was displayed on the computer. Ifit was happened, they need to modifiy any devices related so that it can be function well.
Besides, by using data logging, the students will face difficulties if the devices orequipments are broken or cannot be function well. So, they need times in repairing thedevices so that they can use to run their experiment. The data logging and computerizeddevices really need meticulous care as there are really sensitive tools.Experiment : Determination Of The Hydration Enthalpy Of An ElectrolyteTheoryThe dissolution of a solid electrolyte in water is primary determined by two simultaneouslyoccur in processes : the destruction of the crystal lattice and the hydration of the ions.The degradation of the crystal lattice is an endothermic process because energy is requiredto breakdown the chemical bonds, whereas the hydration of the ions is exothermic.Depending on the type of lattice, and both the radius and the charge of the ions (chargedensity), the resulting enthalpy of the solution can be either or exothermic.When a salt exists in both hydrated and dehydrated forms, and one assumes that during thedissolution of the hydrated salt only the degradation of the crystal lattice occurs, the enthalpyof hydration can be calculated with Hess‟s theorem (Figure 1). ] (s) [ 5 ] (s) Cu2+ (aq) 2- (aq)
= (1.1) = - (1.2) Enthalpy of hydration Integral enthalpy of solutionThe integral enthalpy of solution can be calculated according to equation = (1.3) = (1.4) Heat of solution of a salt Electrical work for calibration Corrected temperature difference during the dissolution of the salt Corrected temperature difference during the calibration Quantity of salt
I. Engage (a) (b) Picture (a) is about the process melting of an ice while picture (b) is about theprocess of freezing of an ice. In processes, heat or energy is involved. But, there are somedifferent either heat absorbed or heat released. Reaction that release heat termedexothermic while reaction that absorbed heat termed endothermic. Which one of this pictureis exothermic reaction? Which one of this picture endothermic reaction? How thetemperature or heat of the surrounding changes? In this experiment, anhydrous copper (II) sulphate and copper (II) sulphate wereused. Both compounds are made up of copper and sulphate but one of them contain watermolecule while the other one do not contain water molecule. Most of the people always havemisconception about the molecular formula of copper (II) sulphate and anhydrous copper (II)sulphate. Most of them think that the molecular formula of anhydrous copper (II) sulphate isCuSO4.5H2O while the molecular formula of copper (II) sulphate is CuSO4. Actually, anhydrous copper (II) sulphate is molecule without molecule of water butcopper (II) sulphate is molecule with water. So, the actual molecular formulae of anhydrouscopper (II) sulphate is CuSO4 while the molecular formula of copper (II) sulphate isCuSO4.5H2O But, is both of them have same type of enthalpy? If both of them have sametype of enthalpy, which one of them has highest enthalpy value? Which one undergoesexothermic process and which one undergo endothermic process? Engage is the process to generate idea or to induce any idea about the topic. Theteacher can use the phenomenon happen in our life, video simulation or figures and picturesto make the students able to think why it happened. In this experiment, we have used theformation of ice and the melting of ice to relate both of these situations with endothermic andexothermic reaction so that the students can start to think. In engage stage, the students willstart to explore about the topic, start to think abstractly and start to formulate and developthe concepts.
II. EmpowerMethod 1) First, the experiment set-up is performed. 2) Then, 24.97g (0.1 mol) of copper (II) sulphate and 15.96g (0.1 mol) of anhydrous copper (II) sulphate, which has been finely pulverized in a mortar are weighed. 3) The calorimeter is filled with 900mL of distilled water. The magnetic stirring bar is put into the calorimeter and latter is placed onto heating stirrer. 4) After attaching the heating coil and the temperature probe, the magnetic stirrer is switched on. Please be aware, do not mistakenly switch on the heating unit. 5) When the equilibrium temperature has been reached in the calorimeter approximately 5 minutes, the first copper salt is added to the water by pouring it through powder funnel which has been inserted in the opening in the lid. While doing so, make sure the entire quantity of salt is added to the water without any loss. 6) The registration of the temperature-time curve is begun first. 7) Ten minutes after the salt has completely dissolved, the electrical calibration* is conducted in order to determine the total heat capacity of the calorimeter. *10AV is supplied to the work and power meter for the electrical heating. Performed a reset and then the free ends of the heating coil‟s connection cables are plugged into the output jacks of the work and power meter. The system is heated continuously, and the supplied quantity of energy is measured. After electrical energy amounting to approximately 4000Ws has been supplied, the heating is switched off and the exact quantity of electrical energy is read from the meter. 8) 10 minutes later the temperature recording is also terminated. 9) The corrected temperature differences, ∆T for the calibration and solution experiment are determined are determined as shown in Figure 2.
10) This correction is necessary because of the heat exchange with the surroundings. The vertical straight line which intersects the lines and are drawn in such a manner that the shaded areas are equal size. 11) For the calibration, is determined analogously from the intersection points of . 12) The same experiment is repeated to determine the enthalpy of solution for both Copper (II) sulphates. At least two measurements should be performed for each salt to avoid errors and to be able to calculate the mean value.Figure 2 : Graphical determination of the correct T values from the temperature time curve.
Figure 1 : Apparatus set upFigure 2 :Picture of sensor
ResultA) Solution of copper (II) sulphate, 5 Time, s Temperature, K Notes 0.96 30 0.96 60 0.88 90 0.63 120 0.37 150 + 5 0.15 180 0.11 210 0.09 240 0.09 270 + 5 0.06 300 4057Ws 0.02 330 0.02 360 0.01 390
Graph temperature Vs. time of copper (II) sulphate 1 0.9 0.88 0.8 0.7 0.63 0.6Temperature, K 0.5 0.96 0.4 0.37 0.3 0.2 0.15 0.11 0.1 0.09 0.09 0.06 0.02 0.02 0.01 0 0 50 100 150 200 250 300 350 400 450 Time, s Graph 1
Mass of 5 = 24.976gMole of 5 = = 0.1 = 0.0.09 - 0.02 = 0.07 = 0.06 – 0.09 = -0.03 = = 4057 = 9466JIntegral enthalpy of solution of 5 = = = -94.66 kJ mol-1
B) Solution of anhydrous copper (II) sulphate, CuSO4. Time, s Temperature, K Notes 30 0.01 60 0.03 H2O 90 0.03 120 1.26 150 1.29 180 1.29 H2O + CuSO4 210 1.29 240 1.28 270 1.50 300 1.74 330 2.01 360 2.18 H2O + CuSO4 390 2.18 4066 Ws 420 2.17 450 2.17 480 2.16 510 2.15 540 2.15
Graph temperature against time of anhydrous copper (II) sulphate 2.5 2.18 2.17 2.16 2.15 2.18 2.17 2.15 2.01 2 1.74 1.5 1.5 1.29 1.26 1.28 1.29 1.29Temperature. K 1 0.5 0.03 0.01 0.03 0 0 100 200 300 400 500 600 -0.5 Time, s Graph 2
Mass of CuSO4 = 15.963 gMole of CuSO4 = = 0.1 mole ∆Texp = 1.3 – 0.03 = 1.27 ∆Tcal = 2.19 – 1.29 = 0.90 Qexp = Qcal ∙ = 4066 ∙ = 5738 JIntegral enthalpy of solution of CuSO4 ∆ LH = = = 57.38 kJ mol-1 ∆ H HCuSO4 = ∆ L HCuSO4 - ∆ L HCuSO4.5H20 = 57.38 – (-94.66) = 152.04kJmol-1
Discussion. Hydrates are compounds that incorporate water molecules into their fundamental solid structure. All hydrating water is removed, the material is said to be anhydrous Enthalpy of solution of copper (II) sulphate is exothermic reaction Enthalpy of anhydrous copper (II) sulphate is endothermic reaction The 5H2O in the formula of anhydrous copper(II) sulphate is called the water of crystallisation and forms part of the crystal structure when copper(II) sulphate solution is evaporated and crystals form. This crystal structure is broken down on heating and the water is given off. So, the thermal decomposition is endothermic as heat is absorbed to drive off the water. Meanwhile, the reverse reaction is called as and exothermic reaction. This is because it needs adding water to white anhydrous copper(II) sulphate and the mixture heats up as the blue crystals reform. The reverse reaction is used as a simple chemical test for water where white anhydrous copper(II) sulphate turns blue. The enthalpy change is the „enthalpy change of hydration‟. Enthalpy change of reaction is endothermic reaction. The value of enthalpy change of reaction is 152.04kJmol-1. CuSO4 (s) + 5 H2O (l) → CuSO4 • 5H2O (s) CuSO4 (s) + H 2O(l) → CuSO4 (aq) (ashy white) (deep blue) Empower is something that gaining a power in particular activity by individuals orgroups. It is also the process of giving power to the students or process that foster andfacilitate their taking of power. Besides, empower also a process to achieve goals or someeffort to understand some critical understanding. So, in data logging learning, the teachercan empower their student by performing an experiment so that they can have moreunderstanding about what they have learnt theoretically in class. From data logging process,the method used is by using a sensor and computer rather than using traditional method. So,
the students can see clearly the result. Hence they can make comparison directly betweentheir results with the theory. If there‟s any differences happen, they can make discussionregarding the result they got. The students will construct their concept of learning byunderstanding the process involve in the experiment. In this topic, students may be surprisedthat energy can either be evolved or absorbed in reactions. To make a chemical bond,another bond must first be broken. It is the sum of the energy changes in making andbreaking bonds that results in the overall energy change. If temperature sensors and datalogging equipment are available, they may be appropriate in this context. This is because atemperature sensor attached to a computer can be used in place of a thermometer. It canplot the temperature change on a graph and make a helpful demonstration to the students ofwhat happens when chemicals react. This data logging set up might be the basis for aproject where students have to find the mix of chemicals that yield the optimal heat loss orgain. III. Enhance Cold packs and putting ice in towel causes a cooling effect on their person‟s head and temporarily relieve the pain and fever. Explain. There are two types of cold packs which are small inner bag and an outer bag. Thesmall inner bag can be just water and the outer bag can be ionic salts such as AmmoniumChloride or Potassium Nitrate. When the pack is squeezed, the small inner bag breaks theionic salt dissolves in water. When the cold pack is used, the chemicals inside the pack aremade to react with each other and this reaction is highly endothermic in nature. Endothermicreactions involve the absorption of heat. The ammonium nitrate mixing with the watercreates cold. The temperature of cold packs can reach back to normal temperature. Theheat energy is taken into the system from the surrounding. The surrounding in this case isthe person‟s head.
Another alternative way in reducing headache or fever is by wrapping some ice insidea small towel and hold it against forehead. This is a traditional way practiced by our parent tocool down the temperature and pain. The concept is the same as the cold pack. As the icemelts to become liquid water, it would take in energy from the surroundings and melting isconsidered an endothermic process. The solid ice will become the system and our foreheadbecomes the surrounding. The system takes in heat energy from the surrounding and thusdirectly remove heat from our forehead and can reduce pain. Enhance is something to make it better, to add or contribute to. In data logginglearning, enhance is the third phase after empower stage which is to increase student‟sunderstanding on a given problem or topic by relating it with the example of application. Forexample, if we give some situation or application in our environment or daily life application,the students will be able to relate the reasons of the situation given on what they have learnt.So that, they can apply their learning concept in daily life application in order to enable themto understand and remember. So, in this experiment, we should provide an example relatedto endothermic or exothermic reaction. The students may have developed theirunderstanding about these reactions at empower stage but then when at the enhanceprocess, they just need to add any additional knowledge by relate in with daily lifeapplications.Extension N2 (g) + 3H2 (g) ↔ 2NH3 (g)What will happen to the production of ammonia gas reaction if we increase the concentrationthe temperature of the reactant mixture?If the temperature of a reaction mixture is increase, the equilibrium will shift to decrease thetemperature. Based on Le Chatelier‟s Principle which stated that if a chemical system atequilibrium experiences a change in concentration, temperature or total pressure, theequilibrium will shift in order to minimize that changes a new equilibrium is established. So, ifwe increase the temperature, the equilibrium will shift to the reactant part which is left. So,the reaction will undergo endothermic reaction as it use up heat energy. Ammonia willbroken down into hydrogen and nitrogen gas. An increase in temperature will decrease theyield of ammonia , NH3.
Conclusion As a teacher, we should apply the use of data logger in teaching and learningprocess in line with the developments of technology. The use of this type of teachingprocess can enhance the learning style and gives the positive impact on teaching Scienceprocess especially. Teacher will use the three steps in data logging process like engage,empower and enhance to make the students get highly understanding about what they havelearnt. Usually during science theory classes, students do not have the opportunity toverify the appropriateness of the information that the teacher is putting forward. So, the useof technology which incorporates data logging will significantly ease the situation and able todevelop logical understanding of the abstract concept. At the same time, they can obtain theinformation on the truthfulness of the underlying processes. The use of data logging willbring cognitive acceleration to learning, as the teachers can support their teaching withundeniable facts, thus students can be able to revisit any misconception they hold on thespot.ReferencesA.Gras-Velazquez, A.Joyce and M. Le Boniec. Impact of Data Loggers on Science Teaching and Learning. Retrieved on 27 Dec. 2012 from http://files.eun.org/netbooks/ACER_Fourier_EUN_Science_pilot_report_2012.pdfData Logger. Retrieved on 27 Dec. 2012from en.wikipedia.org/wiki/Data_loggerDeclan Kennedy (2000). The Use of Data Laogging in Teaching Physics and Chemistry in Second-Level Schools in Ireland. Retrieved on 27 Dec.2012 from http://www.outlab.ie/forums/documents/the_use_of_datalogging_in_teaching_physics_a nd_chem_in_second_level_schools_report_ie_111.pdfEngaged Learning. Retrieved on 29 Dec. 2012 fromhttp://www.gcms.k12.il.us/kummerow/engagedlearn.htmLorraine Stefani (2008). Engaging our Students in the Learning Process : Points for Consideration. Journal of International Journal for the Scholarship of Teaching and Learning. Vol. 2, No. 1. Retrieved on 28 Dec. 2012 from http://academics.georgiasouthern.edu/ijsotl/v2n1/invited_essays/Stefani/Invited_Essay_ Stefani.pdfUsing ICT and Data Logging in Teaching and Learning of Science. Retrieved on 27 Dec.2012 from http://www.gov.mu/portal/goc/educationsite/file/inside.pdfTechnology-integrated Science Teaching. Retrieved on 28 Dec. 2012 fromwww.educ.cam.ac.uk/research/projects/istl/ScT2.doc