Effect Of UV Rays On Pool Chlorine Biology Essay

Effect Of UV Rays On Pool Chlorine Biology EssayPools have always been a opening of leisure for Australians. They provide enjoyment and good generation for legion(predicate) households generated in a family or local swimming pool. Despite this, pools have to be retained by using chemicals or disinfectants, lest unwanted pathogens create health hazards. However, the over use of these chemicals can also result in health hazards such as serious irritation and breathing problems. A balance or equilibrium, therefore, must be achieved to maintain suitable conditions. This is where chemistry comes into play.The main type of chemicals used in pools to prevent unwanted pathogens is pool chlorine. Sodium hypochlorite is a commonly used as pool chlorine. It was discovered by Louis Pasteur in the late 19th carbon that atomic number 11 hypochlorite had disinfectant properties. Sodium hypochlorite effectively kills bacteria, viruses and fungi. When pool chlorine is added to piss, a reaction takes place where hypochlorus acid is formed.In the past, most consumer chlorine bleach was sell in a 5.25% solution. Today, some more concentrated solutions are being sold and touted as an improvement over the less concentrated bleaches.To check for the constriction of the pool chlorine, excess yard iodide is to be added to it and then it is to be titrated with a solution of sodium thiosulfate. The concentration of the liquid chlorine is then to be calculate using stoichiometry. The net ionic equations of the chemical reactions areSource Chemistry In use Book 2There are also many factors that affect the effectiveness of pool chlorine such as sun radiation.Ultra-violet (UV) timid cheapens hypochlorous acid to hydrochloric acid (HCl).Ultraviolet (UV) radiation not only destroys light warm chemicals such as sodium hypochlorite (NaOCl), it also has the potential to significantly degrade the structural integrity of the storage tank or IBC containing the light sensitive material.Ac cording to the NSWMinistry of Health(2010) roughly 1/3 of free chlorine exposed to UV lights in a outdoor swimming pool is undo every hour. UV light therefore lowers the concentration of the disinfection component of free chlorine.In this experiment, the concentration of sodium hypochlorite in pool chlorine, left under a UV lamps for different periods of times, was measured.Aim To investigate the effects of Ultra Violet (UV) rays on sodium hypochlorite (a bleaching agent used commonly in pools).2.0 Hypothesis As pool chlorine is left for longer periods of time under UV rays, the concentration of the pool chlorine will decrease.This was hypothesised as the theory suggests that UV rays degrade the component in pool chlorine which allows it to disinfect bacteria.3.0 Equipment/MaterialMaterialDiluted Sodium hypochloriteSodium thiosulfatePotassium iodideStarch indicatorBoiling weeweeEquipment2 x 100 mL Beaker5 x 250 mL Beaker15 x 100 mL Flask2 x 1L volumetric flask1 x 500 mL Volumetr ic flask1 x 100mL Measuring cylinder2 x 20mL Measuring cylinder3 x Funnel5 x 20 mL Pipette2 x 1mL Pipette3 x Stirring poleSenior BalanceBurette and standUV LampPermanent markerStopwatch4.0 SafetyTo prevent any harm to the group during this experiment, safety precautions were taken to ensure the safety of the members. Refer to vermiform appendix A for MSDS (Material Safety Data Sheet).Lots of glasswork was used Refrain from holding too many pieces of glassware at once. Clean up glass immediately if any is broken.Handle boiling water with care Boiling water was used to create a solution of starch. Beaker tongs were used to carry the boiling water.Potassium iodide is atrocious to eyes and skin Avoid contacting without gloves. Wash with water if contact occurs.Sodium thiosulfate is irritating to eyes and skin Avoid contacting without gloves. Wash with water if contact occurs.Starch gives skin discomfort Avoid contacting without gloves.5.0 ProcedureRefer to Appendix 1 for rea dying of solutionsPreparation of titrationA burette and stand was filtered with the sodium thiosulfate solution.The burette was filled up with the sodium thiosulfate solution to around the 0mL mark.100mL of diluted sodium hypochlorite was poured into 5 various(prenominal) 250mL beakers.These beakers were labelled 0min, 15m, 30m, 1hr, 3hrs and 4hrs.All the beakers, except the 0min beaker, were set(p) under the UV lamp for the amounts of time labelled on them. At this point the stopwatch was started, once the models had reach the qualify time they were taken out.For each time sample, 20mL was measured with a pipette and placed into 3 100mL flasks.10mL of potassium iodide solution and 2mL of starch indicator solution were disposed(p) prior to every titration.TitrationThe mark of where the sodium thiosulfate solution in the burette was recorded before the titration occurred.10mL of potassium iodide solution was added to each time sample of 20mL sodium hypochlorite solution in the 100 mL flasks. The new solution was left until it has completed reacted (when the solution turns light yellow).The solution was then titrated until it turn a very pale yellow.2mL of starch indicator solution was added to the titrating solution. This should make the solution a dark blue/black colour.Titration continued at a slower rate until the solution had turned clear.Record the finishing titre mark on the burette.These steps were repeated 3 times for each time sample (total of 18 titrations).Figure 1 Diagram of titration in progress.6.0 ResultsTable 1 Table showing the amount of sodium thiosulfate solution added to sodium hypochlorite and potassium iodide solution at different times left under the UV ray.Refer to Appendix 2 for initial volume and final volume calculations and fair(a)s.Time (mins)Volume (mL)Average of 3 titrations023.351522.953022.516018.3518016.0324012.70Table 2 Table showing the concentration of pool chlorineRefer to appendix 3 for converting of average volume of titration to concentration.Amount of time left under UV lamp (mins)Concentration of OCl (M)00.03250150.03198300.03131600.025581800.022342400.01770Figure 1 graphical record showing the concentrations of pool chlorine left under a UV lamp for different periods of time.7.0 DiscussionAn experiment design was made to test and compare the effects of UV rays on pool environments, particularly on the impacts of chlorine concentration. In doing this, a total of 18 pool chlorine samples were deposit under a UV lamp for different periods of time. The concentrations of the chlorine when left untouched by UV rays were stable at around 0.03M. By exposing the pool chlorine samples to ultraviolet lights for habituated periods of time, the concentration of the chlorine decreased. The graph shows that as the sodium hypochlorite is more exposed to UV rays, the lower concentration of the pool chlorine was. A line of outstrip fit was drawn to display the trend in the data. It showed that there is a l inear relationship between the concentration and time left under a UV lamp. The data tranquil agrees with the theory that UV rays disrupt the structural integrity of the pool chlorine. The photodecomposition of chlorine is apparent as the initial levels of hypochlorite ion decreased by a significant amount when exposed to sunlight. The photochemical reaction that represents the situation of the experiment isThe main errors of the experiment were the inaccuracies of most aspects dealt with when implementing the experiment.One anomaly occurred when one sample of chlorine was left under the UV lamp for 60minutes. There is a major drop in concentration from 30min. This suggests that there was experimental error during the investigation.8.0 ConclusionThe results collected from this experiment suggest that the more pool chlorine is subject to UV lights, the lower the concentration of the chlorine will be. It has partially supported the hypothesisBibliography debutante Smith, D. R. (2006) . Chemistry in use Book 2. Sydney Queensland Chemistry syllabus.Date retrieved 05/09/12Fletcher, D. J. (N/D). (The Sodium Hypochlorite Story). Retrieved September 5, 2012, from south shore gunite pools http//www.southshoregunitepools.com/resources/htms/naocl.htmGina A. Ishida, B. . (N/D). IMPACT OF CHLORINE AND MONOCHLORAMINE ON ULTRAVIOLET. University of join Carolina, Chapel Hill, NC N/A.Date retrieved 05/09/12N/A. (N/D, N/D N/D). Chlorination of pool water. Retrieved September 6, 2012, from pested http//www.pested.msu.edu/resources/bulletins/pdf/2621/e2621chap7.pdfN/A. (1968). Stabiliser (Cyanurate) Use in outdoor(a) Swimming Pools. Retrieved September 5, 2012, from NSW Government Health http//www.health.nsw.gov.au/utilities/copyright.aspAppendicesAppendix AGoing to add MSDS laterAppendix 1Diluting sodium hypochlorite100mL of sodium hypochlorite was measured and put into a 1000mL volumetric flask.The flask was filled with distilled water up to the 1L markThe flask was inverted several timesSodium thiosulfate solution8.82g of sodium thiosulfate was placed into a 1L volumetric flashThe flask was filled with distilled water up to the 1L markThe flask was inverted several timesPotassium iodide solution5g of potassium iodide was weighed and placed into a 250mL beakerDistilled water was poured until it reached 105g on the scaleThe solution was thoroughly mixedStarch solution1g of starch indicator was weighed and placed into a 250mL beaker100mL of water was boiled and placed into the 250mL beakerThe solution was thoroughly mixed and was left to cool downAll solutions were labelled with the name of the solution, the concentration, a group members name and the teachers name.Appendix 2Initial volume and final volume of sodium thiosulfate left under a UV lamp at different periods of time.0 min 23.35-0.04 15 min 45.63-23.29 30min 22.34-0.07= 23.31mL =22.34mL =22.27mL46.76-23.31 23.04-0.14 44.78-22.32= 23.45mL =22.90mL =22.46mL23.54-0.13 46.66-23.04 23.01-0.21=23. 29mL =23.62mL =22.80mLAvg = = ==23.35mL =22.95mL =22.51mL60 min 41.22-23.01 3 hour 15.62-1.23 4hours 13.23-0.12=18.21mL =14.39mL =13.11mL18.62-0.33 30.59-15.62 26.35-13.23=18.29mL =14.97mL =13.12mL37.26-18.72 49.32-30.59 38.21-26.35=18.54mL =18.73mL =11.86mLAvg = ==18.35mL =16.03mL =12.70mL