Water analysis

Students argon tried and true for their knowledge of elemental titration technique and proper usage of unique(p red-faced-facedicate)- make use of try outs (those utilize for conduction, alkalinity, and pH, chloride, nitrate and awkwardness detection) on Logger Pro tardilyw be. The purpose of this encyclopaedic testing ground is to determine the chemical properties of common tipsiness pee found at cardinal detail locations in the Toledo Ohio atomic number 18a.Students test the unhomogeneous repertories of this crapulence urine by subjecting it to the avocation tests pH tests, conductivity tests, tally and phenolphthalein alkalinity tests, essential sturdyness, chloride tests, and nitrates tests. With respect to the selective information pl tart In this lab, students in wish well manner use conversion factors to omen the parts per million. quest directions carefully and prudently Is crucial for the success of the experiment and as rise up to the fact that the scrutiny will be finished during the lab period.Tests the like these are perform daily by industrial irrigate manipulation plant in order to ensure the Toledo such(prenominal)(prenominal) the EPA to report its findings in spite of appearance a written deadline. Obviously reports of pee system quality that are non up to the governments mensurations, (all of the modulars will be listed at a later segmentation in the report) will be subjected to further testing and isolated from public entranceway until the well-worns are met.This lab mimics the daily routines of employed chemists at these facilities on a smaller scale. Students that chose to enter such profession will be held responsible for using the techniques learned in this lab. Safety Information closely of the chemicals utilise in this lab are dangerous. Avoid bodily contact, ingestion or any type of spills. Assume that all of the reagents utilise in the lab are poisonous.Rinse the pH try out thoroughly with distilled water. Place the essay into a small beaker that contains cardinal of the two monetary standardization buffer dissolvents. B. remove Experiment, set , and select the Sensor Setup tab. With the button for Port 1 (or Channel CHI) depressed, confirm or choose the Sensor pH see and Calibration PH. Select the Calibrate tab and click on Calibrate Now. C. Gently stir the buffer with the pH investigate. When the voltage reading of the pH essay is stable. Enter the pH nurture of the buffer solution (read discharge of the bottle of buffer solution) to the nearest 0. 01 intoValue 1 and press Keep. D. Rinse the probe with Del water and thence place it in a small beaker that contains the arcminute calibration solution. When the reading is stable, enter the pH stand out by of the buffer solution to the nearest 0. 01 into Value 2 and press Keep. Press K to retentivity the calibration. E. Check that the calibration worked by placing the probe back into the buffer sol ution. If the displayed measure does non match the judge of the buffer, exit out of Logger and clear up the window. The displayed probe in pH 7 buffer until it is later necessary. 4. ) buzz off a commensurate size of render to determine the PH. Ml is suitable for this experiment. Measure this list of seek using a graduated cylinder. dispatch the examine also ml glass beaker. 5. ) Place the pH probe into the beaker containing the sample. participate the pH of the sample on your Data mainsheet. 6. ) Rinse the probe with Del water and dry it. Immediately place the probe back into the pH buffer. conduction Test 1 . ) The experiment should already be open on the laptop. If non, select the Expo. 14 Conductivity icon that is on the desktop. 2. ) forked check that the switch box is set to 0-Phipps/CM. This corresponds to 0-magma/L TTS ( get along Dissolved Solids).If necessary, you may change this setting to match your samples value. A high range standard is visible(pre nominal) if needed. 3. ) Calibrate the conductivity probe using a two- maculation calibration. Use the low-and mid-range solutions to perform the calibrations. A. Initiate the calibration role in the software b. Place the Conductivity Probe into a standard solution with a low conductivity value (this should be between O IPPP/CM or O- MGM/L TTS Say 1 moms/CM). Be sure the intact elongated hole with the electrode waxs is submerged in the solution ND that at that place are no air bubbles along the electrode surface.Wait for the displayed voltage to stabilize. C. Enter the value of the standard solution in the appropriately chosen units. D. Repeat the calibration using the medium conductivity (this is between O Phipps Say mount/CM) 4. ) Analyze the samples conductivity a. Using a rinsed ml graduated cylinder, pulse ml of the sample. B. transpose this amount to anther houseclean and dry beaker. C. Place the probe into the beaker containing the sample. D. Wait for the reading t o stabilize. Record the conductivity on your data sheet. E. transform the reading into MGM/L and panderer. Source Conductivity Probe, Fernier Software and Technology via their website www. Fernier. Com/ funding/manuals/) match and Phenolphthalein Alkalinity Tests 1 . ) Measure 50 ml of your sample in a graduated cylinder. Transfer the sample into a mall rafttrical flask. 2. ) Add terce to five drops of phenolphthalein solution to you sample. 3. ) Set up a titration apparatus (where the clean buret is clamped too ring stand). 4. ) produce to the highest degree mall of sulfuric superman (HASPS) into a larger beaker. 5. ) Full the burette with HASPS up until a point above the calibration mark (Mol).Place a waste beaker under the burette. diffuse the stopcock and release the remaining HASPS to swallow rid of air bubbles. 6. ) Record the exact concentration of the HASPS into your data sheet. Record the sign burette reading to the nearest 0. 01 ml. Replace the waste beaker w ith the flask containing the sample. 7. ) Titrate the sample too discolour slight depot. The solution will be barely pink Just forrader the endpoint of the solution. Add a few drops of 10% tessellate solution to the sample (do this Just before the endpoint of your titration ) Record the final volume of the HASPS used. A.Use the mixed indicant brochures unfledged/methyl red) this sample should be green at the beginning and the endpoint should be a lily-livered-straw colourize. B. If needed, refill the burette with to a greater extent HASPS. Record the initial value into your data table. sample distribution will become color puny and then the next drop should make up you the straw color. 8. ) Record the phenolphthalein alkalinity and bestow alkalinity in militarily and supply. Total abrasiveness Test 1 . ) Obtain ml of your water sample measured on a graduated cylinder. Transfer the sample too mall volumetric flask. 2. ) Add one assume of Universe indicator to your sampl e.The color of the solution should be reddish pink. 3. ) Obtain bout mall of bon motion. Record the concentration of your iterant. 4. ) Set up a similar titration thingy. Rinse a burette with Del and then with transaction. 5. ) Fill the burette with enactment up until the calibration mark. Place the waste beaker under the burette. Open the stopcock to remove air bubbles. Record the initial volume of DEED on your data sheet to the nearest 0. 01 ml. 6. ) Titrate the sample until the color of the solution changes to light blue. 7. ) Report the total big(a)ness in militarily and procure. (Other Sources Water Chemistry, ANAL ERROR, Kippering, Edith.CHEMICAL Lab Manual. 2013-2014) Results pH and POOH determine per individually sample tried Total alkalinity and phenolphthalein alkalinity Carbonate, hydrated oxide, or bicarbonate alkalinity amaze? Carbonate, Hydroxide, and or enthalpy carbonate alkalinity Total Hardness and Non-Carbonate strongness of each sample Nitrates/Chlo rides face Conductivity tests per each sample model Calculation used in savor 4 pH Value collected from pH probe 6. 42 pH H+ = (1. Owe-14)/ (3. 8+7) = 2. 6+8 M POOH = -logOH- = -log(2. E-8) = 7. 58 Total alkalinity When a 100. 0 ml sample is titrated with 0. 010 M HCI, 0. ml acid is the equivalent of 1. 0 paramour cacao tree ( origination). Total Volume of acid titrated (for both phenolphthalein and brochures green methyl red indicators) 5. 21 ml 0. Ml acid/l . 0 pimp cacao -? 5. 21 ml acid/ x pimp Cacao 52. 1 pimp cacao Phenolphthalein alkalinity *Due to a shortage in the amount of sample available for immediate testing just now ml was used for the titration using phenolphthalein indicator. The calculations below are triad-fold in order to compensate for variables used in the proportion) * of 1. 0 pimp Cacao (source). Volume of acid titrated 1. 51 ml 2(o. Ml pimp cacao) = 2(1. 51 ml acid)/xx 5. pimp cacao Carbonate Alkalinity Present? Carbonate alkalinity is present when phenolphthalein alkalinity is not zero, but is less than half(prenominal) of the total alkalinity (source). Half of Total alkalinity = 15. 1/2 = 26. 05 pimp cacaos o 15. 1 pimp cacaos 26. 05 pimp cacao Yes carbonate alkalinity is present because the phenolphthalein value (15. 1 pimp Cacao) is a nonzero number that is less than half of the total alkalinity of the sample (26. 05 pimp Cacao). Carbonate Alkalinity Carbonate alkalinity = 2 (phenolphthalein alkalinity) = 2(15. 1) pimp (CO)2- = 30. 2 pimp (cacao)2- Anton Hydroxide Alkalinity Present?Hydroxide alkalinity is present if phenolphthalein alkalinity is more than half of the total alkalinity. 15. 1 pimp cacaos 226. 05 pimp cacaos This statement is bogus thereby proving that no hydrated oxide alkalinity is present in this sample of water. Hydroxide alkalinity N/A hydrogen carbonate Alkalinity Present? Bicarbonate alkalinity is present if phenolphthalein is less than half of the total alkalinity (source). 15. 1 pimp Cacao 26. 0 5 pimp Cacao Yes bicarbonate alkalinity is present in this sample because the phenolphthalein alkalinity value (15. 1 pimp Cacao) is less than half of the total alkalinity of the sample 26. 5 pimp Cacao). Bicarbonate Alkalinity Bicarbonate Alkalinity = T-UP = 21. 9 pimp HCI- Total Hardness of Sample When a 100. 0 ml sample is titrated with 0. MM DEED, 0. 10 ml of DEED is the equivalent of 1. 0 pimp Cacao (Kippering, Lab Manual). *Due too shortage in the amount of sample available for immediate testing only ml was used for the titration using phenolphthalein indicator. The calculations below are doubled in order to compensate for variables used in the proportion) * Volume of DEED titrated 5. 25 ml 2(0. 1 ml pimp cacao) = 2(5. 25 ml DEED)/XX pimp cacao x = 52. 5 pimpNon-Carbonate hardness of the Sample This is the difference between the Total Hardness and the Total Alkalinity (52. 5 pimp cacao) (52. 1 pimp cacao) = 0. 4 pimp cacao Observations Each of the four-spot samples collected were visually similar. Each were colorless, and mostly free of suspended particles. no(prenominal) exhibited any odors. The test through on sample 4 for hardness were dissimilar to the tests through with(p) on the previous samples because it form an orange tortuous with the Universe indicator rather than the more commonly found red color. This may have been due to improper cleaning of glassware.The phenolphthalein alkalinity test done for sample 3 was peculiar in that do-gooder of large amounts of iterant did not produce a visible endpoint. Upon further investigative assistance from the TA it was confirmed that the water sample was already at its most virulent state recognizable by the phenolphthalein indicator. Discussion The purpose of this lab was to dissemble the government-run procedures done to analyze public boozing water, an important event that is mandated by the Environmental Protection Agency (EPA). Understanding the underlying methods for success at these series of experiments is what the main idea is.The series requires students to recall and implement various laboratory techniques in order to process the sample of water. It is a comprehensive review on the following using computer software such as Logger Pro, calibration technique using various specific probes, titration, understanding the prefatorials of geochemistry in chemical expressions, understanding the do of pH on solutions, and overall safety awareness. Chemists use these techniques to tackle more thickening problems. For now, the simpler mint experiments listed above are up for discussion. The first experiment done was the total hardness test.This involves the iterant, DEED which forms a dark red mazy with the indicator Universe. Adding this iterant to the sample-indicator mixture causes the red color to fade. This is the result of the unknown surface action in the sample reacting with the DEED and getting rid of the red complex formed. indeed the solution color twines bl ue, which signals the student that the endpoint has been reached. canonicalally the amount of DEED titrated determines the amount of unknown metal present in the sample. These metals are Ca+ and Approximation of the specific action present is hard reliant upon the pH of the ample water.If the pH is above 12, then only the Ca+ action mass be detected. The total hardness of sample 1 was reported at 119. 9 pimp Cacao. The extent to how hard the water is, is de distinguishd by a scale of water hardness. The scale used here was taken from the Fairfax County Water Authority, a water treatment facility. It states that soft water has less than 17. 1 pimp of metal particles, slightly hard water has 17. 1 60 pimp metal particles, hard water has 120-one hundred eighty pimp metal particles, and very hard water has over 180 pimp metal ions present (Explanation of Water Hardness, www. Face. G The water in sample 1 is therefore moderately hard to hard. Sample 2, 3, and 4 contain slightly hard water. In addition the Non- carbonate hardness was also calculated. The results from both the total and non-carbonate hardness tests for each sample are shown in the graph titled, Total Hardness and Non-carbonate Hardness of each sample. The non-carbonate hardness tests accounts for different anions other than the carbonates that may be responsible the presence of dissolved salts in drinking water. Such anions admit certain types of sulfates, chlorides, and nitrates (Kippering, Lab Manual).The non-carbonate hardness of each sample cannot be persistent until a full assessment of the total alkalinity of each sample is done. hence these calculations are held for the third section of this paper. The EPA does not have a standard or hardness of water. In fact, the National Research Council states that hard drinking water oecumenicly contributes a small amount of calcium and milligram human dietary needs (Explanation of Water Hardness, www. Face. Org). How can we tell what ions are p resent in each sample? This is only dependent on the relative pH of the samples which is discussed in the next section.Determining the pH of all four samples is a simple procedure. As long as the pH probe is calibrated using the correct buffers each function should give an accurate result. PH is a measure of the concentration of protons (H+) in a sample. Solutions containing large exponentially small concentration of hydrogen ion give a large value pH and the opposite is true for high concentrations. This phenomenon occurs because measurement of pH is measured on a logarithmic scale. The pH set given by the computer can be born-again into hydrogen ion concentrations by taking the negative log of the pH of the sample.Chemists use the ion- product of water theory to convert hydrogen ion concentration to hydroxide ion (OH-) concentration. Simple use the equation K = HUH+ *H+ and HUH+ can be used interchangeably Using these equations students can effortlessly convert the pH of thei r samples into their equivalent hydroxide concentrations as noted in the graph titled, pH and POOH value per each sample tested, The pH of sample 1 is 5. 5, which is highly acidic. Sample 2 has a pH of 6. 02. Sample 3 has a pH of 6. 49, whereas sample 4 has a pH of 6. 42 all of the samples tested here contained slightly acidic eater.The EPA does not have a standard for pH because it is considered a heartbeatary drinking water contaminant, which is aesthetic (pH, www. Odd. Ohio. Gob). Although the EPA does not regulate this property of water, the Ohio Department of Health does forget additional causes and effects of unnatural pH levels. They claim that the our water, the soil composition that the surface water runs though and a host of others (pH, www. Odd. Ohio. Gob). These causes are most relevant as they have a direct impact on the quality of our drinking water, which comes primarily from surface waters.As a result from continued use of basic water (pH above 7) people report bi tter tasting water, and buildup of minerals in plumbing (pH, www. Odd. Ohio. Gob). As a result from continued use of acidic water, residents will have sour tasting water, and metallic staining (pH, www. Odd. Ohio. Gob). intense cases will undoubtedly cause bodily harm Just as the reagent used in lab. As stated earlier, both calcium and milligram ions can be detected in samples at a pH lower than 12. Since all of the tested sample have lower pH set, we can conclude that there are both calcium and atomic number 12 ions present.The following experiment tested each sample for total and phenolphthalein alkalinity. Alkalinity is a measure f the amount of basic ions in a sample (Kippering, Lab Manual). The procedure for alkalinity is titration. Students find the phenolphthalein alkalinity first by titrating the sample with the phenolphthalein indicator to a clear endpoint and recording the amount of iterant (HCI) used. A second indicator, (brochures green methyl red) is added to the sam ple and further titrated to a straw yellow color. Students use the amount of HCI added in the first titration to calculate the phenolphthalein alkalinity.Then they use the total amount of HCI titrated to calculate the total alkalinity. The following expression was used to calculate all of the entries for total and phenolphthalein alkalinity when a 100. 0 ml sample is titrated with 0. 010 M HCI, 0. 10 ml acid is the equivalent of 1. 0 pimp Cacao (Kippering, Lab Manual). Each calculation can be seen in the graphs titled, Total alkalinity and Phenolphthalein alkalinity. All of the measurements are calculated in pimp Cacao. Sample 1 produced a phenolphthalein alkalinity of pimp Cacao and a total alkalinity of 181 pimp Cacao.Sample 2 reduced a phenolphthalein alkalinity of O pimp Cacao and a total alkalinity of 18. 9 pimp Cacao Sample three gave a phenolphthalein alkalinity of 10 pimp Cacao and a total alkalinity of 54 pimp Cacao. at last Sample 4 gave a phenolphthalein alkalinity of 15 . 1 pimp Cacao and a total alkalinity of 52. 1 pimp Cacao. In addition to these two measurements, students were also required to calculate the carbonate, hydroxide, and bicarbonate alkalinity if at all present in the samples. The results table for these variables are found under the table titled, Carbonate, Hydroxide, or Bicarbonate alkalinity present?If the samples met a certain criteria, then they tested positive for the three possible alkalinitys. Students could then use the three equations listed in their procedure and calculations sheet to calculate the alkalinity of the corresponding anion present. A trend can be note in the tables above. Samples that had no hydroxide alkalinity tested positive for carbonate and bicarbonate alkalinity respectively. Samples 3 and 4 both shared carbonate and bicarbonate alkalinity. Thus sources of carbonate solids are the main ratifiers to their alkalinity. Sample 1 is the only one that is positive for hydroxide alkalinity.Thus salts of hydroxid e essential be the main contributor to its alkalinity. PH and alkalinity are treated similarly by the EPA, as they are both regarded as secondary standards. They are not regulated. In general alkalinity is treated much the same as basic solutions are. Total alkalinity is needed to calculate the non-carbonate hardness. Now the values for total alkalinity done. Students simply subtract the total hardness by the total alkalinity. The values given show the amount of dissolved solids that are not carbonates (such as sulfate, nitrate and chloride salts). The last three tests are the most simple.They involve the usage of specific probes Just as in the experiment for pH determination. The next experiment tested the conductivity of the four samples. Conductivity is a measurement of electrical activity in a sample. After proper calibration of the software, students place the conductivity probe into the sample and enter the value on the data sheet. The standard value of water conductivity is given in as/CM. All of the entries for the four samples are located under the table titled, Conductivity tests per each sample, Distilled water has a conductivity of about 0. as/CM to 3 as/CM whereas many rivers along the U. S. Have conductivities as large as 50 to 1500 as/CM (Conductivity, water. EPA. Gob). The results from the four samples tested show that the drinking water in the Toledo area is much similar to that of the water in all of the U. S. Waterways. The high voltage could be due to the dense cosmos of dissolved ions present in each sample. Such quantities could produce a small electrical gradient. The very last two experiments were Just like the last experiment. This time students tested their sample for nitrates and chlorides present.A nitrate-specific probe was seed for the nitrate analysis and the chloride specific probe was used or the chloride analysis. After mightily calibrating the probes, students immersed the probes into each sample at a time and collected th e data displayed on the computer. The entries for these two experiments are located below the table titled, Nitrates/Chlorides present. Each value is expressed using the standard units of MGM/L. According to the Ohio EPA, the standard amount or nitrates in public water is MGM/L (Water fictional character Standards Program, www. EPA. Tate. Oh. Us). A value high than this standard violates he sanctions set forth by the EPA and leads to further investigation of the problematic water. Each of the four samples had a value much less than the standard, proving that the public drinking water from the Toledo are is partially free from nitrates. Why are nitrates so bad? We must look way back to the original source of our drinking water- surface water. Surface waters from rivers and lakes can easily become tainted with contaminants such as pesticides, wastes, and fertilizers (rich in nitrates).Although presence of nitrate to us may not be a bad thing to us, it most certainly is to the envir onment. sudden increase in such nutrient bound runoff causes extremum algal blooms consume large amounts of oxygen in the water. This in turn suffocates aquatic organisms. And pesticide in our drinking water obviously poses as a health concern. The maximum amount of chloride allowed in public drinking water is OMG/L according to the United States EPA (Basic Information about Disinfectants in Drinking Water Chlorine, Chlorine and Chlorine Dioxide,water. Pa. Gob). All four samples abide by this regulatory standard. If the opposite had occurred the government would shut off the publics access to this eater. The chloride ion is very reactive, so in nature it is usually found accustomed to a group IA or AAA metal or to itself. By itself it can become dangerous. Error Analysis The probability of human flaw for this series of experiment is multiplied due to Mistakes were undoubtedly made solutions were over-titrated, and probes were used that were not calibrated properly.One such exampl e of human error is the source of the large difference between sample Xis total alkalinity compared to the other three samples. This is a sign that a student over-titrated the solution. This exults in a volume of hydrochloric acid titrated that is larger than the actual value needed. Thus alkalinity value is higher because the calculation shows that a larger amount of acid was needed to countermine the water sample. It gives the false impression that the sample was very alkaline/basic to begin with.To fix this, students should add iterant by the ml until resistance to color change takes longer, then add drop wise. Calibration of the probes was always an issue. Although the samples tested positive for the standards governed by the Environmental Protection agency, the results from the conductivity tests were a little high. Thus to FL this problem, he probes must be properly calibrate. To properly calibrate a probe means to immerse he sensitive judgement into the solution (so the sma ll white dot is Just below the unstable surface) and enter the value of the corresponding standard into the computer.The one step that catches mot students is the waiting time. Impatience lead to improper calibration. Cross contamination of the probes by dipping them in the samples without cleaning them with denizen water and wiping them off with a clean towel could also have adversely affected the results from the experiment. Misinterpreting he values displayed on measurement instruments such as the graduated cylinder and the values on the computer could have led to tremendous error. Misuse of probatory figures was a drawback caused by both the student and the computer.This applies mostly to the calculation of hydrogen ions and hydroxide ions from pH values. The computer at lab showed pH values using both two one and two significant figures. ageless rounding up of number during calculations ay have alter the actual value of the hydroxide concentration slightly. Conclusion The pu rpose of this series of experiment was to provide students a real-life application of nearly all of the techniques they have learned in their first year of general chemistry lab.The concept of the entire procedure was to show student how certain chemical species (like dissolved actions, anion, and organisms perhaps) interact in aqueous solution. The results from the series of experiments show that the various techniques used in college lab are similar to the ones used by employed chemists in water treatment plant. Wheres the proof? Well by looking at the results from this lab and comparing them to the standards produced by the Environmental Protection Agency, one could say that they are quite similar.