化学英文化学报告Word格式文档下载.docx

1、 Calculate the Percent Yield of FerrateThe SpectraVis spectrometer was calibrated using DI water in full spectrum mode. The DI water was removed thoroughly using a plastic pipette and the sodium ferrate was put in its place. The absorbance of the sodium ferrate at 510nm was recorded; however, since

2、the value recorded did not meet the requirements, the solution was diluted until the value of the absorbance recorded at 510nm was beneath 1.5. When that level was reached, another sample of the solution was tested at 510nm and another value for the absorbance was recorded. The remainder of the solu

3、tion was placed in another beaker in preparation for the next phase of the experiment.The concentration of ferrate in the original solution was calculated using Beers Law.The two values for concentration were used by taking the average of the two to get the experimental yield of the ferrate. This va

4、lue of the experimental yield was compared to the theoretical yield that was calculated at the beginning of the experiment.Part 3: Performing the Reaction between Ferrate and DIatrizoicIn this part of the experiment, the goal was to perform the reaction of ferrate and DTZA to see how fast the reacti

5、on takes. The reaction was to be done two separate times and expected to be similar one to the other.In a first time, the SpectraVis spectrometer was calibrated using DI water. After the calibration the DI water was discarded in a waste beaker.Then 3mL of the sodium ferrate solution was poured into

6、a cuvette and a measure of the absorbance at 510nm was done. Similarly to the second part, if the absorbance value was above 1.5, the solution was diluted to get an appropriate absorbance value.The cuvette was thoroughly cleaned. Afterwards, 2.0mL of DTZA at 0.040M was acquired and 1.5mL of that sam

7、e solution was drawn with a pipette and poured into the cuvette.The next steps had to be done quickly in order to assure accurate results.1.5mL of the FeO42- was added to the cuvette and at that time a stopwatch was started. The absorbance was measured as soon as both solutions mixed in the cuvette.

8、 The cuvette was shaked for 5 seconds and placed in the spectrometer to measure absorbance. Every once in a while during 5 minutes worth of recording of the absorbance the cuvette was taken out and shaken. The measurements were done every 30 seconds during the 5 minute time frame. After the 5 minute

9、s were up, the ferrate-DTZA solution was discarded in the waste beaker and the cuvette rinsed out. The above was repeated for another trial with another combination of ferrate and DTZA identical to the previous one. The work area was then cleaned and a hypothesis formulated for the research part of

10、the experiment.Materials:20mL of Commercial BleachStirring BarStir Plate10g of NaOH pellets0.50mL of 0.30 FeCl3 solutionSuction Filtration apparatusGraduated cylinderGlass VialSpectraVis spectrometerPipettesCuvetteWaste beakerTest tube0.040 M DTZAPlastic bucketIceThermometerResults （Sara Furgeson） T

11、he theoretical yield of the reaction to create sodium ferrate using bleach, NaOH, and FeCl3 was calculated using the FeCl3 as the limiting reagent. As shown in the equation for the reaction, for every mole of FeCl3 used, one mole of sodium ferrate （Na2FeO4） would be produced.2 FeCl3 + 3 NaClO + 10 N

12、aOH 2 Na2FeO4 + 9 NaCl + 5 H2O The reaction used 0.50 mL of 0.30 M FeCl3, and the final amount of ferrate solution was 19mL. The theroretical yield was calculated to be 0.00769M.0.50 mL * 0.30 mol/L FeCl3 * 1L/1000mL = 0.00015mol0.00015mol / 19mL * 1000mL/L = 0.00789mol/L = 0.00789M Staring with 2.6

13、 mL of solution, 10mL of water was added to dilute it. Its absorbance at 510nm was 1.455, giving it a concentration of 0.001265M. Another sample had an absorbance of 1.192 at 510nm and a concentration of 0.001037M. Using the formula V1C1=V2C2 the original concentrations of the solutions were calcula

14、ted to be 0.00613M and 0.00502M. The average between them was 0.00558M. This was divided by the theoretical yield of 0.00789M giving a 70.7 percent yield. Calculating concentrations of samplesV1C1=V2C22.6mL * C1=12.6mL * 0.001265MC1= 0.00613M 2.6mL * C1=12.6mL * 0.001037MC1= 0.00502MAverage of two c

15、oncentrations（0.00613M + 0.00502M）/ 2 = 0.00558MCalculating the percent yield （0.00558M / 0.00789M） * 100% = 70.7% The reaction between those solutions of 00558M ferrate was timed as it reacted with DTZA. The absorbance was measured as the timed passed to calculate how fast the reaction was taking p

16、lace and how fast the concentration was changing. Then this experiment was repeated at different temperatures to see if lowering the temperature would slow down the reaction. The temperatures tested were 1, 4. 8, 12, and 16 degrees Celsius. All the rates of reaction were taken from Figures 3 through

17、 7 and compiled into Table 8 and Figure 8 for comparison.Trial 1:Time （s）ABS 510 nmFerrate Conc. （M）0.6310.000548696300.6560.000570435600.6740.000586087900.6220.0005408701200.6050.0005260871500.5830.0005069571800.5600.0004869572100.5520.0004800002400.5420.000471304270300Table 1: This table shows the

18、 differences in absorbance at 510nm and concentration as the time changes for the first trial of the reaction between ferrate and DTZA.Figure 1: This shows the first trial of timed reaction between ferrate and DTZA and the related equation.Trial 2:0.5890.0005121740.5780.0005026090.5790.0005034780.58

19、20.0005060870.5690.0004947830.5620.0004886960.5580.0004852170.5560.000483478Table 2: This table shows the differences in absorbance at 510nm and concentration as the time changes for the second trial of the reaction between ferrate and DTZA.Figure 2: This shows the second trial of timed reaction bet

20、ween ferrate and DTZA and the related equation.Reactions at 1 Degree Celsius0.8280.0007200000.8300.0007217390.8370.0007278260.7290.0006339130.7190.0006252170.6550.0005695650.6330.0005504350.6580.0005721740.6670.0005800000.6300.0005478260.6430.000559130Table 3: This shows the same reaction when the f

21、errate and DZTA started at 1 degree Celsius. As the reaction takes place, absorbance and concentration change with time.Figure 3: This shows the relationship between the time and the concentration when the reaction started at 1 degree Celsius.Reactions at 4 Degrees Celsius0.8670.0007539130.8680.0007

22、547830.8610.0007486960.8450.0007347830.8350.0007260870.8340.0007252170.8440.0007339130.8320.0007234780.8270.00071913Table 4: This shows the same reaction when the ferrate and DZTA started at 4 degrees Celsius. As the reaction takes place, absorbance and concentration change with time.Figure 4: This

23、shows the relationship between the time and the concentration when the reaction started at 4 degrees Celsius.Reactions at 8 Degrees Celsius0.9390.0008165220.810.0007043480.8050.00070.8090.0007034780.8160.0007095650.7930.0006895650.8220.0007147830.8120.0007060870.8060.00070087Table 5: This shows the

24、same reaction when the ferrate and DZTA started at 8 degrees Celsius. As the reaction takes place, absorbance and concentration change with time.Figure 5: This shows the relationship between the time and the concentration when the reaction started at 8 degrees Celsius.Reactions at 12 Degrees Celsius

25、0.6470.0005626090.6350.0005521740.910.0007913040.8470.0007365220.8170.0007104350.8390.0007295650.8020.0006973910.8070.0007017390.7760.0006747830.780.0006782610.8030.000698261Table 6: This shows the same reaction when the ferrate and DZTA started at 12 degrees Celsius. As the reaction takes place, ab

26、sorbance and concentration change with time.Figure 6: This shows the relationship between the time and the concentration when the reaction started at 12 degrees Celsius. The concentration at 0 and 30 seconds was lower than all of the following readings. There was probably some error, so these two times were ignored.Reactions at 16 Degrees Celsius0.7450.0006478260.7250.000630435