Beer’s Law Lab Report Essay

AbstractThe Beers law laboratory was conducted to take in the best wavelength of Co(NO3)26H2O with the use of spectrometry. The results determined that the optimum wavelength to film the hook onance of this brininess was 500nm. It also demonstrated how infection of baseless and absorbance of light be reciprocally proportional because absorbance is metrical by multiplying transmittal by a ostracize log. IntroductionWhen one is driveing chemical substances, there argon mevery valuable factors of significance. The blazon of a chemical is a useful similarlyl in its study. The light one sees produced by a chemical is the result of some(prenominal) reflection and absorbance of wavelengths. The wavelengths that are absorbed by a chemical are not visualized. The wavelengths that are reflected back are the colors that one sees. When chemicals are reduce in water, their colors also become diluted. As the chemical is diluted, the molecules spread apart. The more dilute the u pshot, the further apart the molecules. As the molecules spread, the color that is reflected becomes slight(prenominal) intense because some of the wavelengths are able to pass through with(predicate) and through the solving without encountering any of the solute.The more wavelengths that are able to pass through a etymon without encountering any of the solute, the greater the transmission. The transmittance can be mathematically reckon by dividing the amount of light that exited the solution (IT) by the amount of original intensity (IO). That value is then multiplied by one C to give the percent transmittance (%T)Beers Law is use to relate and compares the amount of light that has passed through something to the substances it has passed through. The Law is represented by A=abc. A is the absorbance of a solution. The a represents the absorption constant of the solution being stressed. The b represents the thickness of the solution in centimeters, and c represents the solutio ns molarity or concentration. The A can be cipher by using the negative log of the transmittance (T). The lab prove conducted used the salt Co(NO3)26H2O. The Co(NO3)26H2Owas diluted in distilled water to four unalike molarities. The most surd solution was used to determine the optimum wavelength to study the salt by measuring the transmittance of the Co(NO3)26H2O with xx different wavelengths of light. formerly the optimal wavelength was concluded, the transmittance of the less concentrated Co(NO3)26H2O solutions was also measured. The measurements of the less concentrated solutions was to determine the absorbance constant, a. Finally, the transmittance of an unknown concentration of Co(NO3)26H2O solution was measured and molarity was determined based on the absorbance constant determined prior in the experiment.ProcedureA run pipe was prepared with 0.1 M solution of Co(NO3)26H2O in 10mL of distilled water. half(a) of the .1M solution, 5mL, was drawn up into a pipette and fix up into another test pipage with 5mL of deionized water to make a 0.05 M solution. Half of the 0.05 M solution, 5mL was drawn into a pipette and raise into a test tube with 5mL of deionized water to make 0.025 M solution. Half of the 0.025 M solution, 5mL, was drawn into a pipette and put into a test tube with 5mL of deionized water to make 0.0125 M solution. A test tube of 10mL of deionized water was also prepared. The bubbles on all test tubes were removed by tapping on the outside of the test tube. The outside of the tubes were dried off and any fingerprints were removed with paper towels and placed into a test tube rack.An absorbance mass mass spectrometer was zeroed by measuring the transmittance at 400nm with no test tubes in the spectrometer. The spectrometer was then downd to degree Celsius percent transmittance with the test tube of deionized water. The deionized water was removed from the spectrometer and the 0.1 M solution was put inside the spectrometer. The transmittance of the solution was recorded and the solution was removed. The wavelength on the spectrometer was kindd to 410nm and the deionized water was placed back into the spectrometer and the transmittance was graduated to 100 percent.The deionized water was replaced with 0.1 M solution and the transmittance was recorded. This process was repeated twenty times with the wavelength increasing by 10nm consecutively until the last wavelength, 600nm, wasmeasured. It was necessary to calibrate the spectrometer mingled with each change in wavelength. Every change in nanometers had to be measured and calibrated at 100 percent with the control of deionized water. This maintained accuracy when the transmittance of Co(NO3)26H2O solutions measured.establish on the info gathered, the optimal wavelength was determined and the spectrometer was set to that wavelength. The transmittance was set to 100 with the deionized water. The 0.1 M solution replaced the deionized water in the spectrome ter chamber and the transmittance was recorded. This process was repeated with 0.05 M, 0.025 M, and 0.0125 M solutions and the transmittance was calibrated to 100 between each solution with the deionized water.Finally, a Co(NO3)26H2O solution with an unknown molarity was provided (unknown B). The wavelength of the spectrometer was not changed. The deionized water was placed in the chamber and calibrated to 100 percent transmittance. The deionized water was removed and replaced with a test tube containing unknown B. The transmittance was recorded to determine what the molarity was. informationAfter the solutions had been completed, the transmittance was measured at 10nm intervals from 400nm to 600nm. The measurements were determine the wavelength to best study Co(NO3)26H2O. Higher transmittance demonstrated less absorption of the wavelength and lower transmittance demonstrated full(prenominal)er absorption of the wavelength.DiscussionBeers Law is a law that demonstrates that the ab sorbance of light at a certain wavelength is directly proportional to the concentration or molarity of a solution. This was apparent with the naked eye. When do the solutions, 0.291 moles of was added to a test tube with 10mL of deionized water to make a 0.1 M solution. By taking 5mL out of the solution and mixing it with 5mL of deionized water, the number of moles was halved which make the second solution a 0.05 M solution. When the process had been repeated, it was apparent that the solutions had been diluted based on the color of the solutions in the test tubes. The 0.1 M solution was absorbing more light and was a deep rose color. As the solutions became more dilute, the concentration of the visible color diminished as less light was absorbed to a very pale translucent criticize in the 0.0125 M solution.For the first part of the lab, the wavelengths 400-600nm were used. These wavelengths were used to determine the optimal wavelength when the most light was absorbed by the solu tion. It was important to calibrate the transmittance to 100% on the spectrometer with the deionized water because there were no solutes to absorb light. The spectrometer was then able to use that calibration to determine how often of the light was absorbed by the solution containing Co(NO3)26H2O by comparing the residue in how much light was absorbed by the detectors in the spectrometer.The spectrometer than calculated the percent transmittance (%T) and displayed the data in a percent. As was shown above in gameboard 1 and graph 1, the %T started high and ended high with percentages over 90. The higher %T demonstrate less light was absorbed by the solution and therefore not the wavelength of light that is absorbed by Co(NO3)26H2O. Toward the middle of the data, 500nm and 510nm, the %T became substantially lower. This demonstrates that Co(NO3)26H2O absorbs wavelengths about 500nm.In the second part of the lab, the different molarity, or concentrations, of solution were measured f or %T with a 500nm wavelength. The absorbance was calculated by using the negative log of T. This was do because T and A are inversely proportional. This was demonstrated in table 2 and table 3. These tables confirmed that as T decreases, A increases.The trey part of the experiment used the point slope formula to determine a molarity based on an absorbance.The absorbance of light was dependent on the concentration of solute. The variables A and y are both dependent variables and were comparable to one another. The variable x and c were the independent variables. The variable a was the absorption constant and b was the thickness of the solution. In this case, b was fitted to 1 cm. Graphs 2 and 3 demonstrated the plotted points and from that, excel calculated a elan line based on the point-slope formula. Graph 3 demonstrated how the estimated molarity of unknown B, based on the point-slope formula, fits the trend line. ConclusionBeers Law was studied in this lab. The goals of thi s were to determine optimal wavelength absorption by Co(NO3)26H2O and determine transmittance and absorption from the data collected. The optimal wavelength absorption for Co(NO3)26H2O occurred at 500nm. The data also showed that while the transmittance and absorbance were indirectly proportional from one another, both variables were dependent on the concentration of the solution. at a time the data had been collected and understood, an unknown concentration of solution was tested for transmittance. Based on the trend line formed from other concentrations of Co(NO3)26H2O solutions, the molarity was substantially calculated to be 0.048.Possible errors that may go for occurred during this lab take in to do with calibration of the spectrometer. The transmittance values changed second to second so if the timing was not perfect in measuring the samples, the transmittance would mystify been erroneous. The transmittances would have been too high (based on experimentation) so the absor bance rates would have been too low. This in turn would have caused the absorbance constant to be too low. If the absorbance constant was too low, the concentration of unknown B would have been calculated too high.