Red #40 Simplified lab Report Fl 15 v2 (Responses) : Form Responses 1

1 | Timestamp | Last name , First name | Partners name | Chemical Symbol | Purpose | Summary | Procedure | Commentary | Lab section | I understand that I must send a copy of my final spreadsheet as a .pdf file to my instructor (ottmark@jccmi.edu) |
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2 | 10/7/2015 12:23:02 | Z,Han | A,Andrew | F | To determine the percent of red #40 in soda. | The answer of the C diluted is coming from 0.790-0.394. Following by the absorbance from 0.543-0.347. The slope of the red# 40 in soda is 60.27%, and the y-intercept is 10.73%, the Correlation is 97.54%. | Measure the 5-10g of red soda sample(undiluted), then diluted to 10ml and use the spectronmeter to calculate the Absorbance. Then use beer's law and CsVs=CdVd to calculate the Concentration of undiluted soda sample. For the second lab, the procedure is the same as the first lab. After the slope and y-intercept has been calculated. Use the slope as a Constant in Beer's law and y-intercept for correction to calculate the Concentration of diluted Faygo in the second lab | I think if we know the equation and procedure for the lab. The instructor has no need explain everything for one whole hour. Actually, During my observation after the lab . Everyone start to finish the lab at 45 mins. The pre-lab is actually awesome. But the whole lab paper is in a mess. The pre-lab have no need to change because in the lab calculation it is still the same as the pre-lab | T | yes |

3 | 10/6/2015 15:16:17 | G, Victoria | B, Alec | Be | To find the concentration of Red #40. | To find the concentration of Red #40. | We took samples of the Red #40 and put distilled water in it. Then we measured the mass of that substance and found the volume. After that we took that substance and measured the absorbency and with that we found the concentration. | The data seems to be reasonable because when we used the different amount of Red #40 we had close to the same amount of concentration. Error could have happened if we didn’t get every drop of Red #40 in there. We could have miss calculated more messed up our sells. | T | yes |

4 | 10/6/2015 20:15:58 | S, Rebecca | B, Chelsea | Cu | To determine the concentration of red #40 in Faygo red pop. | The concentration in Faygo red pop was found to be 6.80 mg/L. | Use the known stock solution and make four different solutions near it. Measure absorbancies and plot graph concentration versus absorbance to get equation of best fit line. Measure red pop sample. Dilute to 10.00 mL. Calculate the diluted samples. Determine the undiluted concentration from the absorbance and calculated measures. Calculate the slope, y-intercept, and equation with Beer’s Law | Compared to others the end calculations are reasonable. Other groups calculated 6.06 mg/L and 6.1mg/L, which are very close to the end calculation of 6.802 mg/L. Errors could be caused by other variables in the soda. If the cap is left open, excess water could have evaporated and caused different concentrations in different groups. The lab could be more effective if other variables in the red pop were accounted for. | T | yes |

5 | 10/7/2015 10:18:12 | D, Fatimata | B, Erik | Ba | To determine the concentration of Red #40 in a soda sample. | The concentration of Red #40 in a soda sample is 6.74 mg/L. | Five measured amounts of soda were diluted with water in a 10 ml flask. The mass of the solution and the given density of the soda were used to calculate the volume of the stock solution. To find the concentration of the diluted solution, the volume of the stock, the volume of the diluted solutions and also the concentration of the stock solution were used. A linear regression graph was created using the absorbance and concentration of the diluted solution. The concentration of the Red #40 was then calculated. | The concentration of Red #40 found was 6.74 mg/l. The data was very reasonable and comparable to another that got 6.69mg/l for the concentration of Red #40, these results are relatively close. The concentration of the stock solution and the concentration of the Dark Red#40 were very different from the concentration of the stock solution but that is because the stock solution was diluted quite a bit. However considering the fact that the results found while calculating the absorbance weren’t 100% accurate because the cuvet blocked some wavelengths from the solution, some errors could’ve been made. To make this lab a better learning experience, we should have a screencast included for all the prelabs. | T | yes |

6 | 10/7/2015 10:25:00 | T, Yashar | B, Noah | Dy | To determine the concentration of red#40 in Faygo Red Pop. | The concentration of red#40 was 6.69 mg/L. | A measured amount of Red #40 was diluted with water in a 10 mL flask to measure absorbance with the spectrometer. To find the volume of the solution, mass of stock and density of soda were used. Then to calculate the concentration of diluted soda, stock concentration, volume of solution and stock red #40 concentration were used. A graph and equation that shows liner regression of absorbance vs concentration of stock were created. The graph was used to find concentration of diluted Faygo soda. Using the Volume of Faygo red soda and concentration of diluted, the soda stock concentration was found. | In comparison to our concentration of stock, which was 6.69 mg/L, another group value was 6.73 mg/L which is similar. Some error might have occurred while testing a cuvette inside of spectrometer. Some lights might have been deflected while finding absorbance. To make this lab better learning experience, make the pre-lab more comprehensible and little bit in details, I had hard time to understating it. | T | yes |

7 | 10/7/2015 13:47:16 | C, Justin | B, Thomas | B | To determine the concentration of Red #40 in Faygo red pop. | The concentration of Red #40 in Faygo red pop was 6.34 mg/L. | The volumes of four stock solutions with a known stock concentration, were measured with a volumetric flask. The four stock solutions were then diluted with distilled water and the concentrations were calculated with a ‘dilution equation’ (CsVs=CdVd). The absorbance of each diluted solution was then measured using a spectrometer. The concentration and absorbance were then used to create a linear graph. The soda sample was then diluted using distilled water to find the absorbance of the diluted Red #40. The value found was then used in the Beer’s Law equation to configure the concentration. Finally, using the ‘dilution equation’, the concentration of the undiluted sample of Red #40 was calculated. | The concentration of undiluted Red #40 that another group found was 6.60mg/L. These concentrations were very close. The similar concentrations could be because of similar measures and calculations used to find the correct range of absorbance (0.300-0.600). Errors may have occurred due to other components that are a part of Faygo soda. Ingredients such as high fructose corn syrup affect the way in which the molecules interact. Interaction of corn syrup and red #40 may have affected the absorbance of light. A way to make this lab a better learning experience could be to give a more specific ratio for distilled water and stock solution so time doesn’t have to be wasted figuring it out. | T | yes |

8 | 10/7/2015 13:49:48 | B, Alec | B,Reed | Ag | The purpose of this experiment is to find the concentration of Red #40 in Faygo Red Pop. | The concentration of Red #40 in Faygo Red Pop is 6.60 mg/L. | Five solutions were made by diluting a stock solution in distilled water, each with slightly different absorbance levels and stock-to-distilled water ratios. Using a spectrometer and other various measurements, the light absorbance levels were obtained, along with the Red #40 concentrations of each solution, which was calculated by using the equation CsVs = CdVd . After plotting concentration vs absorbance on a scatter plot, a linear equation was generated. After diluting a sample of Faygo Red Pop in distilled water and obtaining the absorbance, the linear equation was then used to determine the concentration of said dilution. By using the CsVs = CdVd equation once more, the concentration of Red #40 in the non-diluted sample of Faygo Red Pop was determined. | There were similarities between the data found and the data of other groups. One group found the concentration of Red #40 to be 6.34 mg/L. Although there is a slight difference, it can be accounted for by the variations in dilutions of the stock solution. With variations in dilutions there will be a slight difference between the found values in the linear equations calculated. There may have been other errors that occurred, such as a slight shift in absorbance levels read by the spectrometer due to interference from the laboratory ceiling lights, causing the results from the linear equation to vary. In terms of creating a better learning experience, students should be taught a bit more about what Red #40 actually is and how it does or does not affect our bodies. This way, students could see the health effects of Red #40 from drinking excessive amounts of soda. | T | yes |

9 | 10/7/2015 14:05:19 | O,Madelynn | C Cody | Cr | The purpose of this experiment was to determine the concentration of undiluted red #40 in Faygo red pop using Beer’s Law. | The concentration in undiluted red #40 was 14.958 mg/L. | Absorbance of one concentration in Faygo red pop solution was measured. Then six different concentrations of stock were diluted to create six different diluted solutions using a volumetric flask. Absorbance was measured from these six different diluted solutions as well. Beer’s Law was used to calculate six concentrations of the diluted solutions. This data was used to generate a graph comparing absorbance with concentrations of diluted solutions. Then, the concentration of diluted red#40 in Faygo red pop and it’s absorbance was entered into the equation and the concentration of undiluted red#40 in Faygo red pop was calculated. | After comparing the results to other studies, our concentration stock was much smaller. The analysis of the concentration stock was 6.918 mg/L. Errors that may have occurred were the excess light passing through the absorbance calculation, creating a higher absorbance spectrum. Also the analytical balance may have accounted for any extra mass inside of it, in return throwing off our data. Something that could make this lab a more effective learning experience is trying to calculate density of the stock solution ourselves, making a separate column for it on our spreadsheet. | T | yes |

10 | 10/7/2015 15:39:36 | J, Kyle | C, Justin | C | To determine the concentration of Red #40 in Fay-go red pop. | The concentration of Red #40 in Fay-go red pop was determined to be 6.34 mg/L. | From a known concentration of stock solution, four separate solution samples were diluted to obtain varying concentrations of red #40. With the known density of the stock concentration, the mass of each sample was measured and both the mass and density values were used to calculate the volume of the four diluted solutions. After using a spectrometer to measure the absorbency of each sample, a scatter plot was graphed with concentration vs. absorbency in order to obtain a linear equation line. The absorbency of a diluted Fay-go red soda sample was then measured and used in the resultant line equation to calculate the concentration of the diluted sample. Using the Beer’s Law equation and the previously found values, the concentration of the stock Fay-go soda sample was determined. | The configuration of data was comparably similar to data from other groups that performed the experiment. Two other outcomes for the concentration were 6.29 mg/L and 6.09 mg/L. Some possible errors that could have occurred are that the stock sample solution we used was not exact with the density measurement, as well as the absorbency value from the spectrometer due to exterior light sources. For the future, it would be interesting to have a small list of different soda product samples (3-5) with given concentrations and have to determine which sample was which concentration and match it with the product name that closely matched each sample. | T | yes |

11 | 10/7/2015 16:59:24 | G, Kylie | C, Ryan | Br | To calculate the concentration of Red #40 in a sample of Faygo Redpop. | The concentration of Red #40 in the sample of Faygo Redpop was 6.92 mg/L. | Five different solutions of strong Red #40 concentration was diluted with distilled water until the solution reached 10 mL. These solutions were then measured for absorbency through a spectrometer, aiming for an absorbency ranging from 0.3 to 0.6. The concentration of the diluted solution (Cd) was then found by using the dilute equation CsVs=CdVd (Cd=(CsVs)/Vd). The absorbency vs. Cd of all five solutions were then graphed using Beer’s Law. A linear equation was formed from the graph. A sample of Faygo Redpop was then measured and diluted to an absorbency ranging from 0.05 to 1.0. The absorbency of the sample of Faygo Redpop was plugged into the linear equation in order to solve for the concentration of the diluted Faygo Redpop. The dilute equation could then be used to find the value of Cs (concentration of Faygo Redpop). | In comparison with other group’s data, the values were not far off. One group had a result of 6.29 mg/L while another group had 6.16 mg/L. One possible reason why the values were not exactly the same could be because water evaporation may have taken place if a student forgot to replace the lid on the stock solution or the soda or. For a better learning experience, it would be interesting to know some background information on Beer’s Law. For example, why is it that when the absorbency of Faygo Redpop is plugged into the Beer’s Law equation, the result is the concentration of Red #40 in the soda? We are told that absorbance is directly proportional to the concentration but knowing how this equation came about would result in better understanding of the lab as a whole. | T | yes |

12 | 10/7/2015 17:09:02 | S, Melanie | D, Fatimata | Na | To determine the concentration of red #40 in a soda sample | The concentration of red #40 in the soda is 6.095. | Found the density of the solution at various dilutions. Used a spectrometer to measure the darkness of a colored solution by how much light passes through it. Determined red # 40 concentration. | The information for setting up the spreadsheet seemed scattered and was hear to understand | W | yes |

13 | 10/7/2015 18:19:26 | S, Dylan | G Alex | N | In this experiment the concentration of red #40 in a soda sample will be calculated. | The recorded concentration of red #40 in the soda sample was 6.25 mg/L. | A sample solution with a concentration of 1.429 mg/L was diluted into a 10.00 mL flask to calculate the diluted concentration. The diluted solution was placed in a cuvette to calculate the absorbance by a spectrometer. This test was done 6 times to calculate an average slope and Y intercept to make an equation for the concentration to absorbance. The soda was too concentrated so it was diluted and checked for absorbance. With the absorbance, the concentration of the diluted soda was measured which helped to calculate the concentration of the undiluted soda. | Other groups had concentrations of 6.50, 6.10, and 6.15 mg/L which is right around the 6.25 mg/L. Mistakes may have came up when stirring up the solution and the water because sometimes the solution was already filled up too much where it was hard to stir it in the flask. The first 2 paragraphs in the lab description seem a little repetitive when talking about the lab because in the third paragraph it actually shows what is happening and the first 2 paragraphs may not be needed. | W | yes |

14 | 10/7/2015 18:59:06 | C Cody | G, Kylie | Ar | To determine the concentration of undiluted solution of Red # 40. | The concentration of undiluted Red #40 is 13.02 mg/L. | Use an unknown concentration stock solution to make several different ones. then measure absorbance of the solution from the first step then plot the concentration versus absorbance and get equation of resultant line. Then measure the absorbance of the soda solution, if too concentrated dilute it until it achieves a measurable absorbance. From absorbance found for the soda sample and equation found in earlier steps determine the concentration of the color in the unknown sample. Knowing the volumes used in step 2, calculate the concentration of the original soda sample made in the second step | The final result for the lab was 13.02 mg/L, this was alot higher then other groups. They had from 6.60 to 5.00 mg/L. though the equations were the same the information used was different. The ability to know all of the substances in Red #40 that could affect the results could be helpful in the future labs. | T | yes |

15 | 10/7/2015 19:09:04 | W, Leslie | G, Victoria | Er | Find the concentration in Red #40 solution. | The determined concentration of Red #40 in Faygo red pop was 3.52 mg/L. | Multiple diluted solutions created by distilled water composed of approximately 10 m/L of Faygo red pop and water to create a lighter color then, the mass and volume of each solution was calculated. Once the solution was made the absorbance needed to be found. The solution was poured into a cuvette and then placed into the spectrometer. The concentration was then measured/calculated by using the absorbance and volume of the diluted solution. Lastly there was a graph that was used to show the data (absorbance and concentration) was linear. | The data that was collected gave an r^2 value of about 87%. Most groups got the concentration to be about 6.0 mg/L. There was some error in a concentration of 3.52 mg/L. This error may have occurred because the volume of each solution wasn’t exact before putting into the spectrometer which would have given better results for absorbance. Had the lab equipment been cleaned before each trial the lab and results would have been better. | T | yes |

16 | 10/7/2015 20:28:06 | B, Chelsea | H, McKenzie | Al | The purpose of the experiment was to determine the concentration of red #40 in Faygo Red Pop using Beer's Law. | The concentration of red #40 in Faygo Red Pop was determined to be 9.06 mg/L. | Five weighed samples of stock solution were diluted and their absorbencies found using a spectrometer. Using the mass, density, and absorbencies of the stock solutions the volume and concentration were calculated using Beer's Law and then put into the graph to get absorbance vs. concentration. The was used to find the slope of the line 0.513, the y- intercept 0.539, and the correlation 0.994. Finally, a Red Faygo Pop sample was taken and diluted to find the absorbency and volume of the original and diluted sample of Faygo Red Pop. We used Beer's Law to determine the concentration of both the original and diluted samples of Faygo Red Pop. | Another group found that the concentration of Faygo Red Pop was 6.91 mg/L, with a 2.15 mg/L difference from my group who got 9.06mg/L. The data appears to be correct because the absorbencies only varied by 2.15mg/L. The error was probably caused from not measuring or weighing the solutions completely correct. | T | yes |

17 | 10/7/2015 20:42:53 | M, Daniel | Hs, Aaron | Cl | The purpose was to find the concentration of red #40 in Faygo Red Pop. | The concentration of Faygo Red Pop was 6.29 mg/L. | Five samples of stock red #40 solution were diluted at different amounts. Using the volume and concentration of red #40 solution and the volume of diluted solution, the diluted concentration was calculated. The absorbance of each solution was measured in a spectrometer, and these data were used with the diluted concentrations to create a linear regression. A sample of Faygo Red Pop was diluted and measured to find its absorbance. This absorbance was used with the linear regression to calculate the diluted concentration of Faygo. With the volume and concentration of diluted Faygo and the volume of Faygo prior to dilution, the concentration of red #40 in Faygo Red Pop was calculated. | The results of this lab are reasonable when compared to the results of other groups. Others obtained concentrations such as 6.92, 6.69, 6.35, and 3.95 mg/L. Since the concentration of red #40 is near the average of others’ data, it appears to be reasonable. Error in measurements is due to slight variation in the analytical balance, the spectrometer, and when lining up the meniscus in the volumetric flask. Error could also be caused by other additives in Faygo Red Pop that may affect how much light it absorbs. To improve this experiment, the absorption of these additional ingredients could be measured and used to adjust the actual absorbance of red #40 in red pop. This would produce a more accurate concentration and provide a more intensive learning experience. | T | yes |

18 | 10/7/2015 20:53:16 | B, Noah | I, Azeez | He | The purpose of the lab is to determine the concentration of red#40 in Faygo Red Pop. | The concentration of red #40 in Faygo Red Pop is 6.09 mg/L | Take 5 stock solutions and dilute them (using Beer's Law equation) to an acceptable absorbency for the spectrometer. Once all absorbency values are acceptable graph them with the concentration values. Measure out an amount of diluted soda that will give you an acceptable absorption. With that absorbency plug it into the equation of the trend line found earlier to find the concentration of the diluted solution. Use that number in the Beer's Law equation and solve for the Undiluted Concentration. | No group in the lab has the same final answer; one being 6.46 and one being 6.19. The difference could be made where our correlation coefficient differs greatly. It would help teach the content of the lab a little more if there was more hands on work with the spectrometer. We kind of just dropped the liquid in and wrote down the value. If there were multiple set up around the room, and we had to adjust them ourselves we would get more out of it. | W | yes |

19 | 10/7/2015 21:01:44 | W, Mark | J, Kyle | Eu | Determine what the concentration of red #40 is in Faygo Redpop. | The concentration of red #40 in Faygo Redpop is 5.95mg/L. | Find the mass of each sample of undiluted solution of water and red #40. Use that to find the volume and then dilute it with water until a total of 10mL is in a volumetric flask. Use that solution in the spectrometer to find absorbancy of a specific wavelength of light. Five different solutions were made and used. One run of Faygo Redpop was done and the absorbancy measured was used to find of the concentration of red #40 in redpop alone. | Although I am colorblind and that may affect my own perception of the intensity of color of the solutions, the Redpop was considerably darker in color than the known solution samples. Another group got 6.29mg/L for the concentration in Redpop and that is within an acceptable range of our result. | T | yes |

20 | 10/7/2015 22:08:01 | L, Rick | K, Jason | Kr | To determine the concentration of Red # 40 within undiluted soda. (Faygo Red Pop) | The concentration of Red # 40 within the soda sample was determined to be 2.151 g/mL. | Five solutions of Red # 40 dyed water were created, each with the same concentration of Red # 40 (1.009g/mL). Using various instruments to measure mass, and a spectrometer to measure absorbancy, the concentration of each solution was calculated. After plotting the absorbancy vs. concentration of each solution on a scatter plot, a linear equation was obtained. After determining the absorbance of the soda sample, the linear equation was used to determine the concentration of Red # 40 within the stock soda. | The data configured seemed to mismatch other groups. One group had a concentration calculation of 2.151 g/mL, while other groups results seemed to be much larger. The cause of this difference must be due to human error. Other factors could have altered the results also. Overall cleanliness of equipment and unknown substances within the soda could have altered the absorbancy of the soda, in addition to effecting the density of the soda. Thus rendering overall calculation flawed. Perhaps more trials used with properly cleaned equipment would have fixed this error. | W | yes |

21 | 10/7/2015 23:01:16 | M,Hannah | K, Jay | Co | This lab was performed to determine the concentration of red #40 in a soda sample. | The concentration of red #40 in the stock soda was 6.29 mg/L. | From a known concentration of stock soda solution, four solutions of different soda to distilled water ratios were created and their absorbency was measured using the spectrometer. After obtaining the results from the stock solution, the absorbency of a darker, red colored soda needed to be calculated. This data was obtained by finding the mass of the red soda, diluting it with distilled water, then finding the absorbency with the spectrometer. Using Beer's Law, the concentration of the undiluted stock sample was able to be calculated and a concentration vs. absorbance graph was made. | All absorbencies were between 0.536 and 0.772, with a correlation of 0.996, which is strongly correlated. The concentration of the red #40 in the stock soda was 6.29 mg/L, which is comparable to another group's final reading of 6.09 mg/L. Variations in concentration could be due to differences in ratio of soda to distilled water chosen, not enough samples made, and samples made outside acceptable absorbency range. | T | yes |

22 | 10/8/2015 12:13:15 | B,Reed | L, Rick | Gd | This lab is performed to find the exact concentration of red #40. | There was a standard deviation from the eight diluted runs of .97. From that data, the actual concentration of red#40 was determined to be 6.17 mg/L. | Eight deviations of the red#40 were diluted to different absorbency levels and measured. This data was then put together to create an equation which was then applied to use given data of red#40 and calculate the concentration of the pure substance. | This number of 6.17 mg/L seems very accurate as it was fairly close to other groups' numbers: 6.15 mg/L and 6.5 mg/L. Some possible room for error in the calculations is the fact that the test was not done in completely dark room, which thusly could alter the actual absorbency of the diluted samples. There was a little confusion in the way this lab sheet was put together (somewhat scattered) so a more organized lab explanation could have helped. | W | yes |

23 | 10/8/2015 14:35:58 | S, Brock | M, Ariel | O | To determine the concentration of red #40 in a sample of Faygo Red Pop using Beer’s law. | The concentration of red #40 in Faygo Red Pop was calculated to be 6.146 mg/L. | In this experiment, samples of a stock solution containing red # 40 were diluted so that their absorbancies could be read by a spectrometer. The concentration of dye in the diluted solutions were then calculated and a graph was created comparing the concentrations with the solutions’ absorbance readings. A sample of Faygo Red Pop was then diluted and its absorbance readings taken. Using the absorbance reading and the trend information from the graph, the concentration of red #40 in the diluted soda sample was calculated. This information was then used to calculate the red #40 concentration of the original soda sample. | The results of this experiment are comparable to others that yielded values of 6.3 and 6.17 mg/L. Possible cause of error could be that when the spectrometer was zeroed, there was a different amount of light in the room than when we did the experiment. The source of the change could be the amount of daylight shining through the windows by the door. A way this experiment could be improved is by remaking the screencast. The screencast discusses the calculations without the context of the experiment. The experiment is described afterwards. Previous screencasts went through the experiment and explained the calculations when that part of the experiment was reached. This format helped put the experiment into perspective. | W | yes |

24 | 10/8/2015 14:53:49 | B, Erik | M, Daniel | H | To determine the concentration of red #40 in a soda sample. | The concentration of red #40 in the soda sample was 6.248 mg/L | A small amount of soda, our stock solution, is poured into a beaker and weighed to determine the mass of the soda in the beaker. Using the known mass and density, a volume is calculated. The soda is then diluted with distilled water to 10 mL and the concentration is measured for absorptivity. The beaker is now filled with another soda sample, which has a known concentration and density. The volume is calculated. Using the known concentration of the soda and the known volumes, the concentration of the diluted soda sample is calculated. After diluting the concentration to 10 mL, absorptivity is now calculated. This is done 4 to 5 more times to create a varied data set. The data is graphed, using absorptivity and diluted concentration of the samples. Using this graph it is possible to calculate the concentration of the diluted soda sample. Using the known diluted concentration, the equation CdVd=CsVs is used.. From this the Cs of the unknown sample is determined. | Our group had very similar results to that of other groups, examples being 6.149 mg/L and 6.346 mg/L. This suggests that human error may be at fault. Imprecision of the human eye in determining of exact volumes of the diluted soda may skew results slightly, but not enough to cause huge margins in error, thus leading to small differences in data between groups. The layout of the lab worksheet was cluttered and could have been better organized. The diagram could have smaller, allowing for better spacing on the text and creating an easier to follow procedure and pre-lab setup | W | yes |

25 | 10/8/2015 16:12:49 | Me, Brandon | M, Katherine | Li | To determine the concentration of Red #40 in Faygo Red pop. | The concentration of Red #40 in the Faygo Red pop was 6.50 mg/L. | A solution of known concentration containing Red #40 was diluted into six solutions which were calculated to contain red #40 concentrations of various amounts. Their absorptions were measured using a spectrometer. A graph representing their absorption versus concentration was created and was used to create an equation to solve for absorption given a concentration. A sample of Faygo Red pop containing red #40 was diluted and absorption was measured to give the diluted concentration. Using the Volume of the Red pop before it was diluted, the volume of the diluted Red pop, and the concentration of Red #40 of the diluted Red pop, the concentration of Red #40 in the original sample of Red pop was then calculated. | Data calculated was 6.50 mg/L. Data calculated by various other groups were 6.25 mg/L , 6.29 mg/L, 6.45 mg/L. The data calculated compared to others was close. Variations in data could have been caused by errors from the spectrometer. The spectrometer was used in an environment flooded with light which could cause the absorption to be off. The density of the Red pop was an average of a class’s data collected on the Red pop a couple of years ago. As time passed water could have evaporated causing the density to change. The fact that it is an average means that some of data collected on the experiment could be off and throw off the actual density of the Red pop as well. The lab document could be change to help improve comprehension of the lab beforehand if it was included that all the measurements of volume would be measured with a volumetric flask. The minor detail would help make the connection, using higher order thinking, that one is measuring mass into the volumetric flask then adding water to that to dilute it to 50ml. From the current wording it sounds like one is possibly using a graduated cylinder from when it is referenced that volume from a graduated is not all that accurate. It could also alleviate the confusion and that you are not using a cuvette to measure volume. | W | yes |

26 | 10/8/2015 17:08:39 | Y, Izabella | M,Hannah | Rb | To determine the concentration of red #40 in a soda sample using Beer's law. | The concentration of red #40 was determined to be 3.630 mg/L. | Small samples were taken from a stock solution and their concentrations and absorbance were found. A graph was made to plot concentration versus absorbance and the equation of the resultant line was found. Then, a soda sample solution was diluted and the absorbance was measured. From the absorbance and the equation found in the graph, the concentration of the soda sample was calculated. Once the concentration was found, it was used to calculate the concentration of red #40 in the undiluted soda sample solution. | The concentration of red#40 found in the lab did not compare to the concentrations found in others' labs. They were getting numbers like 6.3 mg/L and 6.1 mg/L, while the lab we conducted gave a measurement of 3.630 mg/L. It would seem that one of our concentration was over 1.000 mg/L which may have screwed with the way the rest of the lab played out. When describing Beer's law to us, I don't think it is necessary to explain the constant, since it will be found in the graph in the form of y=mx+b. It is not something that was used in the lab and just made me confused while setting up my spreadsheet because I kept thinking I needed to figure it out. I also heard other people complaining about the same thing. You could just explain that graph will be used to determine the diluted concentration with the slope and y-axis of the graph, without mentioning the constant. | W | yes |

27 | 10/8/2015 19:40:09 | M, Katherine | Me, Brandon | La | The concentration of red #40 in a soda sample was determined using Beer’s law. | The concentration of red #40 in the undiluted soda was determined using Beer’s law. This concentration is 6.252 mg/L. | The mass and absorbance of one 10 mL solution of soda and water were found. The mass and absorbance were used to find the volume of the stock solution, red #40 concentration in diluted soda, the red #40 concentration in undiluted soda, the slope, and the y-intercept. The mass and absorbance of five 10 mL solutions of red #40 and water were found, keeping the absorbance data for these samples between .05 and 1.0 for the Beer’s law graph. The volume of the stock solution and the concentration of the diluted stock sample were calculated using the mass, absorbance, density, and concentration of the stock sample. The absorbance and concentration of the diluted stock solution were graphed to calculate the r squared value, the y-intercept, and the slope. | The data is reasonable because the r squared value is .998 and our concentration value was similar to several other groups’ data. Some other groups’ concentration values were 6.203, 6.305, and 6.235. The lab document was very wordy and descriptive so it was somewhat difficult to understand. It made a lot more since after hearing the explanation from the instructor. | W | yes |

28 | 10/8/2015 21:32:03 | G Alex | O,Madelynn | K | The purpose of this experiment is to determine the concentration of red#40 dye in a sample of faygo redpop using the beer’s law, and the dilution equation. | The concentration of red #40 dye in the soda sample was 6.29 mg/L. | In the experiment the raw data gathering consisted of first taking a ‘stock’ solution of red dye #40 with a known concentration and density measuring out a certain amount then diluting it with water then measured the light absorbance of it, this is done a total of five times. Then this data was constructed into a graph to determine the relationship between absorbance and concentration and found the equation of the linear relationship. Lastly the mass was measured of a sample of faygo redpop then diluted with water, next the absorbance of it was taken and with the equation from the graph the concentration of the diluted soda sample was determined then with that the dilution equation was used to determine the concentration of the undiluted soda sample. | This data is reasonable because in comparison with other analyses they are fairly similar, the concentration of red dye #40 in this sample came out to be 6.29 mg/L, where other analyses concentration of red dye #40 in soda sample ranged from 6.169-6.248 mg/L. A source of error could be not taking into account the other ingredients in the soda which may affect its light absorbancy. One thing that could be beneficial for the lab is maybe take a small amount of time at the very end when all the experiments are finished, and have a discussion/reflection time about the lab techniques and if they are improving or not for each individual and why/why not. | W | yes |

29 | 10/8/2015 22:03:20 | W, Ciara | R, Ariel | Pd | The purpose of the lab was to determine the concentration of red #40 in a soda sample using Beer’s Law. | The concentration for the soda was 10.42. | To find the absorbance vs. The Concentration of Diluted Red pop. Take a reasonable amount of the solution and then dilute it to what will give an absorbance level between 0.05 and 1. After the results are found for that, do trials on a colored substance (red #40) to find the same things; anywhere from five to eight trials. This will give a linear relationship between the concentration and absorbance of the data. With the graph the concentration of the diluted soda were found and with that the undiluted concentration of soda was found. | Comparing the data found of 10.42 to Dylan Shaw’s group whose was 6.25 for the concentration of undiluted soda it is very different. The numbers are different because of an error. The error could be looked at as a personal error or an error in the wording of the lab handout. The lab could have been more effective by giving us a range of masses. The numbers of the five trials were kept between 1.0 and 2.0 grams because the lab print out did not say a range of masses to reach. This caused the data to be very different from others participating in the lab. | W | yes |

30 | 10/8/2015 22:29:23 | V Jacob | S, Bram | P | The purpose of this lab is to determine the concentration of the red #40 of the diluted sample and the concentration of the undiluted soda. | The concentration of the red #40 of the diluted sample was 1.22 mg/L and the concentration of the undiluted soda was 6.16 mg/L. | In this lab, five solutions were made using a stock solution, but all containing a different starting mass. These solutions were then diluted to 10.00 mL and the resulting diluted solution was placed in a spectrometer to measure its absorbance. To then find the concentration of the diluted solution (Cd), the dilution equation was used after the rearranging of the variables. The Cd value was then graphed against the absorbances to find the y-intercept and slope, which were then used as the constants in Beer’s Law. Beer’s Law was used, along with the found absorbance, in the trial with the soda solution to find the concentration of the diluted soda. Finally, the dilution equation was used one more time to find the concentration of the undiluted soda sample. | The data collected in this lab was accurate because the concentrations found by other groups were 6.29 mg/L and 6.92 mg/L, which is in the range of 6.16 mg/L. One possible reason that these values could have been different is because evaporation could have occurred in the time that the lid was not on the stock or soda container, or the previous students may have forgotten to put the lid back on. Another reason that the values could have differed is because there is a possibility that a different type of water was used to dilute the solutions. To make this a more effective learning experience during the three-hour lab period, the background information on Beer’s Law and the dilution equation could have been enhanced. Although the dilution equation was pretty easily understood, Beer’s law could have been explained in more depth because the derivation of the equation would have been helpful in the understanding of the concept as a whole. Also, some of the busy work of repeating the processes multiple time could have been cut down by having the groups share their data amongst each other so that the math and plugging in of values could have been focused on more closely, the process of what goes where. | W | yes |

31 | 10/9/2015 0:05:07 | SSpencer | S, Brock | Mo | Determining the concentration of red #40 in a soda sample using Beer's law. | The concentration of undiluted soda obtained is 6.17% | Faygo redpop was inserted into a 10 mL volumetric flask, mass measured, then diluted with water. Using Beer’s Law obtained revealed the Concentration of diluted redpop and using an spectrometer obtained Absorbance. Using a graph and the absorbance, the spreadsheet reported the Absorbance Diluted and finally the concentration of undiluted soda 6.17%. | Compared to other group numbers of 6.15%, 6.5%, 6.24%, and 10.42% the number received from the spreadsheet seems decently close to what the number should be. When doing this lab the screencast explained Beers law and Dilution Equation, however it didnt relate to how the lab was going to work so it was really confusing and made building a flowchart really difficult. | W | yes |

32 | 10/9/2015 0:13:59 | C, Ryan | S, Dylan | I | To determine the concentration of #Red40 in a soda sample. | The result of our analysis for the concentration of the soda was 10.42 | The first step is to take a sample of red pop and find an absorbency that is between .05 and 1, you do this by diluting it with distilled water. Once you find this you will use this as a target area, for 5 to 8 trials of a colored substance (Red#40). Using the data collected you can then use the graph to find the relationship between the two, allowing you to find the concentration of red#40 in a soda sample. | Another group that I talked to received a concentration of the diluted soda, 6.25. This is significantly lower than what I came up with. A possible error could have been that our data we collected was not as close to the soda sample we first took, so that left a lot of wiggle room for a more precise answer. 2. Although Doc.Ott already talked about the importance of the lab calculation flowchart, I think this is really important for this lab in particular. This lab was very confusing on where to start. If I had a better understanding of what information I need to get, then the procedure of actually "doing" the lab wouldn't have been as confusing. | W | yes |

33 | 10/9/2015 0:43:27 | A,Andrew | S, Ian | Ga | Determine the concentration of red #40 in a soda sample using Beer's law. | With a mass of 1.5160(g) and the concentration of the diluted solution .9232 we were able to determine the concentration of red#40 in soda as 6.346 | Solutions of a liquid with a known density were taken and diluted down to get their absorbency and concentration values. With these values a graph is created to establish an equation for concentration vs. absorbency. The absorbency of a diluted solution of pop was taken and the concentration found by using the graph. With the concentration of diluted solution solved the concentration of red#40 in an undiluted solution was found. | The number I got for red#40 in soda(6.346) was close to other groups answers. Other answers 6.505,6.095,6.246,and 6.452 suggest that my measured value is accurate. A possible sources of error in this experiment was not diluting the solutions enough to get an accurate absorbency value. A way to make this a more effective learning experience would be to have students dilute the soda first to see the range of values to aim for in Phase 1 of the lab, and have students as a class zero out the spectrometer | W | yes |

34 | 10/9/2015 1:04:31 | B, Thomas | S, Melanie | Ho | The experiment is asking for the concentration of Red #40 in a sample of soda using Beer’s Law. | The concentration of the undiluted sample of Red #40 in the sample of soda is 6.29 mg/L. | To start the experiment, get a sample of soda and take the mass. Dilute the sample to the right ratio so it reads between certain values on the spectrometer, which gives the absorbency. Then make 5-7 solutions of varying concentrations to get absorbencies of the range of the spectrometer. Make a graph to show the relationship of concentration and absorbency. Calculate the concentration of the undiluted soda. | The data acquired is the concentration of the undiluted soda sample. They are sound because the data is very comparable to other group’s final answers. Most of which are about a tenth or so off. An addition that would help students understand the lab would be for the Instructor to tell the students a general idea of what the dilution needs to be on the soda sample. It took multiple samples of soda to be able to have the right absorbency, which is wasteful of the limited resources that the lab provides. | W | yes |

35 | 10/9/2015 1:13:22 | R, Ariel | S, Rebecca | Mg | Determine the concentration of red 40# in Faygo Red Pop using Beer’s Law. | The concentration of red 40# in the Faygo Red Pop sample was 6.25 mg/L. | Five samples of a known concentration were weighed and the volume was found using the known density. They were then diluted with water to 10.00 mL, and concentration was calculated using the dilution equation. The results were graphed to get the equation for Concentration vs Absorption. The procedure before the graph was repeated with a Faygo Red Pop sample, and initial concentration was found using the equation. | Alex Gust’s group’s value was 6.29 mg/L, which was 0.04 mg/L off from my groups, so it looks like our data may be accurate if we got about the same results. how imporve ok - meo | W | yes |

36 | 10/9/2015 1:46:43 | K, Jason | SSpencer | CA | The purpose in this lab was to determine the amount of red#40 in a sample of soda that is too dark to be read by a spectrometer using dilution. | The final result we got was .1039, indicating that the amount of red#40 in the stock sample to be that value. | The procedure for this lab was to first weigh the mass of the empty flask, then find out the mass of the soda minus the weight of the beaker. After this, we dilute the solution, then measure it in a spectrometer to determine the absorbancy. After plenty of samples have been collected, a graph is plotted, and a line equation is formed. From this, we can subtract absorbancy from our R2 value, divided by the slope to calculate the red#40 in the diluted sample. We can then multiply the diluted concentration of the solution divided by our stock volume to obtain the final number | I feel as though some error was made in our steps, because our data does not compare well to other group's- such as Ariel Miller's group, who got 0.9760 for their final result. There may have been confusion towards the beginning regarding the calculations over density, mass, and volume that could have easily thrown our group's data off if not payed careful attention to.I believe that calculating mass during the pre-lab could have made this gone more smoothly. | T | yes |

37 | 10/9/2015 3:51:27 | K, Jay | T, Yashar | Se | To find the concentration of red #40 in Faygo™ Redpop. | The concentration of red #40 in Faygo™ Redpop is 6.37 mg/L. | The volume (mL) of a stock solution of known concentration was calculated by measuring the mass (g) of the solution in a weighted volumetric flask and the known density (g/mL) of the stock solution. The volumetric flask was filled to a volume of 10.00 (mL) and the concentration of red #40 in the diluted solution (mg/L) was calculated. The absorption of the diluted concentration was then found by using a spectrometer. Beer’s Law Plot was created using the absorption and concentration of red #40 (mg/L). The equation was then used to determine the concentration of red #40 (mg/L) in a diluted sample of Faygo™ Redpop. The concentration of red #40 (mg/L) in an undiluted sample of Faygo™ Redpop was then calculated. | The data received from others seems to be somewhat consistent with that of which I received. One group had concentration of red #40 in an undiluted sample of Faygo™ Redpop of 5.647 (mg/L). The results are very reasonable, but one reason in which they could be different is the correlation value. The higher the correlation value between the gathered data of concentration of diluted sample (mg/L) and absorption of the sample solution would result in more accurate data gathered when calculating the soda sample. The correlation value I had was above .993 and the other groups was .866 possibly resulting in less accurate data leading to the slight differences between the concentration of red #40 (mg/L) in an undiluted sample of Faygo™ Redpop. I think it would benefit to have the lab document reflect how we did the experiment in Lab. To find the absorbance of the soda sample first and then use the sample solution to get data close to that absorbance seems much more accurate. Doing it this way it's much easier to get a higher correlation value, thus reflecting more accurate data when calculation the concentration of red #40 (mg/L) in an undiluted sample of Faygo™ Redpop. | R | yes |

38 | 10/9/2015 11:59:29 | H, McKenzie | V Jacob | RU | Determine the concentration of Red #40 in Faygo Red Pop. | The concentration of Red # 40 in Faygo Red Pop was determined to be 1.453 mg/L. | Varying amounts of Faygo Red Pop were diluted to 10 mL. The concentration of each solution was found using the dilution equation and the absorbance for each was found using a spectrometer. A known mass of undiluted soda was diluted and the concentration and absorption were found. Using the dilution equation, the concentration of Red #40 in Faygo Red Pop was determined. | Compared to other groups (1.433, 1.526) our concentration seems acceptable. Significant sources of error would be water droplets on the side of the cuvette scattering a separate beam of light and altering the absorbance. In order to make the lab more efficient, what if there were a way to combine all of our ‘runs’ into one by starting with the soda sample in the cuvette and adding water until certain absorbances were reached. | R | yes |

39 | 10/9/2015 12:16:34 | M, Ariel | V, Kayla | Si | To determine the concentration of red #40 in a specific soda sample. | The concentration of red #40 in the soda stock solution was 0.9760 mg/L. | A sample of soda was measured and then diluted to a specific constant amount. The solution was then mixed and placed in a Spectrometer to get the absorbency of the solution. Several other solutions were made, but with concentration of a specific substance (red #40). The same procedure was taken and then a graph was made with the absorbency and diluted concentrations. With the volumes from the unknown solutions, then the calculation was made for the undiluted soda sample. | Our data was relatively reliable, because we had seven samples of solutions and we had numbers that fell both above and under the y intercept. Another group had a concentration of the stock as 0.1039 mg/L. Our data also had a trend line with the data very relative to that line, with our correlation coefficient being 0.999 which is extremely close to 1.0, in which it could not go over. | R | yes |

40 | 10/9/2015 16:54:06 | W, Keith | V, Samuel | Xe | What is the concentration of Red #40 in a soda sample? | The concentration of Red #40 in the soda sample was 6.37 mg/L. With .994 correlation coefficient. | Took the soda sample and diluted it to measure it's absorbency for a base line. Then from a known stock concentration solution several different ones were made. Their absorbency's were measured and then plotted against concentration creating a Beer's law plot. The plot is then used to find the concentration of the dilute. The dilute equation is then used to find the concentration of the soda sample. | I feel like the data was reasonable because there was too much Red #40 in the soda and you could still see through it. In the experiment we got a concentration of 6.37 mg/L while Ian's group got 4.07 mg/L. This difference could be due to the oil on our fingers being transferred on to the cuvettes. The Red #40 could have settled in the soda sample or the known concentration sample. A few things that could that might make the experiment more accurate are wearing unpowered rubber gloves and stirring both the solution and soda before taking sample. | R | yes |

41 | 10/9/2015 15:01:19 | I, Azeez | W, Ciara | Sc | The purpose was to determine the concentration of the red #40 in Faygo red pop. | The concentration of Faygo red pop was 7.33 mg/L | Targeting the absorbance data in the range of 0.05 to 1.0, mass of stock was weighed in 6 runs and Volumes of the stock were calculated using the known density of the stock solution. With the known concentration of stock solution and known volume of diluted soda, concentration of diluted solution was calculated using dilution equation (CsVs=CdVd). Each absorbency were measured using a spectrometer. Then a graph of Absorbency vs Concentration of the solution was plotted and a linear equation was obtained. Also absorbency of the soda was measured. The linear equation and absorbency of soda led to the value of concentration of the diluted solution (using beer's law). Mass of the soda was measured, and volume of soda was calculated with the known density of soda,. With this value, and the values of Absorbance, concentration of diluted solution and known volume of diluted solution, the concentration of red #40 in the soda was calculated using the dilution equation. | The data seemed to be in line with other people's data which were between 7 and 8 mg/L-- one group had 7.61mg/L and another had 7.05mg/L. These data are reasonably close to each other and can be considered good data. Possible error might be due to the fluctuation of the spectrometer. Perhaps, wiping the weighing scale before using it could reduce error in mass measurement as there might be some drops of solution in the scale. | R | yes |

42 | 10/9/2015 17:34:06 | S, Bram | W, Henry | Tc | To determine the concentration (mg/L) of red#40 in an undiluted soda sample. | The concentration of red#40 in an undiluted soda sample was determined to be 5.65mg/L. | Six solutions were placed in a flask, their volumes were calculated using a mass-density equation. Each was diluted, to a constant volume. A sample was removed from the diluted solution and its absorbance was measured using a spectrometer. Constants were provided for the density of both the soda and solution, as well as the concentration for undiluted solution. After plotting the data on a graph relating concentration and absorbance, a linear equation was produced. The equation was used to solve for the concentration of a diluted soda sample. Using Beer's Law, the concentration of red#40 was determined in an undiluted soda sample. | The data gathered was similar to one group and different from another’s data. One group determined a concentration of undiluted soda sample at 6.37mg/L while the other calculated a 1.453mg/L concentration. Possible errors; mislabeled constants of density and concentration on the containers of soda and solution samples. An uncalibrated spectrometer can lead to inaccurate absorbance values. Both errors can immediately offset our data and cause inaccurate results. Perhaps, a real demonstration of how to measure and obtain the volume of solution and soda samples could be shown before starting the lab. This will alleviate confusion as to how to obtain the solution volume. Also, sharing a Google spreadsheet with all Thursday lab student's email would assist in comparing data to other groups for the 'commentary' section of the report. | R | yes |

43 | 10/9/2015 17:46:34 | W, Sadie | W, Keith | Y | To determine the concentration of Red #40 in a soda sample using Beer’s Law. | The diluted concentration of the soda was determined to be 0.299 mg/L, the undiluted concentration of the soda was calculated at 1.453 mg/L, and the absorbency of the solution was determined by the spectrometer to be 0.431. | A sample of soda was diluted to 10.00 mL and tested for absorbency by a spectrometer. From a stock solution, several other solutions were made and diluted to 10.00 mL in a volumetric flask, concentration was calculated for each. Absorbency was tested in a spectrometer (required range was between 0.05 and 1.0) and recorded to create a scatter plot of the absorbency vs. the concentration. From the collected data, the concentration of Red #40 in the undiluted soda sample was calculated. | The data collected can be determined as reasonable based on several factors. One of the solutions used had a volume of 9.233 mL, and the concentration was measured at 1.342 mg/L. The concentration of the soda sample was calculated at 1.453 mg/L, since the solutions were made in a 10.00 mL volumetric flask, it would make sense for these two concentrations to be close in value. Also, the R2 value for this data was 0.99, suggesting that the collected values are of reasonable range. The data that was used to compare (Bram Siemers data) showed an undiluted value of 5.65 mg/L. This is far from the value calculated by McKenzie and myself, however the compared data also had an R2 value of 0.866, suggesting that the data may not be in acceptable range. Improvements on this experiment could be made in explaining how to obtain acceptable absorbency values. This could be considered common knowledge however this was the only issue encountered in mine and my partner’s experience, not understanding how much soda it would take to reach an acceptable absorbency. | R | yes |

44 | 10/9/2015 18:13:08 | V, Kayla | W, Leslie | Te | To determine the concentration of red #40 in a Faygo Red Pop sample. | The concentration of red #40 in the soda was found to be 5.699 mg/L. | A diluted sample of Faygo Red Pop was made using distilled water and the absorbance was discovered using a spectrometer. Seven diluted solutions from the stock solution and distilled water were then created. Using the dilution equation and the known concentration of the stock solution the concentrations of the 7 solutions were able to be calculated. Using those concentrations as well as the absorbance calculated by the spectrometer a linear graph was made correlating that information. The equation from the linear graph was used to find the concentration of the diluted Faygo sample created earlier, from that using the dilution equation once more the concentration of red #40 in the stock red pop was obtained. | Our group determined that the concentration of red #40 in the red pop sample to be 5.699 mg/L where as another group determined the concentration to be 7.33 mg/L Although the numbers are relatively close ours was low. The error could be from a malfunction of our dropper that wasn't properly expelling water in drop form or from spilling some of the diluted soda from the volumetric flask it may not have been thoroughly mixed when it spilled. This lab was simple in procedure, I do believe that writing a rough procedure prior to lab would increase the understanding needed and make the lab smoother overall. | R | yes |

45 | 10/9/2015 20:31:54 | Hs, Aaron | W, Mark | S | Numbers for the data are good. Graph points surround the point trying to be calculated. Reasonable results, had to heavily dilute the soda, so a high concentration of red#40 was expected. The lab itself ran smoothly, though giving faux data in the pre-lab involving the calculation from mass - volume using density may make them more prepared for the lab, or so they don't have to code the cell after the lab period has started. | R | yes | |||

46 | 10/13/2015 13:19:48 | S, Ian | W, Sadie | Tb | To determine the Concentration of Red #40 in Faygo Red pop | The concentration of Red #40 in the pure soda sample was determined to be 4.70g/ml. R^2 was 0.997 | A sample of pure soda was diluted then its absorbency was measured. several other solutions were then made using a known mass of stock solution, then diluted with distilled water. The absorbency of these solutions were then measured. Using Beer's law the concentration of the diluted solutions, and their absorbency, were plotted. Using the Y-int, and slope of the graph, the concentration of red #40 in the pure soda sample could be calculated. | The concentration of red #40 in the adjacent groups were between 6 g/ml and 9 g/ml, while we calculated it to be 4.71 g/ml. The varying of our results could be attributed to the low mass of the stock solution used in many of our diluted solutions, or a small amount of residue left on the plastic container used to measure absorbency. To achieve a greater level of accuracy we could have used a more accurate system of measuring the volume of each solution. | R | yes |

47 | 10/9/2015 21:34:26 | V, Samuel | Y, Izabella | Ti | Calculate the concentration of Red #40 in a red soda. | The concentration of Red #40 in a red soda was determined to be 6.50 mg/L. | The red soda sample is diluted and its absorbance is calculated with a spectrometer. Samples from a stock solution with known concentrations are weighed and using the density of the solution a volume is obtained. The concentrations of these samples are found using the 'dilution equation' before being diluted. The diluted samples are put in the spectrometer to find their absorbances using the soda sample's absorbance as a target. A graph is created using absorbance as the dependent y-variable and concentration as the independent x-variable. From this graph's trendline the concentration of the diluted soda solution is interpolated. After this it is possible to calculate the undiluted soda concentration using the 'dilution equation'. | All in all the lab, procedure, and lab document are both well thought out and effective in their uses. A possible change to the lab that may make it slightly more accurate is to run more than one test to find the concentration of diluted red soda. The average of these tests could be used in the calculation for the undiluted red soda. This addition may prove to be more tedious than useful. I reviewed my spreadsheet with Aaron Higgins when we found that our final concentrations were very different. He calculated the final concentration to be 7.67 and I found mine to be 4.35. After reviewing our sheets we found that I had used the density of the stock solution in my dilution equation as opposed to the given concentration. Henry, my lab partner, will not know about this because I failed to get his contact info after the lab and I haven't sat with him yet. | R | yes |

48 | 10/9/2015 21:42:20 | W, Henry | Z,Han | V | Determine the concentration of red #40 in a soda sample using Beer's Law. | Concentration of red #40 soda sample is 4.35 mg/L. | Six solutions of red soda samples were weighed, each with a different concentration. Solutions went through a spectrometer, given the absorbance. After plotting Absorbance vs Concentration Stock, this demonstrated a linear relationship. Concentration of red #40 in a soda sample was determined by using Beer's Law from experimental data and calculations. | The concentration of red #40 soda sample from our experiment was 4.35mg/L. In relation, another group derived at 6.92mg/L which is a significant difference. Possible error could be due to the absorbance from not properly drying the glassware when inserting into the spectrometer. To improve learning experience, introduce the purpose of dilution preferably where it can be used so this experiment could be insightful for the future. | R | yes |