Molarity Analysis

With these absorbance numbers a concentration curve was constructed and the unknown solution was determined by finding the point of absorbance on the curve.

3ml of sample was taken first flask at 4 minutes and added to the appropriate tube of sodium hydroxide, from the second flask at 4.5 minute and so on, each flask was sampled at 30 second intervals. The sampling was then repeated starting at 8,12,16 minutes. The final sample from the last flask was taken at 18.5 minutes. Once the sampling was completed, measurements of absorbance were obtained for solution in each tube at 405 nm.

After this, the solution was poured into a volumetric flask just about to the 1dm3 line and then it was left there to cool to the same temperature as the room before filling precisely to the 1dm3 line with distilled water. The molar mass of CuSO4.5H20 was 249.5 so that means 249.5g of copper sulphate was needed to dissolve, in order to make a standard solution, into 1dm3of distilled water. Following this, a linear dilution of the CuSO4.5H2O was made in order to be used to make a calibration curve after using the colorimeter to write down the absorbance of each sample. A linear dilution is diluted with distilled water in order for it to make the concentration weaker and weaker. For this investigation, the dilutions made ranged from 0.01 to 0.1 M/l . It was essential to only make up 10cm3

10 microliters of the sample is then added and the assay absorption is measured at 340nm. If absorbance was above 1.5, samples were diluted.

The same solution of 0.5 ml BSA was then added from test tube 1 to the test tube 2 after being properly mixed, and from test tube 2 the solution was being added to test tube 3, and so forth all the way up to test tube 5, with the same exact procedure. From the last tube, we then disposed the 0.5 ml solution. After above procedures, we now labeled another test tube “blank”; 0.5 ml blank distilled water was purred into the tube with the serial dilution of 1:10. We also had a tube C labeled “unknown” with the same 0.5 ml of solution. And after adding 5ml of Coomassie Blue to each tube (1-5) and to the blank, the result of absorbance was read at 595 nm.

Time) because it had a correlation closest to 1. All three orders were graphed and a linear regression was used to see which graphed order was closest to 1. The order was determined by comparing the concentration and time to the mathematical predictions made using the integrated rate laws. Analyzing each graph and finding each correlation helped determine which graph was closest to 1. The more concentrated a solution is, the higher the absorbance of that solution. This is due to Beer’s Law. The law measures the absorbance of a solution by determining how much light passes through a solution. As the concentration of a solution increases, fewer wavelengths of light are able to pass through the concentrated solution. The absorbance at 60 seconds was 0.573 (Figure 1: Table1). To calculate the concentration (molarity), the Beer’s Law equation was used, Abs = slope(m)+b. Plugging in what is known into the Beer’s Law equation resulted in 0.573 = 3.172e+004 + 0, where the concentration is determined by M = 0.573-0/ 3.172e+004. So, the concentration at 60 seconds using the equation (M = 0.573-0 / 3.172e+004) was 1.824e-5 M. The 1st order graph resulted in k=0.006152 (Figure 1: Graph 1). Other groups also resulted in their decolorization of CV to be the 1st rate

The concentration or molarity of a solution can be seen through the ratio of solute amount to solution volume. This means that when you take the solute amount of a solution in moles and divide it by its volumes in liters you are able to find the solution’s overall concentration or molarity. This is proven in my data table below labeled, Molarity Simulation Data, and it helps to show that when you get the moles of a solute and the volume of the solvent you can easily and accurately figure out the molarity of the solution you are investigating. For example, when there were .75 moles of an energy drink power, and only .25 liters of water to mix it in, as shown in #3 of my data table, I was able to identify the molarity as 3 M through the process of division The way I executed this experiment lets me to see the impressionable relationship between the solute amount in moles and the solution volume in liters and how they affect molarity of a solution. The data table allows me to demonstrate this pattern. My argument is, the molarity of an aqueous solution can be found if you take the moles found in a given solute and divide them by the volume of the solvent. The data presented in this paper proves that the given formula shows the dependent, mathematical relationship that all three of these factors

The Beers Law calibration experiment used many concentrations of crystal violet solutions. Each of these solutions were test and analyzed in order to determine the absorbance of each concentration The results were than graphed and produced a slope of 1.00E05 with an intercept of -2.21E-02.

A = Absorbance difference  = Molar extinction coefficient C = Concentration L = Path length

3. The spectrophotometer was set at 420nm. Distilled water was also used as the ‘blank’.

The absorbance is measured using a Plate reader and a Standard curve is generated. Also, the different types of pipetting techniques are assessed in this Assay.

However, the higher the transmittance percentage, the lower the absorbance for that solution will be. The highest and lowest absorbance for each solution seems to be at 610nm wavelength. It should also be noted that the pH levels in the four solutions are a big factor when finding the absorbance and transmittance. The lower the pH, the lower the absorbance, but the higher the pH, the higher the absorbance. It can be guessed that acid molecules do not take in light absorbance as well as base molecules do.

The higher concentration of a solution, the more light is absorbed. The slope of the calibration curve is y=543949x-1.4302, y being the percent absorbance and x being the phosphate content, this is shown in Figure

Table 1. Water absorbance results Material Amount of water

concentration, record the absorbance readings at a fixed wavelength, and plot the absorbance vs. concentration data. The wavelength of 520 nm was selected for experiment Part