Pre-lab 5 - Beer's law

A. Copper sulfate pentahydrate is often used to teach students about Beer’s Law by making a standard curve (linear regression). The bright blue color of the solution has a peak absorbance in the red range of the electromagnetic spectrum. The absorbance value is proportional to concentration. How many grams of CuSO4 5H2O to make up 250 mL of a 0.2 M stock of this solution? B. Using M1V1 = M2V2 how many mL would a student need to measure out in graduated cylinder to make up a 50 mL (V2) solution of 0.1M, 0.05 M, 0.025M 0.0125M solutions for a standard curve at the peak wavelenth for this compound?

A. Copper sulfate pentahydrate is often used to teach students about Beer’s Law by making a standard curve (linear regression). The bright blue color of the solution has a peak absorbance in the red range of the electromagnetic spectrum. The absorbance value is proportional to concentration. How many grams of CuSO4 5H2O to make up 250 mL of a 0.2 M stock of this solution? B. Using M1V1 = M2V2 how many mL would a student need to measure out in graduated cylinder to make up a 50 mL (V2) solution of 0.1M, 0.05 M, 0.025M 0.0125M solutions for a standard curve at the peak wavelenth for this compound? I need help with part B of this question.

A direct ELISA experiment was done to determine the amount of protein present in a sample. A standard curve was prepared by plotting log Absorbance versus log concentration of protein in (ng/mL). The equation of the line is Y= 0.895 X -1.25. If an unknown protein shows an absorbance of 1.23. Calculate the concentration of this protein in the sample in (ng/mL).

Chemistry

GMU QUESTION 7 An ethanol solution of 3.5 mg/100 ml of compound Y (150.0 g/mol) in a 1.00 cm quartz cell has an absorbance (A) of 0.972 at Amax-235 nm. What is its molar extinction coefficient? Report your answer to the correct number of significant figures. Do not include units in your answer.OGMU 2020

Table II Cuvette # Concentration Absorbance 0.50 M 1 1.049 2 0.40 M 0.926 3 0.20 M 0.740 0.298 4 0.10 M 5 0.05 M 0.202 Unknown # 9 0.427 Unknown # 10 7 0.646 Blank (DI water) 0 1. If Beer's Law is valid, the value of "E" should be constant. Use A = E*C*L or E= A/(E*L) and the data from Table II to calculate values of E for the five solutions below The value of L is normally 1 cm so E = A/C in this experiment. Table III Solution # Calculated Values of E 1 2 3 4 5

AP Questions // Questions 10 - 11) A student creates four solutions with varying concentration of FeSCN2 and gathers the following data at 298 K using a spectrophotometer calibrated to 460 nm: [FESCN] Absorbance 1.1 x 10-4 M 0.076 1.6 x 10-4 M 0.112 2.2 x 10-4 M 0.167 2.5 x 10-4 M 0.199 On the axis below, create a Beer's Law calibration plot for [FESCN2*]. Draw a best-fit line through your data points.

PLEASE Answer within 20-30 minutes. Thank you!

Conclusion 5: You are tasked with analyzing a suspiciously pink sample of drinking water to establish if it has unsavory levels of MnO4-contamination. It has an absorbance of 0.83 at 544 nm when measured in a cuvette that is 1 cm across. Using the equation of your trend line from Plot 4, determine the concentration of KMnO4 in moles/liter. Convert this concentration to grams of manganese/liter and compare it to the EPA guideline above.       Trandline is Absorbtion = 2000(Concentration KMnO4) (Y=Mx)

So Please don't provide the handwriting solution

Absorbance 1.40 Beer's Law Plot 1.20 1.00 0.80 0.60 0.40 0.20 0.00 0 10 20 30 40 50 Concentration (M x 105) D The slope for the line is 80.23. Use the Beer's Law plot provided to determine the concentration for a solution with absorbance = 0.5786. M

Do not give handwriting solution.

given the following results " create a “standard curve” (a graph) that shows the concentration on the x-axis and the absorbance on the y-axis" and "a solution of copper(II) sulphate with an unknown concentration was found to have an absorbance of 0.09. Use your standard curve to determine its concentration" ample Number Concentration of Copper(II) Sulphate (mM) Measured Absorbance 1 0   0 2 50   0.12 3 100 0.24   4 150   0.35 5 200   0.47 Unknown   40 0.09

The following Absorbance vs concentration of nitrite graph is obtained for a set of data: Absorbance Vs Concentration y = 1.6628x+0.0373 R? = 0.9893 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0.2 0.4 0.6 0.8 1 Concentration of nitrite (mg/L) Determine the concentration of unknown solution for which the absorbance is determined as 0.69 A. More data is required В. 0.69 С. 0.65 D. 0.39 Absorbance

How do I find Concentration? flask Calculate solution Concentration (M) Volume stock of 0.40 M CuSO4 (ml) Volume of flask (ml) Absorbance at 635 nm(a.u.) 1   2.0 10 .185 2   4.0 10 .362 3   6.0 10 .510 4   8.0 10 .674 5   10.0 10 .843

line of best fit. y=0.001x + 0.1987, absorbance is 1.29. Calculate the concentration of your sample. units must be ug/mL

Given this data, if a CV solution has an absorbance of 1.125, what is [CV]? [CV] / M              A  1.0 × 10–6 M      0.250 3.0 × 10–6 M      0.750     Question 12 options:   4.5 × 10–6 M   5.0 × 10–6 M   5.5 × 10–6 M

+ Slide Play HOMEWORK Keynote Live On Table MAY 4 LAB 11 Spinal Cord ✓ LAB 12 Brain Gross Anatomy and Crania Nerves: SPECTROPHOTOMETRY EXP 10 ✓ 1.Which solution will absorb the most light? A 5M solution or a IM solution? 2.We have two blue solutions. The absorbance of Solution A was higher than the absorbance of Solution B. a. Which solution is more concentrated? b. Which solution is darker? 000 Chart T Text Shape Media Comment 18 1 FB