Trace Evidence.edited

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

Discuss the similarities and differences between the following terms applied in a particular kind of forensic analysis.  Enzyme inhibition assay and enzyme-linked immunosorbent essay

You work in a research organization that is looking for markers of various diseases that can be used as a diagnostic for the disease. It has been reported in the past that high levels of Cu are found in the sweat of people with cystic fibrosis. One of the research projects is focused on looking for high levels of Cu in samples that can be obtained non-invasively such as saliva, sweat, hair, nails, etc. The lab will analyze large samples for Cu. What instrument would you recommend purchasing to support this work, Atomic absorption spectrophotometer or an inductively coupled plasma atomic spectrophotometer? Explain the basis for your decision.

II. b) What is the difference between liquid-liquid, solid-liquid and solid-phase extraction? Complete the table below and sort the following examples in the correct column: Steeping tea, washing an organic phase (workup), brewing beer, chemical desalting of crude oil, activated carbon sugar decolorization. liquid-liquid solid-liquid solid-phase Phase that contains analyte before extraction? Phase that contains analyte after extraction? Example(s)

The light absorbance A of a molecule in solution is measured as a function of concentration [X]. [X]/M                             A                            0                                     0 1.0 × 10–4                      0.157 3.0 × 10–4                      0.482 5.0 × 10–4                      0.713 7.0 × 10–4                      1.15 9.0 × 10–4                      1.37 Use spreadsheet software to graph the data and calculate a best–fit linear trendline. What is the equation of the line that best fits the data?   Question 5 options:   A = (1.55 × 103 M–1) [X] + (4.93 × 10–4)   A = (1.13 × 103 M–1) [X] + (2.52 × 10–4)   A = (9.94 × 102 M–1) [X] + (3.81 × 10–4)

Scientists study the impact of changing only one component of a cancer treatment in a laboratory. Which of the following describes the study? controlled experiment observational study conceptual model computational study

M (2022-23) Unit 1: Mole Concept, Unit 4 (FR) (Version 2) Assessment: Chemical Reactions 0.90 0.80- 0.70- 3 0.60 0.50- 0.40- 0.30- Absorbance 2. To spectrophotometrically determine the mass percent of cobalt in an ore containing cobalt and some inert materials, solutions with known [Co²+] are prepared and the absorbance of each of the solutions is measured at the wavelength of optimum absorbance. The data are used to create a calibration plot, shown below. 0.20 0.10- 0.00+ ㅏ 0.005 0.010 34 0.015 Concentration (M) .04 co₂ 100- pertoc A 0.630 g sample of the ore is completely dissolved in concentrated HNO3(aq). The mixture is diluted with water to a final volume of 50.00 mL. Assume that all the cobalt in the ore sample is converted to Co²+ (aq). (a) What is the [Co²+] in the solution if the absorbance of a sample of the solution is 0.74 ? (b) Calculate the number of moles of Co²+ (aq) in the 50.00 mL solution. (c) Calculate the mass percent of Co in the 0.630 g sample of the ore. Answer…

■ True or False: in a TOF analyzer, a fragment of low mass reaches the detector first ▪ In GCMS when we know what analytes we are measuring we use not know what analytes are in the sample we use than scan. ▪ A) Scan; SIM ■ B)SIM; scan • C) SIM; SIM mode. When we do mode. SIM allows greater sensitivity

The spectroscopic data in the table is generated with five solutions of known concentration. Concentration (M) 0.0133 m= 0.0266 0.0532 0.106 0.213 Absorbance 0.1271 What is the intercept of the linear regression line? 0.08531 0.5388 1.069 Use a spreadsheet program, such as Microsoft Excel, to graph the data points and determine the equation of the best-fit line. 1.954 What is the slope of the linear regression line formed by these points? M-1

Table 1. Data on EDTA Standardization Weight of CaCO3 (g): 0.2003g Trial Volume of EDTA (mL) Molarity of EDTA (M) 1 8.60 2 8.50 8.55 Average Molarity of EDTA (M)

6. The equation of Beer Lambert's Law is A = Ebc. If the 'b' is distance, 'E' is absorptivity, and 'A' is absorbance, what does the 'c' represent? O Intensity Analyte concentration Analyte transmittance O Frequency

use analytical separation and analyses to outline analytical separation method protocols that can be employed to recover extremely high deposit of heavy metals and particulate matter in the river making wholesome for drinking in illegal mining communities .

From the data in Table 2.5, compute the concentration of the undiluted and diluted ovalbumin samples (make sure to account for the appropriate dilution factors, DF, in the computation).

From the following data, calculate the concentration of the analyte in the sample read at 700 nm: Absorbance of unknown sample = 0.807 Absorbance of a 130 mg/dl standard = 0.234 Do not answer in image format. Maintain accuracy and quality in your answer. Answer completely.

HDPE and PS are both inert to bases and acids, which plastic would you rather chose to put 1 Liter of 6M HCl for general chemistry lab? Explain why.

Real life applications of standardization of NaOH.

This question has multiple parts. Work all the parts to get the most points. A solution of a dye was analyzed by spectrophotometry, and the following calibration data were collected. Dye Concentration Absorbance (A) at 475 nm 0.50 x 10 M 0.24 9. 1.5 x 10 M 0.36 2.5 x 10 M 3.5 x 10 M 4.5 x 10 M 0.44 0.59 0.70 a Construct a calibration plot, and determine the slope and intercept. Slope = y-intercept =