Assignment 4-a

1-11.4 2-33.8 3-25.5 4-19.4

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 104 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.

Determine the slope of the linear regression line for a standard curve of concentration versus absorbance using the following data. Concentration (M)       Absorbance 2.00x10-5                          0.0500 5.00x10-5                          0.130 1.00x10-4                          0.200 2.00x10-4                          0.450 5.00x10-4                          1.25 7.50x10-4                          1.40 Group of answer choice 5.00x10-4 1.00x10-5 1990 0.0420 0.456 0.296

River water analysis of mercury (Hg) yields a spectrophotometric sample signal of 0.712 for a 5.00 mL sample. A 5.OuL spike of 1560 ppb Hg standard produced a signal of 1546. What is the concentration of Hg in the original river water sample? What is the concentration of Hg in the original river water sample? A. 1.109 ppb B. 1.330 ppb C. 1.771 ppb D. 1.546 ppb

Concentration of FeSCN2+ Absorbance (Y axis) Percent Transmittance (%T) (X axis) 100 1.00E-04 0.495 32 2.00E-04 0.955 11.1 3.00E-04 1.398 Calibration Curve (Absorbance vs. Concentration of FESCN²*) 1.6 1.4 y = 4713.6x. 1.2 1 0.8 0.6 0.4 0.2 0.00005 0.0001 0.00015 0.0002 0.00025 0.0003 0.00035 Concentration of FeSCN²+ Absorbance

Determine the standard concentration of A through E and then the absorbance. I just need clarification on if I add together the two ml values given.

Intensity (a.u.) 4000 3352 cm¹ 3500 3000 UNKNOWN B 1710 cm¹ 2000 1668 cm¹ 2500 Wavenumber (cm¹¹) 1500 1101 cm 1000 500

O Macmillan Learning Co(II) was used as an internal standard to analyze a sample of Ti(IV) with atomic absorption spectroscopy (AAS). A standard mixture containing 1.30 µg Co/mL and 1.48 µg Ti/mL measured by AAS produced a signal-to-signal ratio of 2.13 Ti : 1.00 Co. A mixture was prepared by combining 5.50 mL of a Ti(IV) solution of unknown concentration with 3.50 mL of a 13.4 µg/mL solution of Co(II). The absorbance of the mixture at the Ti(IV) wavelength was 0.139 and the absorbance at the Co(II) wavelength was 0.208. Determine the concentration, in moles per liter, of Ti(IV) in the original unknown solution. concentration: M Ti(IV)

the spectra is of a drug either cannabinoid, opiate, MDMA etc, please explain the spectra and what drug could it be

= 1 5 Absorbance vs. Concentration y = 0.2755x 0.2- 0.1- 1.400 2.000 1.800 1.600 1.000 0.200 1.200 0.400 0.600 Concentration (M) Using the calibration curve, calculate the molar concentration for a solution with a measured absorbance of 0.374. Round your answer to 3 significant digits Concentration = M X Sub Absorbance 0.7- 0.6- 0.5 0.4- 0.800

Match each of the definitions with the correct term. A signal B standardization C analyte D stock solution E assay F noise G qualitative analysis H baseline 1 Limit of Detection. J quantitative analysis K matrix L secondary standard M uncertainty N Limit of Quantitation O attenuation P calibration standards Q aliquot R blank. S primary standard making a signal smaller in amplitude a sample that contains the same matrix as the analyte sample, but contains no analyte the process by which the concentration of the analyte in a secondary standard is determine a method of analysis that determines the amount of an analyte the instrument response associated with the presence of an analyte a substance that may not be highly purified, but can be standardized with a primary standard and use to calibrate an instrument Submit Answer Tries 0/12 Post Discussion

which one is the most suitable spectrum? (based on image 6) a/b/c/d/e/

What cause the spikes in the spectrophotometer reading? Explain