Module #2 Post-Lab Question Submission

pls help fill in the missing parts

4- A sample containing H2C204 had a purity equal to 90.50% (w/w). An unknown mass of this sample was dissolved in water and transferred to a 50.00 mL flask. An aliquot of 25.00 mL was transferred to an erlenmeyer flask and 50.00 mL of a 0.2000 mol L^-1 NaOH solution were added. %3 Excess NaOH was titrated with 0.09000 mol L^-1 HCI solution using 2.000 mL. Calculate the mass (g) of the sample used. Data: H = 1.008 C= 12.01 O = 16.00

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A liquid sample was analyzed for Fe³+. A plot of absorbance (y-axis) vs. concentration (ppm; x-axis) of the external standards produced a calibration line with an equation y = 0.2256x -0.0903 (R² = 0.9973). The absorbance of the sample was 1.25. Determine the amount of Fe³+ in the sample (in ppm).

Page of 5 O + 3 ZOOM Question 1: Using a well-known protein estimation technique, absorbance reading for a set of standards were obtained. You were required to plot the data. Which graph would you use? Plot the data using the graph type. Protein Absorbance concentration (mg/mL) (a.u.) 0.01 0.05 0.12 5 10 25 0.25 0.63 1.25 50 Question 2: Enzymes are biological catalysts and perform important biochemical reactions in the body. A group of scientists discovered a new enzyme – Enzyme X. To understand the working of this enzyme, they performed biochemical assays to assess the activity of the enzyme. The results for which are shown in the table below. Based on the information provided in the table, please state which graph would you use? Plot the data using the graph type. Enzyme activity (%) 35 55 pH 3 4 5 68 6 79 7 98 85 20 8 9 10

The absorbance of an unknown dye solution is measured to be 1.06 by a spectrometer. The calibration plot of the spectrometer is provided below. What is the molar concentration of the unknown sample (in mole L)? Absorbance vs. Molarity 18 y3 67024x-0.0343 16 14 12 1 0.8 0.6 0.4 0.2 01 0.2 0.000005 00001 0000015 Concentration of solutions, mol/L 0.00002 0.000025 000003 0 163e-5 O 2.35e-6 0 163 0 235 Absorbance

Consider the reaction : A+B 2 AB. A calibration plot was constructed using x as the concentration for AB in M and y as the absorbance value of AB, it provided the linear equation : y=25x+0.0008. Determine the concentration of AB in M if the absorbance value is 1.22. Round and report your value to the THIRD decimal place. Numeric value only, no unit. No new data to sa IMG 0915.jpeg e to search PrtScn Home

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50 Percentage Red No. 40 Soln 100% 80% 60% 40% Table 4.1: Dilutions of Red No. 40 & Absorbance Volume of Red No. 40 Soln (mL) 10me 8mL опи 4mL Percentage Red No. 40 Soln 100% 80% 60% 40% 20% Volume of DI Water (mL) OML 2mL LIML M UML 8ML Table 4.2: Dilutions of Red No. 40 & Absorbance Concentration Red No. 40 2. Report the wavelength with the maximum absorbance of Red No. 40 dye. Absorbance 20% 2ML Part A: Making a Calibration Curve for Beer's Law 1. Calculate the concentrations of each of your diluted Red No. 40 solutions and add these to Table 4.2. Show at least one sample calculation in the space below. 0.251 0.192 Total Volume 0.181 0·119 0.060 (mL) 10 mL 10 mL 10 mL 10 mL 10 mL

The concentration of nitrite (NO2) in the unknown sample was determined by a direct (ordinary) calibration plot as shown below: 0.300 Absorbance at 520nm 0.250 0.200 0.150 0.100 0.050 0 0.564 µg/ml 0.200 μg/ml 0.754 µg/ml 0.902 µg/ml y = 0.1793x + 0.0763 R² = 0.9969 0.1 0.2 0.801 μg/ml If the absorbance of the unknown sample was measured 0.238 at 520 nm, what would be the concentration of nitrite? 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Nirite (µg/ml)

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To determine the molar concentration of a metal ion in a solution of unknown concentration, a student fırst made five standard solutions that contain the metal ion of interest and measured the absorbance of each solution in a spectrophotometer at its Amax- A calibration curve was obtained that had an equation of y = 5.747 x + 0.013 Next, the student pipetted 15.0 mL of the initial solution of unknown concentration into a 100.0 mL volumetric flask, and filled the flask with deionized water to the line. The absorbance of this final diluted solution was found to be A = 0.226 at Amax. The color of the original and diluted solution was blue. What is the molarity of the original solution, as well as an approximate Amax for this metal ion? 2max = 599 nm and concentration is 0.247 M Amax 457 nm and concentration is 0.247 M %3D 2 max = 457 nm and concentration is 0.0371 M 1 max 599 nm and concentration is 0.0371 M Amax = 599 nm and concentration is 0.00557 M

-3 A 0.3202 (±0.0001) g sample of a pure monoprotic acid required 20.04 (±0.02) cm° of 0.1005 (±0.0005) mol dm neutralisation. Find the molar mass of the acid in g mol together with its uncertainty also in g mol, with an appropriate number of digits. NaOH for -1 Select one: a. 1.59 x 102+ 0.2 g mol b. 1.60 x 10 + 0.03 g mol C. 1.590 x 102 + 0.03 g mol d. 1.590 x 10- + 0.2 g mol 1.60 x 10-+0.2 g mol е. Clear my choice

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…

urses/ 2951 2. A linear standard curve of KMnO4 is prepared from a set of standard solutions by plotting absorbance (y) vs. concentration (x). Use Logger Pro (as described in the Data Analysis for this experiment), or Google Sheets/Excel, to plot this standard curve using the data in Table 1. Help with spreadsheets [PDF] Table 1: Data for the standard curve of KMnO4 Absorbance Concentration (M) 0.372 6.00 x 10-4 0.298 0.223 0.149 0.0744 After plotting the standard curve, enter its slope below (not the equation of the line). Report your answer to 3 significant figures. If your answer ends in one or more zeros, use scientific notation. Slope = 4.80 x 10-4 3.60 x 10-4 2.40 x 10-4 1.20 x 10-4 M-1 M 3. Suppose that an unknown sample is analyzed spectrophotometrically at the same wavelength that was used for the standard curve and the absorbance was found to be 0.186. Use the standard curve to find the concentration of the unknown. Hint:

How do I find the [FeSCN]^2+ value?

Gb6cd_i-5c7IV_IVquz8U4UO2epq7z4kBnpYZ5iA/edit > 2 ons Help Calibri - - [12] + B 7 U . UA 2 3 ge 2: Problems of Water and Air Quality Questions 1. Why is it recommended to have a carbon monoxide detector on each floor of a home? Et © ª @ E- E 4-B-E- 2. What impact would the increased use of electric vehicles have on environmental damage caused by acid rain? 3. Why is ground level ozone most likely to reach its highest concentrations on hot, sunny days during periods of heavy traffic in large cities? Page 3: More Air Pollution Issues: Questions 4. The COVID-19 pandemic forced many people to work from home for extended periods. During these periods, many cities reported unusually low levels of smog. Suggest an explanation for this observation. Page 4: Water Pollution: Questions 5. Explain how ozone can be both harmful and beneficial. 6. India relies heavily on burning coal to generate electricity. How does India's reliance on coal contribute to the poor air quality experienced in many of…

Table 1.0 of data showing calibration standards prepared by dilution and the absorbance Concentration CuSO4 (M) Volume of 0.5M (ml) Volume of D/Water (ml) Absorbance 0.00 0.10 0.20 0.30 0.40 0.50 II. 0.00 1.00 2.00 3.00 4.00 5.00 5.00 4.00 3.00 2.00 1.00 0.00 1. Construct a graph of concentration against absorbance, clearly show a best fit line. Find regression of your graph. Show how 0.000 0.406 0.638 0.854 1.202 1.276

After determining the absorbance of several standards of known concentration, the trendline for a calibration curve (AKA a standard curve) plotting absorbance (y-axis) against concentration (M, x-axis) is determined to be y = 4.943x + -0.0001 The absorbance of a solution of unknown concentration is determined to be 0.48. Calculate the concentration of the unknown solution in M. Give your answer to three decimal places.

Please explain on how to this problem. Thank you!

In spectrophotometric analysis, the relationship between the absorbance A and the analyte's concentration C is: A = ebC + Ablank What is the molar extinction coefficient I and its absolute uncertainty if A is 0.68 ± 0.06; Ablank is 0.06 ± 0.01; b is 1.00 cm; and C is (0.45 ± 0.03)x10-5 mol/L?

A student prepared four standard solutions of (NH4)2Fe(SO4)2 and measured their absorbance at 505 nm.  She created a calibration plot with the best-fit line of y = 9372 x + 0.0539.  She measured the absorbance of her diluted unknown sample solution as (4.69x10^-1) nm.  If she prepared her diluted sample solution by diluting 10.00 mL of the original solution to a total volume of 50.00 mL with deionized water, what is the concentration of Fe2+ in her original solution?  Answer in units of M. Note: Your answer is assumed to be reduced to the highest power possible.

The answer is 0.372 ug/mL

What is the key equation for spectrometry experiments? O q rxn = -q_cal %3D O d=m/V O A= ebC O at endpoint, mol acid = mol base

A 10.00 mL of natural water sample containing Ni2+ was pipetted into a volumetric flask and diluted to 50.00 mL with pure water. In the second 10.00 mL of natural water sample transferred into a volumetric flask, exactly 4.00 mL of a Ni2+ solution with a concentration of 5.99 mg/L was added and then diluted to 50.00 mL with pure water. The measured absorbance is A1= 0.436 and A2 = 0.663. What is the Ni2+ concentration in unit of mg/L in the natural water sample?

What are the errors in the following answer? (4-6 total errors in answer)

part A:> to Calculate Concentzahion, use M,V, = M2V2 AB1 - 0.025 M X 2.5 ml = ax 5 ml %3D 0.0125 M 0.01 M x 2. S ml= 5°-]x Ŝ ml [s2] = 0.008 M 0. 002 M 11 2 a - X = 0. 01 M Sohtion a 9- X timels) 9-X ABI 0-0125 0-0025 0.01 0. 223 84.8 0.016구 0.0016구 0.015 0.10 구 니1.2 AB 2 0.0 S16 19.5 O.02 0. 00 1 0. 이19 AB 3 0. 0164 0.0816 28.5 0.이구8 0. 0014 AB 니 0. 0022 0.011 구 0.172 60 AB § 0.이139 0.270 95.2 O. ol14 0.0027 0.008구 A8 6 0. 389 14 5.5 0.0096 0.0031 0.0065 AB구

1. Data & Results 4.0 mglmL Concentration of stock solution (include units): Table 1-Beer's Law Plot Data V Volume of standard solution dispensed (mL) M, Diluted concentration (include units) Sample Absorbance A 2.00 mL 0.084 4.00 mL 0.173 l6.00 mL 0.259 8.00 mL 0.340 E 10.00 mL 0.418 Equation of trendline from Beer's Law plot: whats the diluted concentration and equation of trendline from the beers law plot once created?

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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.