A 0. 6875 g rock sample containing an unknown amount of Ca was dissolved in HCl and diluted to 200.00 mL. Aliquots of 20 mL of this unknown solution were added to different volumes of a 8.02?g/mL Ca standard  solution and diluted to 100.00 mL. A plot of absorbance vs. concentration of standard gives a trendline of with slope  of 1746. 7. The solution of 20 mL of unknown diluted to 100 mL and without any standard gave an absorbance of 215.8. Find the weight percent of Ca in the rock.

A solution in part C initially contains (4.06x10^-4) molar SCN¯ and (2.960x10^-3) molar Fe3+. This solution was then measured using the colorimeter, and an absorbance of (4.9800x10^-1) was recorded.The constant determined in part A of the experiment was found to be (3.8200x10^3). Using the data provided above, determine the equilibrium concentration of SCN", [SCN]E in this solution. Note: Your answer is assumed to be reduced to the highest power possible. Your Answer: x10 Answer units

Which rapid and quantitative analysis requires a sample solution of metal ion to be titrated against a standard solution of EDTA, in the presence of a buffer?*   Alkalimetric Replacement Back Titration Direct   Which agent is added into a solution if direct titration is deemed to proceed slowly?*   Indicator Titrant Catalyst Demasking agent   Which method uses an excess solution of EDTA added to a sample and then pH is adjusted for back titration with a metal ion solution?*   Replacement Residual Alkalimetric Direct   Which reagent will form a more stable complex with interfering ions rather than the with the indicator and EDTA?*   Masking agents Demasking agents Chelating agents Complex agents   Which of the following contains a set of incorrectly paired words?* Chelatometry - Complexation / Precipitimetry - Argentometric…

A student makes a Beer's Law plot of A vs [Fe(SCN)2+] in the first part of the equilibrium constant lab, and gets the following information from the trendline. y = 50.7x R² = 0.9999 If the student measures a absorbance of 0.167 for a solution in the second part of the lab, what equilibrium concentration of [Fe(SCN)²+ would be reported?

The local anaesthetic lidocaine is required by the British Pharmacopoeia to contain not less than99.0% and not more than 101.0% of C14H22N2O, calculated with reference to the anhydroussubstance.0.2093 g of a lidocaine sample was dissolved in anhydrous acetic acid and titrated with 0.1025 Mperchloric acid. 8.53 mL was required. Another sample of the lidocaine from the same batch wasfound to contain 0.78% water. Does the sample meet the BP requirements?

Please show your complete solutions. Thank you.

Calculate the initial concentrations for the Fe3+ and SCN- for the data provided in the table.

3. Using the graph provided, find the concentration of a solution that had an absorption of 0.269 when measured at 460 nm in a 1.0 cm cuvette. Absorbance vs. Concentration 0.45 0.4- y = 4.07x - 0.0046 R = 0.99353 0.35- %3D 0.3- 0.25 0.2- 0.15 - 0.1- 0.05 0.000 0.020 0.040 0.060 0.080 0.100 0.120 Concentration (mM) Absorbance at 460 nm

Procedure Preparation of Dilute Solution of Vinegar • Using a 10 mL pipette, transfer 10mL of vinegar into 100 mL volumetric flask.  • Dilute to mark of the volumetric flask using distilled water. B. Titration of Diluted Solution of Vinegar  • Transfer 25 mL of diluted solution to 250 mL Erlenmeyer flask.  • Add 0.5 mL phenolphthalein indicator. Set aside.  • Transfer 50mL of 0.110 M NaOH into a 50 mL burette.  • Titrate the diluted solution until the phenolphthalein endpoint (very faint pink).  • Record volume of NaOH used. Answer the question: What is the experimentally determined concentration of acetic acid in your vinegar solution: (Please give your answer to three significant figures.) ______ M Acetic Acid

Using the concentrations found in the experiment for the iron cation and thiocyanate anion determine the Kc for iron (III) thiocyanate using 1.71mL of iron cation solution and 4.00 mL of thiocyanate anion solution. The absorbance for this mixture at 460 nm is 0.339.