Prietha.Thavakumaran.Experiment2

Do not give handwriting solution.

please help with the question

PLEASE Answer within 20-30 minutes. Thank you!

3

B 50ng/ml C500 ng/ml

help

A water sample was analyzed for iron content using the iron-phenanthroline method. Using the set of data from Question 15 (as presented below), Reagent Blank Absorbance Absorbance (au) Reagent Blank Absorbance 0.003 Concentration of Stock Solution: 10 ppm Volume of Stock Solution (mL) Total Volume of Standard Solution (mL) 0.50 10.00 1.00 10.00 2.00 10.00 3.00 10.00 4.00 10.00 5.00 10.00 Volume of Trial Unknown Solution (mL) 1 5.00 2 5.00 3 5.00 find the true concentration of Fe2+ of the original sample. A) 5.12 ppm B) 2.56 ppm 2.52 ppm D) 5.05 ppm Concentration of Standard Solution (ppm) Total Volume of Unknown Solution (mL) 10.00 10.00 10.00 Absorbance (au) 0.012 0.132 0.267 0.349 0.428 0.560 Absorbance (au) 0.289 0.296 0.281

Answer both questions please it wouldn't hurt 1) For the following write out the Ksp expression: Note: If the ion doesn't have a superscript add in "1" and start with the cation then the anion.   Example of format: CuCl2 (s)   Ksp = [Cu^2+]^1[Cl^1-]^2   (a) CaF2 (s)   Ksp = []^[]^   (b) Al2S3 (s)   Ksp = []^[]^[]^ 2)  Calculate the silver ion, of a solution prepared by dissolving 1.00 g of silver nitrate and 10.0 g of KCN in sufficient water to make 1.00L. Kf = 1.00 x 1021   Ag+(aq) + 2 CN- (aq) ↔ [Ag(CN)2]- (s)

calculate the [FESCN2+] using volumes of stock solutions. Presume that all of the SCN- ions react. Next, record the light absorbance values of each standard solution. Volume Volume Volume [FESCN2+] Absorbance Standard Fe(NO3)3 SCN- H2O sample (mL) (mL) (mL) 1 2.50 2.00 20.50 0.1811 2 2.50 1.50 21.00 0.3219 2.50 1.00 21.50 0.4981 4 2.50 0.50 22.00 0.6328 Stock [Fe(NO3)3] = 0.200 M, Stock [SCN-] = 0.0020 M. %3D

The spectroscopic data in the table is generated with five solutions of known concentration. Concentration (M) 0.0179 0.0358 0.0716 0.143 0.286 Absorbance 0.1425 0.1896 0.5722 1.126 2.110

50 Experiment 6 Qualitative Analysis 2. Write the chemical formula for each of the following compounds: a) Iron (III) hydroxide b) Zinc sulfide c) Tin (II) perchlorate d) Cobalt (II) iodide e) Potassium nitrite f) Aluminum bromide g) Cobalt (III) carbonate h) Lead (IV) nitrate i) Ammonium oxalate

1. A student performed this experiment and obtained the following concentration values: 0.02813 M, 0.02802, and 0.02788 M a. what is the mean concentration? b. what is the standard deviation of these results? 3. how would the following errors affect the concentration of Cl- obtained in question 2b? give your reasoning in each case. a. the student read the molarity of AgNo3 as 0.02104M instead of 0.02014M b. the student was past the endpoint of titration when he took the final buret reading.

6. Given that the concentration of ascorbic acid is ~0.001 M in lemon juice, is this error significant? Why or why not?

Describe and explain the sorption of uranium as shown in figure 7-12. SR stands for Suwanee River, and all abbreviations are explained in the figure caption.

The first photo is the data, second photo is the question! thank you!

Find (M) for [FeSCN^2+] using the following info: 0.200 M (Iron (III) nitrate) Fe(NO3)3 (mL) = 17.98 mL 0.00200 M (Potassium thiocyanate) KSCN (mL) = 1.97 mL 0.815 Absorbance

Using the two images attached please write one paragraph EXPLAINING THE ANALYSIS Please please please answer as fast as possible Please please try to answer

4. You prepare several dilutions of an unknown compound. You measure the absorbance of each solution at 340 nm using a 1 cm cuvette (your results are listed in the table below). What is the extinction coefficient (in (M•cm)') of the compound? (Hint: assume that each of the individual values contains some degree of experimental error.) Concentration(uM) Absorbance at 340 nm 10.0 0.011 20.0 0.023 40.0 0.066 80.0 0.119 160.0 0.189

Calculate the molar concentration of Fe3+ and SCN- in each of the three unknown samples (sample 4,7,and 10) made from Table 2 immediately after each sample was prepared, before the reaction occurs at all.

I need help with question 5? I am confused on question 5a and what it means?

the question states that the Ka value was 3.0 x 10-8 but in step two to calculate the value of pKa you calculated using the -log of 30.0 x 10-8 why did you use that number instead?

Pretend you repeat the experiment using a different unknown chromium salt. The measured absorbance of solution "beta" is 0.65 AU. If the dilution factor between solution "alpha" and solution "beta" is 20x (twenty-fold), what's the concentration of chromium(VI) in solution "alpha"? Use this Beer's plot in your analysis: Absorbance (AU) 1.0 0.8 0.6 0.4 0.2 0.0 Absorbance vs. Concentration of Chromium (M) 0.00000 0.00005 0.00010 Concentration (M) 0.00015 0.00020