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Experimental Design and Methods in Chemistry

Interpretation of 1H NMR 4-vinylbenzoic Acid

I am doing a lab report and need to interpret the 4-vinylbenzoic acid 1H NMR spectrum above. 4-vinylbenzoic acid looks like this: I was given a help on brainmass: "4-Vinylbenzoic acid is an aromatic carboxyllic acid. there are three distinct groups in this molecule: benzene ring,vinyl group and -COOH group. In all there

1H NMR Spectrum Interpretation

I need to: provide an interpretation for all protons in the 1H NMR spectrum of 4-vinylbenzoic acid and indicate how the 1H NMR spectrum of the corresponding methyl ester would differ from that of the acid. On the 1H spectrum, I see a quartet around 6.8ppm which I don't know where it comes from, because I think it should be a

1H NMR Spectrum for 4-Phenylphenol

Refer to attached document. I have an 1H NMR spectrum of 4-phenylphenol (400 Mhz, CDCl3 solvent) and I have the spectrum assignment for the chemical shifts and corresponding protons. I would like an explanation of WHY each shift correspond with their particular protons. For instance, why are the protons adjacent to the pheno

Potassium Wave Motion

The potassium spectrum has an intense doublet with lines at 766.494 nm and 769.901 nm. Calculate the frequency difference between the 2 lines?

Spectrochemistry: Dilute the stock solution

Please help with the following problem. A spectrophotometric assay was to be carried out on a compound ε = 5000. The stock solution of standard had been made with a concentration of 0.0203M. Given a 1.000cm path length and a desired absorbance around 0.4-0.5, by what factor should the stock solution be diluted? (SHOW

Miniature Laboratory Volcano Empirical Formula

63. A miniature laboratory volcano can be made with ammonium dichromate. When ignited it decomposes in a fiery display. (NH4)2Cr2O7(s) N2(g) +4 H2O(g) + Cr2O3(s). If 5.0g of ammonium dichromate are used and if the gases from this reaction are trapped in a 2.0 L flask at 25oC, what is the total pressure of the gas in the flask?

Analytical Chemistry - Fluorometric method

(See attached file for full problem description) --- 23. In developing a fluorometric method, you measure a standard Analyte at 3.00 ppm (w/w) in the matrix at three different pH values: 2,5,8. You then compare the effects of internal calibration by adding 2.00ppm Analyte to your matrix vs external calibration via pure sta

Analytical Chemistry with Vitamin B

22. A company produces vitamin B tablets tha claim to provide 100mg of riboflavin. A bottle is drawn from the stock, and one pill is determined to contain 100.9 mg(= +/-1.1mg) of riboflavin. A)How many samples are needed to confirm with 95% confidence that the pills contain at least 100 mg of riboflavin. B) How should

NMR: Resonance Frequencies

1. a) Calculate the resonance frequencies of the following nuclei, given the values for the nuclear magnetic moment and spin, at a field strength of 10 kG. B_N = 5.05 * 10^-24 ergG^-1. nucleus I u (in multiples of B_N) 11B 3/2 2.688 17O 5/2 1.893 50V 6

Use of spectrophotometry to determine Ka

This involves the use of the equation; pH = pKa + log (activity coefficent of anion) + log (D -Dha)/(Da- - D), from the equation it is neccesary to plot pH against log(D - Dha)/(Da- -D). This appears to be the straight line eqn which can be solved (y = mx + c) for the function pKa + log (activity coefficient of anion

The Oxidation of Alcohol by Dichromate Ion

1) I'm given a spectrophotometer. How can I determine the rate law? I can only use the spectrophotometer to determine %T. How can I get from %T to concentration? What strategy do I have to use? Can you provide me a step by step strategy about how to get "from %T to concentration" and how to get "from concentration to rate law"?

Restaurant - Boiling Stones

I have a question that I found in a text book, can anyone help me answer it? It seems to be safe. Some of you are concerned with the fact that the operator of a Vietnamese restaurant used some stones as "boiling chips" in the pots where they cook food. Please provide a paragraph with rationale to support your argument/conc

Lab Experiment: How do I dissolve dirt?

Purpose: To introduce the student to a real world application of concepts learned so for in Analytical Chemistry. Apparatus: To be determined. Introduction: In this experiment you will be given a beaker containing dirt. Dissolve .25 grams using any method/chemicals/devices possible. You are NOT allowed to use hydrofluoric

95% Confidence Level and Systematic Error

We are using the book Analytical Chemistry 7th edition by Skoog, West, Holler, and Crouch This question requires all equations to be written out. Thanks so much! To test the quality of work of a commercial laboratory, 15 replicate analyses of a purified benzoic acid (68.8% C, 4.953%H) sample were requested. The absolute

Gas Chromatogram

Please refer to the attachments provided. When I did the gas chromatogram, I made a careless mistake, by not labeling the printout(A-D); A-C the 3 distillation fractions and D the undistilled residue. On the 1st printout w/ 4 peaks, I know that the highest peak is A and on the printout w/ two peaks I think the peak on the rt

Can equilibrium be maintained

When distilling toluene and benzene under equilibrium conditions can equilibrium be maintained if a) pressure is changed and if b) pressure and temp are changed? Explain by phase rule

HPLC Column

An HPLC column of length 15cm and ID of 4.6mm is tightly packed with monodisperse ODS particles of diameter 3:m surface area 300m/g^2 and density 1.2g/mL. Dead volume is 1.2mL. Assuming that the particles are tightly packed and that the void volume is essentially due to the pore volumes of the particles, calculate: 1. the # of

GC Problem

Calculate: 1. Corrected retention times for air and 3 alcohols 2. Specific retention volumes for 3 alcohols 3. Distribution constant for 3 alochols 4. Capacity factor for 3 alcohols 5. The average number of theoretical plates and the average height of a theoretical plate for the column Given: 1. Column length: 1.1m ID

Chemical Separations Problem

The H (height equivalent of a theoretical plate) value for an HPLC column at mobile phase flow rates of 1ml/min, 3ml/min and 4ml/min are 4.1mm, 4.7mm and 5.675mm. Calculate: 1. The van Deemter parameters A, B and C 2. The flow rate at which H is a minimum and the value of H at this flow rate 3. The efficiency N if the length

Preparation of solutions

Hi-1st of all, would you please send back an email address so I may contact someone on the 3rd shift about something that was done on 3rd? Secondly, is there a way to request work to be done by a certain person if they are available? A couple of you last night were just wonderful!!!Olivia Problem: Describe how you would prepar

Chemical separation on a GC instrument

Given: 1. GC instrument 2. polysiloxane column 3. 1mM solution of each of the following compunds in methanol. Compounds divided into 3 separate groups: 1. Carboxylic Acid: a. benzoic acid b. Phthalic acid c. Toluic acid 2. Amino: a. aniline b. 4-aminotoluene c. ortho- pheylenediamine 3. Amino

Method Set-Up for a Chemical Separation

Suggest a buffer and mobile phase composition to get the best separation given: 1. HPLC instrument 2. C18 reverse phase column 3. 1mM solution of each of the following compounds in Methanol 4. Mobile phase is methanol-buffer mixture Compounds are 3 seperate groups: 1. Carboxylic Acids: a. Benzoic acid b

Capacity Factor Problem

Question: Two analytes A and B, have retention times of 13.5 min and 19.5 min, with peak widths of 2 min and 2.8 min for a mobile phase composition of 20% methanol and 80% H2O, on a 15 cm C18 column which has a dead time of 1.5 min. Determine the composition of methanol and H2O at which the capacity factor for A becomes 2. What

Analyte separation problem

The fraction of an analyte in the rth stage of a N stage separation if given by f(N,r)=(N!/r!(N-r)!p^r q^(N-r). Given: distribution ratios of 0.5 and 1.5 Stages 50 and 200 Phase volume ratio 0.3 What is the fraction of analyte in each stage and the stage number for analytes with the given dis

Capillary condensation in nanotubes

Is anyone familiar with a recent report where liquid water has been condensed inside a carbon nanotube and then imaged with an electron microscope at very low pressure (10^-5 torr)? Supposedly the water does not evaporate at this low a pressure. Is this truly possible and why? Does anyone have the reference for this experimen

Solvent-Solvent Extraction

Green Slime, an uncharged organic dye, is present in 600.0mL of water at an unknown concentration. The sample is extracted with 75.00mL of cyclohexane. After the extraction, the absorbance of the cyclohexane phase, measured at 635nm in a 1.00cm cell, is 0.870. The absorbance of a blank (pure cyclohexane) is 0.007. Using Beer's L

Absorption and Fluorescence

Question: An aromatic compound, RX, fluoresces at 470 nm (quantum yield = 0.1) after excitation at 340 nm. The molar absorptivity of RX at 340 nm is 1100. How much energy has been lost by non-radiative means or remains with the compound after it fluoresces at 470 nm? How many joules of energy per mole of 340 nm photons is retain