Explore BrainMass

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

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"?

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

GC Problem

Calculate: 1. Corrected retention times for air and 3 alcohols 2. Specific retention volumes for 3 alcohols 3. Distribution constant for 3 alcohols 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 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

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

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

Determine Molar Absorptivity

A red-colored complex PbX4 prepared from Pb with ligand X() shows promise as a means to determine trace levels of lead in the environment. The analyst prepares five standard solutions (A, B, C, D, and E) of PB: 30, 60, 90, 120, and 150 ppm, respectively. 5 ml of each solution is mixed with 5 ml of 0.10 M X. The transmittance of

Laboratory Questions

A laboratory has four hoods each of which is 39 inches wide. When the hood door is open to a height of 8 inches and the hoods are operating, the average air velocity through the hood is 170ft/min. a. Evaluate the total ventilation rate for this room assuming that there are no other exhausts. b. The laboratory is designed for

Calculating Absorptivity

I have tried to play with all the numbers in this question, but nothing seems to be working. Nitrite ion, NO-2 is used as a preservative for bacon and other foods. It has been the center of controversy since it is potentially carcinogenic. Here is an abbreviated procedure for the determination: Step 1: 50.0 mL of unk

Identifying different solutions.

If I had 5 solutions that are not labeled (the solutions are ethanoic acid, calcium hydroxide, potassium bromide, sodium chloride and nitric acid) is there a way of identifying which one is which without using an indicator?