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# Experimental Design and Methods in Chemistry

### Graphing solubility - A student decided to measure the amount of salt that would dissolve in 50 ml of water at different temperatures ...

A student decided to measure the amount of salt that would dissolve in 50 ml of water at different temperatures. The student found that the solubility at 10 degrees centigrade (10° C), was .56 grams of salt. At 40° C, 2.35 grams dissolved and the solubility at 70° C was 3.85 grams of salt. Create a "Best fit" graph for th

### Candle Lab

Experiment Observations Results and Explanations A. Reigniting a Candle B. Water Suck Up C. Extinguishing a Candle with Aluminum Foil D. Candle Condensation E. Extinguishing a Candle with Carbon Dioxide 1. Why would the candle reignite with a match held away from the wick? 2. a) Explain how the candle would

### NMR Spectroscopy - Solve the structure of unknown A

Hi, I have some data to help me solve a structure via High Resolution NMR, however being new to this, I am having extreme difficulty, and was wondering if someone could help please - or even point me in the right direction as how to go about solving for structure A? A has a molecular formula: C12H15O4N. The 13CNMR data sh

### Analytical Chemistry: Making a Stock Solution

A chemistry student is about to make a stock solution of 0.1 molar HCl. He proceeds by adding two 10mL additions of 10M HCL to a 500mL beaker and fill it with water from the sink. Other than not using di-ionized water, what are all other problems associated with this procedure. **No other information given**

### Infrared spectroscopy

On this site http://www.chemguide.co.uk/analysis/ir/interpret.html#top it shows an infra red spectrum of ethanoic acid and shows a very broad trough between 2500 - 3300 cm ^-1 taking this from the point where the line graph starts to drop it looks more like 2800 - 3800 cm ^-1 do you have to take these measurements from

### CHM - Carbohydrates

Please answer the following based on the attached table. Which carbohydrates are reducing monosaccharides? Which carbohydrates are reducing disaccharides? Which are nonreducing disaccharides?

### Statistical Method (Concentration and Absorbance)

1. A gun shot residue containing barium and lead is analysed using atomic absorption. Residue from sample collected in Glasgow and Inverurie are also available Glasgow gun shot residue (n-20) Ba (o.12+/-0,005%), Pb (5.2+/-2.0%) Inverurir (n=5) Ba (0.22+/-0,001%), Pb (7.2+/- 1.0%) (a) Describe the necessary parts of an

### Modern Analytical Techniques

Write an account on what you consider to be the most significant advances made in the field of modern analytical techniques during the last five years. Include specific examples in your answer.

### Types of Stationary Phases used for Chiral Separations in HPLC

Describe the types of stationary phases used for chiral separations in HPLC including structural requirements.

### Beer's Law for Concentration

1. Calculate the concentration of each calibration standard. 2.Plot the data on the attached graph paper. 3. Calculate the slope. What is the average slope? What are the units? 4.Determine concentration of the diluted unknown. 5. determine the undiluted concentration of the unknown. The stock solution is 0.027 M KMnO4

### Energy of a Single Photon

Proteins and DNA absorb light in the 282 nm range in the spectrophotometer. what is the frequency? Obtain the energy of a single photon of this wavelength?

### Von Weimarn Ratio/Gravimetric Factors

3. What information, concerning optimum conditions of precipitation does the von Weimarn ratio give us? Von Weimarn Ratio/Gravimetric Factors. See attached file for full problem description.

### Percent of Manganese in the Sample

A 0.500-g sample is analyzed spectrophotometrically for manganese by dissolving it in acid and transferring to a 250-mL flask and diluting to volume. Three aliquosts are analyzed by transferring 50-mL portions with a pipet to 500-mL Erirnmeyer flasks and reacting with an oxidizing agent, potasium peroxydisulfate, to convert the

### Analytical Chemistry Problem Set

35. You are required to prepare working standard solutions of 1.00 x 10^-5, 2.00 x 10^-5, 5.00 X 10^-5, and 1.00 x 10^-4 M glucose from a 0.100 M stock solution. You have available 100 mL volumetric flasks and pipets of 1.00-, 2.00-, 5.00-, and 10.00-mL volume. Outline a procedure for preparing the working standards. 38. A 0

### Analytical Chemistry Problems

See attached file for full problem description. Please answer the attached questions. Please show detailed work and rationale for the steps to answer the questions. 3. The following is a list of common errors encountered in research laboratories. Categorize each as a determinate or an indeterminate error, and further cate

### Analytical CHM Questions

5. What is a blank? 9. What is a calibration curve?

### Detecting Ultraviolet, Visible and Infrared Light

Would you use the same detector in detecting ultraviolet, visible and infrared light? Why or why not? Explain.

### Volhard vs the Fajan's Methods of Titration

What is the difference between the Volhard and the Fajan's methods of titration? Which is used for acid solutions? Why?

### Internal Standard for Calibration

What is an internal standard and why is it used during calibration?

### Random or Systematic Error with a Pipet

Suppose that a 25-mL transfer pipet consistently delivers 25.031+/- 0.009mL when drained from the mark. Is this an example of random or systematic error?

### How to Prepare a 5 Molar Solution of Sulphuric Acid

How do you prepare a 5 molar solution of sulphuric acid?

### Lowest-Energy Spectroscopic Terms

Show what electronic arrangements (electrons occupying sub shells of different ml and ms) that would lead to spectroscopic terms 6H, 5I and 8S, and identify one element each that have these terms as (see attached) the lowest energy spectroscopic terms. See attached for full formatting.

### 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

### Theoretical Methods: quantum mechanics

Please see attached the file for full problem description.

### 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 &#949; = 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

### Calculate the number of grams of citric acid, C6H8O7, needed to make 2500mL of 0.4 M C6H8O7

1. Calculate the number of grams of citric acid, C6H8O7, needed to make 2500mL of 0.4 M C6H8O7. 2. How many grams of sodium hydroxide, NaOH, would you have to dissolve in 250 mL of water to make a 0.5 M solution of NaOH? 3. How many liters of water are required to make a 0.2M solution sulfide, Na2S, using 200g of Na2S?

### 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?

### Spectroscopic method to distinguish between isomeric acids

What spectroscopic method would you use to unambiguously distinguish between the following isomeric acids? Give an explanation of how the spectra are interpreted to give you an assignment for each compound. (a) CH3(CH2)3CO2H (b) (CH3)2CHCH2CO2H (c) (CH3)3CCO2H