Organic Chemistry Answers

If 1,000.0 g of water from Luboc River contains 0.0075g of Ca²⁺ ions, how many parts per million (ppm) of calcium ions

Which is more stable in each pair given below give reason for your answer

Taking suitable example write the mechanism of benzoin condensation.

1.    The aroma of fruits comes from characteristic chemicals. For example, the aroma of an apple is mainly caused by molecules of C₃H₇COOCH₃ (methyl butanoate) and the aroma of pears by molecules of CH₃COOC₅H₁₁ (pentyl ethanoate). In a futuristic clothing project, two students suggest using methyl butanoate and pentyl ethanoate to form new aromatic fabrics. State the class of chemical compound these molecules belongs to

A solution

of H2SO4 with a molal concentration of 8.010 m has a density of 1.354 g/mL. What is the

molar concentration of this solution?

Assay of Tartaric Acid USP 99.7-100.5%

1. Accurate weigh 2 grams of previously dried tartaric acid.

2. Transfer to a conical flask then add 40 milliliters of water. Mix to dissolve.

3. Add phenolphthalein TS.

4. Equally divide into three Erlenmeyer flasks.

5. Fill in the buret with previously standardized sodium hydroxide (1.013N), then conduct the titration.

6. Record the data for the three trials, then compute for the individual and average percentage purity.

Questions:

1. The burette was filled up to the 0 ml mark, what is the volume consumed for Trial 1?
2. The burette was filled up to the 0 ml mark, what is the volume consumed for Trial 2?
3. The burette was filled up to the 0 ml mark, what is the volume consumed for Trial 3?
4. The accurately weighed analyte dissolved in the matrix, then was equally divided into three Erlenmeyer flasks. What is the weight of the analyte in each flask?
5. What is the molecular weight of the analyte?
6. What is the meq of the analyte?
7. What is the titer value?
8. What is the principle involved in the essay?
9. What is the percentage purity for Trial 1?
10. What is the percentage purity for Trial 2?
11. What is the percentage purity for Trial 3?
12. Using the previously computed individual percentages, what is the average percentage purity?
13. Did the sample conform to the official monograph?

If a 1.25 g sample of magnesium oxide (98.9%) were titrated with 70 ml of 1.04 N of sulfuric acid, what volume of 1.15 N sodium hydroxide would be required in the back titration?

Indicate the specific type of titration used

Given and unknown

Solution

Calculate the total, temporary and permanent hardness of water sample having following analysis: Mg(HCO3)2 = 73mg/l, Ca(HCO3)2 = 162mg/l, CaSO4 = 136mg/l, MgCl2 = 95 mg/l, CaCl2 = 111 mg/l and NaCl = 100 mg/l.

0.2 g of CaCO3 was dissolved in 500 mL of water. 100 ml of this solution on titration required 20 ml of EDTA. 100 ml of an unknown hard water sample with total hardness 600 mg/L was titrated against same EDTA solution. What is the expected end – point?

For the final section, use relevant information from the other sections of your handbook, to give a plan of a multi-step synthesis of

• ethyl ethanoate (CH3CO2CH2CH3), starting from ethanol and ethanal

• N-ethylacetamide (CH3CONHCH2CH3), starting from chloroethane and ethanoyl chloride

You will need to include reagents, reaction conditions and intermediate products involved in each step.

Your handbook will be much more interesting to your audience if pictures of 3D models of your molecules are included where it is appropriate.