Interpretation:
The reason for the low recovery of the crystal in the experiment performed by crystallization of biphenyl needs to be explained, if the sample weigh 0.5 g with 5% impurity and after crystallization the crystal dried and weigh 0.02 g.
Concept Introduction:
Organic compounds are mainly covalent compounds in which C-C, C-H and C-X bonds are present. Here, 'X' indicates heteroatom which is present in
A polar covalent molecule will be soluble in water whereas a non-polar covalent compound will be insoluble in water based on the concept of "Like dissolves like". Some of the polar compounds are also not soluble in water as they cannot form hydrogen bonding with water molecules.
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EBK A SMALL SCALE APPROACH TO ORGANIC L
- Suppose that you have a 1:1 mixture of compounds that is comprised of compound X and compound Y. You desire pure compound X and are planning a recrystallization to enhance the purity. Which solvent below is optimal for your recrystallization? Ethanol (boiling point = 78 °C) Solubility At 0 °C 100 °C Compound X 0.05 g/mL 0.20 g/mL Compound Y 0.02 g/mL 0.40 g/mL Water (boiling point = 100 °C) Solubility At 0 °C 100 °C Compound X 0.02 g/mL 0.05 g/mL Compound Y 0.01 g/mL 0.10 g/mL Methanol (boiling point = 65 °C) Solubility At 0 °C 65 °C Compound X 0.04 g/mL 0.10 g/mL Compound Y 0.02 g/mL 0.30 g/mL Acetone (boiling point = 56 °C) Solubility At 0 °C 56 °C Compound X 0.10 g/mL 0.50 g/mL Compound Y 0.20 g/mL 0.50 g/mL Ethyl Acetate (boiling point = 77 °C) Solubility At 0 °C 77 °C Compound X 0.10 g/mL 0.60 g/mL Compound Y 0.30 g/mL 0.60…arrow_forwardbeer. A 2.39- mg sample of safrole was dissolved in 103.0 mg of diphenyl ether. The solution had a melting point of 25.70°C. Calculate the molecular weight of safrole. The freezing point of pure diphenyl ether is 26.84°C, and the freezing- point- depression constant, Kf, is 8.00°C/m.arrow_forwardb) Will the sample be contaminated with any of the impurities? Calculate the percent purity of the initial sample (in terms of compound A) - ( i.e. express the amount of compound A in the initial sample as a percentage of the mass of initial sample). Calculate the percent purity of the final sample (in terms of compound A) - (i.e. express the amount of compound A in the final sample as a percentage of the mass of final sample). Did the recrystallization procedure result in an increase of the percent purity of compound A in the sample? Comment on the results.arrow_forward
- A 1 mL sample of glycogen was calculated to contain 35 µmol (micromole) glucose. To 1 mL of this sample was added 2 mL of 2 M HCL. It was then hydrolysed by boiling the solution for 15 minutes. After boiling the hydrolysate was cooled and made up with H2O to a final volume of exactly 10 mL. The glucose was measured in this solution and found to have a concentration of 570 µg/mL (microgram/milliliter). i) Calculate the mass (mg) of glucose in the 10 mL of hydrolysate. As the 1mL of glycogen sample was made up to a final volume of 10 mL, this mass of glucose was produced by the hydrolysis of the original 1 mL glycogen sample. ii) Calculate the amount (µmol) of glucose produced by the hydrolysis of the glycogen sample. iii) Calculate the purity of the glycogen used in the sample as % Purity = (moles of measured glucose/ moles of calculated glucose in glycogen) *100 iv) state your answer in a complete sentence.arrow_forwardA 1 mL sample of glycogen was calculated to contain 21 µmol (micromole) glucose. To 1 mL of this sample was added 2 mL of 2 M HCl. It was then hydrolysed by boiling the solution for 15 minutes. After boiling the hydrolysate was cooled and made up with H2O to a final volume of exactly 10 mL. The glucose was measured in this solution and found to have a concentration of 340 µg/mL (microgram/milliliter). i) Calculate the mass (mg) of glucose in the 10 mL of hydrolysate. As the 1 mL of glycogen sample was made up to a final volume of 10 mL, this mass of glucose was produced by the hydrolysis of the original 1 mL glycogen sample. ii) Calculate the amount (µmol) of glucose produced by the hydrolysis of the glycogen sample. iii) Calculate the purity of the glycogen used in the sample as % Purity = (moles of measured glucose/ moles of calculated glucose in glycogen) *100 iv) state your answer in a complete sentence. Show your working out such that the marker can easily understand it.…arrow_forwardExplain the principle behind vacuum distillation.arrow_forward
- Table 1. Solubility Tests. Functional Group Observations (specify type if any) Sample in concentrated (+/-) H2SO4 Color orange Hydroxyl group Hydroxyl group Hydroxyl group 1-butanol Color orange 2-butanol Color orange diisopropyl ether Look at the structures of compounds tested for solubility in concentrated H2SO4. What generalization can be made for a substance to be soluble in concentrated H2SO4 ?arrow_forwardThe followings methods are useful to induce crystallization EXCEPT adding a small crystal of the desired compound, called a seed crystal, to the solution adding anhydrous potassium carbonate to the solution and cooling it in an ice bath scratching the inner wall of the Erlenmeyer flask with a glass stirring rod reheating the solution to boiling to boil off some of the solvent, and then allow the solution to cool to room temperature again to effect crystallizationarrow_forward2. When performing the recrystallization of an impure solid, why is it advised to use the minimal amount of solvent possible? Group of answer choices To minimize the amount of pure solid lost due to its solubility. To minimize the cost of the recrystallization. To reduce the time needed to filter the pure solid from the solvent after recrystallization. To minimize the amount of hazardous materials used.arrow_forward
- 5- A chemist is given a nonelectrolyte white powder for analysis. 38.7 g of this substance is dissolved in 100.0 g of water. It is determined that the resulting solution freezes at -4.0°C. Additionally, the elemental composition of the substance is identified and found to be 40.0% C, 6.7% H and 53.3 % O by mass. Find the molecular formula of this unknown white powder using these experimental evidences (Kf of water: 1.86°C/m, C: 12 g/mol, H: 1 g/mol, O: 16 g/mol).arrow_forwardOral rehydration salts are stated to contain the following components: Sodium Chloride 3.5g Potassium Chloride 1.5g Sodium Citrate 2.9g Anhydrous Glucose 20.0g 8.342 g of oral rehydration salts are dissolved in 500 ml of water. 5 ml of the solution is diluted to 100 ml and then 5 ml is taken from the diluted sample and is diluted to 100 ml. The sodium content of the sample is then determined by flame photometry. The sodium salts used to prepare the mixture were: Trisodium citrate hydrate (C6H5Na3O7, 2H2O) MW 294.1 and sodium chloride (NaCl) NW 58.5. Atomic weight of Na = 23. The content of Na in the diluted sample was determined to be 0.3210 mg/100 ml. Determine the % of stated content of Na in the sample.arrow_forwardOral rehydration salts are stated to contain the following components: Sodium Chloride 3.5g Potassium Chloride 1.5g Sodium Citrate 2.9g Anhydrous Glucose 20.0g 8.342 g of oral rehydration salts are dissolved in 500 ml of water. 5 ml of the solution is diluted to 100 ml and then 5 ml is taken from the diluted sample and is diluted to 100 ml. The sodium content of the sample is then determined by flame photometry. The sodium salts used to prepare the mixture were: Trisodium citrate hydrate (C6H5Na3O7, 2H2O) MW 294.1 and sodium chloride (NaCl) NW 58.5. Atomic weight of Na = 23. The content of Na in the diluted sample was determined to be 0.3210 mg/100 ml. Determine the % of stated content of Na in the sample. The stated should be 104.5, how??arrow_forward
- Chemistry: Matter and ChangeChemistryISBN:9780078746376Author:Dinah Zike, Laurel Dingrando, Nicholas Hainen, Cheryl WistromPublisher:Glencoe/McGraw-Hill School Pub Co