Interpretation:
The percent of each enantiomer in the given solution has to be calculated.
Concept introduction:
The pair of Enantiomers has different configurations.
Pair of enantiomers has different optical activity, which means if one will show levorotatory then the other will show dextrorotatory.
The direction and magnitude of rotation of plane-polarized light by an optically compound is measured by using polarimeter.
This rotation of polarized light is specific for a compound at specified temperature and wavelength, so it is called as Specific rotation of that compound.
The specific rotation of enantiomers has equal magnitudes and opposite signs.
Specific rotation of compound is calculated by,
If the mixture contain unequal amount of enantiomers of a compound, then the amount of excess of enantiomer is called enantiomeric excess or optical purity. It is calculated by,
Trending nowThis is a popular solution!
Chapter 4 Solutions
MASTERING ORGANIC CHEMISTRY W/ETEXT >I
- A pure sample of the R isomer of a particular compound is known to have a specific rotation of -40. A mixture of the two enantiomers of the compound gives a specific rotation of +8. What are the percentages of the S and R enantiomers in the mixture?arrow_forwardA 0.26 M solution of an enantiomerically pure chiral compound D has an observed rotation of +0.197° in a 1‑dm sample container. The molar mass of the compound is 132.3 g/mol. a. What is the specific rotation of D? b. What is the observed rotation if this solution is mixed with an equal volume of a solution that is 0.26 M in L, the enantiomer of D? c. What is the observed rotation if the solution of D is diluted with an equal volume of solvent?arrow_forwardA sample mixture containing the made-up enantiomers (R)-(+)-Nenanoic acid and (S)-(-)-Nenanoic acid has an apparent specific rotation of +25.12° at 25 °C. This solution has an enantiomeric excess (EE) of 74.0%. Provide answers to the following questions 1.What percentage of the sample described above is (S)-(-)-Nenanoic acid? 2.What is the apparent specific rotation of a sample composed of 80.0% (R)-(+)-Nenanoic acid and 20.0% (S)-(-)-Nenanoic acid?arrow_forward
- A sample mixture containing the made-up enantiomers (R)-(+)-Nenamide and (S)-(-)-Nenamide has an apparent specific rotation of +6.50° at 25 °C. This sample has an enantiomeric excess (EE) of 43.0%. Provide answers to the following questions : 1.Which enantiomer is in excess in the sample? 2.What is the specific rotation of (S)-(-)-Nenamide?arrow_forwardGlutamic acid is a naturally occurring amino acid and isthe precursor to the food additive MSG (monosodium glutamate)which can cause allergic reactions in some people. If naturally occurring L glutamic acid has a melting point of 205 C and an optical rotation of + 31.5, what is the melting point and optical rotation of its enantiomer?arrow_forwardSuppose a solution of a compound gave a rotation of +160o. How could this rotation be distinguihed from one of -200oand from one of +520o?arrow_forward
- When 1 g of compound X is dissolved in 100 mL of solvent, the observed rotation is +12. What will be the observed rotation if 1 g of compound X is dissolved in 200 mL of solvent?arrow_forwardGlutamic acid is a naturally occurring amino acid and is the precursor to the food additive MSG (monosodium glutamate) which can cause allergic reactions in some people. If naturally occurring L glutamic acid has a melting point of 205 C and an optical rotation of + 31.5, what is the melting point and optical rotation of its enantiomer?arrow_forwardThe specific rotation of (R)-2-chlorobutane is -9.0 degrees. If 2.92 g of its enantiomer is dissolved in 6 mL of ether and placed in a sample cell with a length of 1.0 dm, what observed rotation do you expect (write answer with two decimal places)?arrow_forward
- A solution prepared by mixing 10 mL of a 0.10 M solution of the R enantiomer of a compound and 30 mL of a 0.10 M solution of the S enantiomer was found to have an observed specific rotation of +4.8. What isthe specific rotation of each of the enantiomers? (Hint: mL * M = millimole, abbreviated as mmol)arrow_forwardThe observed rotation of a solution of 1.2 g of a compound in 10 mL of water is +0.75 degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?arrow_forwardThe specific rotation of (S)-carvone (at 20 degrees) is +61. A chemist prepared a mixture of (R)-carvone and its enantiomer, and this mixture had an observed rotation of -55. (a) What is the specific rotation of (R)-carvone at 20 degrees? (b) What percentage of the mixture is (S)- carvone? Choose from the following options. 1. 90% (S)-carvone and 10% (R) 2. 10% (S)-carvone and 90% (R) 3. 95% (S)-carvone and 5% (R) 4. 5% (S)- carvone and 95% (R)arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningEBK A SMALL SCALE APPROACH TO ORGANIC LChemistryISBN:9781305446021Author:LampmanPublisher:CENGAGE LEARNING - CONSIGNMENT