Concept explainers
Interpretation:
The percent of (R)-glyceraldehyde present in the given mixture 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.
Racemic mixture (equal amounts of enantiomers) of a compound has zero specific rotation.
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,
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Chapter 4 Solutions
Organic Chemistry; Modified MasteringChemistry with Pearson eText -- ValuePack Access Card; Study Guide and Student Solutions Manual for Organic Chemistry, Books a la Carte Edition (7th Edition)
- What does chirality mean? What is the difference between diastereomers and enantiomers?arrow_forwardThe specific rotation of (R)-(+)-glyceraldehyde is +8.7. If the observed specific rotation of a mixture of (R)-glyceraldehyde and (S)-glyceraldehyde is +1.4, what percent of glyceraldehyde is present as the R enantiomer?arrow_forwardWhen a crystalline sample of α-glucopyranose is dissolved in water and the specific rotation is measured immediately, the observed rotation is +112°. When the same amount of βglucopyranose is dissolved, the observed rotation is +18.7°. However, over time, at room temperature, both solutions reach a specific rotation of +52.7°. Explain why these two solutions reach the same specific rotation over time.arrow_forward
- The specific rotation of a-D-galactose is 150.7 and that of B-D-galactose is 52.8. When an aqueous mixture that was initially 70% a-D-galactose and 30% B-D-galactose reaches equilibrium, the specific rotation is 80.2. What is the percentage of a-D-galactose and B-D galactose at equilibrium?arrow_forward9 A disaccharide consists of the molecules of D-glucose and D-glucosamine joined by a (1a, 1b)-glucosidic bond. a) Draw the structure of the disaccharide (Haworth projection) if you know that in D- glucose the anomeric carbon has an a-configuration. b) Give the name of the union you drew in question a. c) Draw the structure of the product (cantilever conformation) resulting from the effect of excess acetic anhydride and pyridine on the disaccharide. Hint: D-glucosamine has the same structure as D-glucose, but C-2 has an amino group instead of a hydroxyl.arrow_forwardIf (S)-glyceraldehyde has a specific rotation of -8.7 what is the specific rotation of (R)- glyceraldehyde? O A) -8.7° O B) 0.0° OC) +8.7° O D) cannot be determined from the information givenarrow_forward
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- Vanillin (4-hydroxy-3-methoxybenzaldehyde), the principal component of vanilla, occurs in vanilla beans and other natural sources as a b-d-glucopyranoside. Draw a structural formula for this glycoside, showing the d-glucose unit as a chair conformation.arrow_forwarde Quiz: HW 1: Ch 3: Alkanes AA Quiz: HW 2: Ch 4: Study of Reacti x A Quiz: HW 3: Ch 5: Stereochem A online.butlercc.edu/courses/1479546/quizzes/2495661/take Question 2 If (S)-glyceraldehyde has a specific rotation of -8.7°, what is the specific rotation of (R)- glyceraldehyde? cannot be determined from the information given 0.0° +8.7° -8.7°arrow_forwardIdentify the configuration of the stereogenic center (R or S)arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning