The specific rotation for (-)-methylphenidate is -38° mL g¹ dm¯1. Path length of the polarimeter is 1 dm. -1 You dissolve 0.5 g of a mixture of (-)-methylphenidate and its enantiomer in 4 mL of water. You place the sample into a polarimeter and the observed rotation is found to be -0.2°. What percent of the mixture is composed of (-)- methylphenidate? (Round your answer to the nearest whole percent.) The numerical values in this calculation will change with each attempt. Double check before submitting additional attempts.

The specific rotation for (-)-methylphenidate is -38° mL g¹ dm¯1. Path length of the polarimeter is 1 dm. -1 You dissolve 0.5 g of a mixture of (-)-methylphenidate and its enantiomer in 4 mL of water. You place the sample into a polarimeter and the observed rotation is found to be -0.2°. What percent of the mixture is composed of (-)- methylphenidate? (Round your answer to the nearest whole percent.) The numerical values in this calculation will change with each attempt. Double check before submitting additional attempts.

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter3: Stereoisomerism And Chirality

Section3.7: Optical Activity—how Chirality Is Detected In The Laboratory

Problem 3.9P

See similar textbooks

Similar questions

When 0.075g of penicillamine is dissolved in 10.0 mL of pyridine and placed in a sample cell 10.0 cm in length, the observed rotation at 20 degrees (using the D line of sodium) is -0.47 degrees. Calculate the specific rotation of penicillamine. a. (-0.47)/[(0.075g/mL) (1.00 dm)]= -6.3 b. (0.47)/[(0.075g/mL) (1.00 dm)]= 6.3 c. (-0.47)/[(0.0075g/mL) (1.00 dm)]= -63 d. (0.47)/[(0.0075g/mL) (1.00 dm)]= 63
A 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?
When 0.018 g of cholesterol is dissolved in 1.00 mL of ether and placed in a sample cell 10.0 cm in length, the observed rotation at 20 degrees (Using the D line of sodium) is -0.0567 degrees. Calculate the specific rotation of cholesterol. specific rotation= [α] =
(-)-Cholesterol has a specific rotation of -32o. A mixture of (+)- and (-)-cholesterol was analyzed by polarimetry, and the observed rotation was 14o. What is the percent composition of the (+) isomer in this mixture?Assume 1 g of sample was dissolved in 1 mL water and the sample cell was 1 dm long.
7. A 0.5 gram sample of hoodia gordonii isolated from natural sources yields an observed rotation of -0.76° when dissolved in 20 mL of chloroform and placed in a 1-dm cell. Determine the specific rotation [α] of hoodia gordonii for: (a) the entities as defined above,(b) an increase in solute from 0.5g to 1.0 g;(c) an increase in solvent from 20 mL to 40 mL; and (d) an increase in path length from 1 dm to 2 dm. Does entities defined above refer to the picture since its a hoodia gordnii? I don't even know where to start with this one
1. When 0.247 g of monosodium glutamate (MSG) is dissolved in 10.0 mL of water and placed in a sample cell 10.0 cm in length, the observed rotation at 20°(using the D line of sodium) is +0.632°. Calculate the specific rotation of MSG. 2. When 0.095 g of cholesterol is dissolved in 1.00 mL of ether and placed in a sample cell 10.0 cm in length, the observed rotation at 20°C (using the D line of sodium) is -0.299°.Calculate the specific rotation of cholesterol.3. The specific rotation of L-dopa in water (at 15°C) is -39.5. A chemist prepared a mixture of L-dopa and its enantiomer, and this mixture had a specific rotation of -34. Calculate the % ee of this mixture. 4. The specific rotation of vitamin B7 in water (at 22°C) is +92. A chemist prepared a mixture of vitamin B7 and its enantiomer, and this mixture had a specific rotation of +18. Calculate the % ee of this mixture.
1. A solution of (S)-2-butanol (molar mass = 74.12) is observed to have a rotation in a 10 cm path length of +16.2 degrees. If the molar specific rotation of (S)-2-butanol is +135.2 degrees, what is the concentration of (S)-2-butanol in grams per liter? 2. After an attempt to resolve a racemate into its enantiomers, the observed rotation is +22.4 degrees per g/L. If the known specific rotation is +24.2 degrees per g/L,, what is the % enantiomeric excess of the compound? 3. If the % enantiomeric excess of a chiral compound is 88.2%, what is its chiral purity?
The specific rotation of (-) isomer is -22˚, with concentration of 4.2 g/100 mL, and pathlength of 0.5 dm. The specific rotation of (+) isomer is +17.4˚, with concentration of 4.0 g/100 mL, and pathlength of 0.5 dm. 1. Calculate the observed rotation of the (+) and (-) methylbenzylamine isomers, and explain that the polarimeter calculates the specific rotation 2. calculate %ee (enantiomeric excess) (allows for further discussion; attention to be paid to the accepted optical rotation to ensure that it is in the same particular solvent system)
A solution of 0.50 g of (-)@epinephrine dissolved in 10.0 mL of diluteaqueous HCl was placed in a 20-cm polarimeter tube. Using the sodium D line, the rotation was found to be -5.1° at 25 °C. Determine the specific rotation of epinephrine.
An aqueous solution containing 10 g of an optically pure compound was diluted to 500 mL with water and was found to have a specific rotation of −121º. If this solution were mixed with 500 mL of a solution containing 3 g of a racemic mixture of the compound, what would the specific rotation of the resulting mixture of the compound? What would be its optical purity?
The specific rotation of (R)carvone is -61o. A chemist prepared a mixture of (R)-carvone and (S)-carvone, and the mixture had an observed rotation of -47o. What is the % enantiomeric excess (ee) of the mixture?
If we measure the rotation angle of a sample in a polarimeter and it is zero, the sample….(1). It is a 1.00 M aqueous solution of a pure substance of rotational power exactly equal to 100.(2). It is optically inactive.(3). It is an equimolar mixture of enantiomers of the same compound.(4). It is a mixture of right-handed and left-handed substances.