Question

question #4

Prelab Question #1: (answer the three prelab questions on this printed handout; this question is 2) related to polarimetry of Limonene): A student dissolves 0.20g of pure R-Limonene in a total of 5 mL of ethanol using a volumetric flask. The student fills a 2 dm polarimetry tube with this solution and observes a rotation of + 8.2° from that sample. Calculate the specific rotation of the student's sample of R-Limonene. 102.5 Formula to use: [a] = 1075 ב<סניס lx c 020Ks [a] specific rotation at 589 nm observed degrees of rotation at 589 nm (is either positive or negative valuc) length of the sample tube in decimeter (Recall that 10 cm- 1 dm) concentration of the sample in grams per'mL C Prelab Question # 2 : Calculate the % ee of this student's solution 3) given the equation below and the fact that the expected [a] for R- Limonene is 125.6°. 02.5 observed [a] x100 expected [a] % ee /.00.10 95.G X 4) Prelab Question #3: Calculate the ratio of R and S enantiomer present given the equation below. R refers to the percentage present as the R enantiomer, while S refers to the percentage present as the S enantiomer. R-S x100 R+S R+S-1 % ee = and

Answer 1

81.6.6. ee of R-enationer 100-81.66 = f en Racemic - 18.4 mixture racena mixture. 9.2% R- 9:21 S- Total R-enantiomer = 81.61.+9.2%. = 90.61 Total S- enantioner = 19.21.] .: Ratto; -90. = 19.87 us