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ID: 496804 • Letter: A
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Attempts Score 95 10 98 100 100 95 15 95 16 95 17 100 000 31 20 100 21 93 22 95 23 100 Ask me anything e 3/16/2017 11:55 PM A 91.2/100 G 3/16/2017 01:08 PM Gradebook Calculator Periodic Table Question 19 of 30 ncorrect ncorrect ncorrect Map A A 0.130 M solution of an enantiomerically pure chiral compound D has an observed rotation of +0.24" in 1-dm sample container. The molar mass of the compound is 154.0 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 0.130 M in L, the enantiomer of D? Number deg mL 6.99 Number g dm deg (d) What is the specific rotation of D (c) What is the observed rotation if the solution of Dis diluted with an equal volume of solvent? after the dilution described in part (o)? Number Number deg mL 0.12 deg 6.99 g dm (f) What is the observed rotation of 100 mL of a (e) What is the specific rotation of L, the enantiomer of solution that contains 0.01 mole of D and 0.005 mole of L? (Assume a 1-dm pat D, after the dilution described in part (c)? Number Number deg mL 0.12 deg 6.99 g dm Previous Give Up & View Solution Check Answer € Next Exit HintExplanation / Answer
a] Observed rotation = Specific rotation *length*Concentration
Specific rotation = Observed rotaion / length *concentration
Specific rotation = 0.24 / 1*0.13 = + 1.846 deg *L / Moles* dm
1.846*1000 / 154 = 11.988 deg*ml / g*dm
b] same concentration of 0.13 M in L gives rotation equal and opposite to D
That is eqaul to - 0.24 deg
Answer is 0.24 - 0.24 = 0
c] IF solution is diluted with same amount of volume
Then concentration becomes half so observed rotation becomes half of the original
Observed rotation = 0.2 /2 = + 0.12 deg
d] Specific rotation = + 0.12 *1000 / 1*0.065 *154 = 11.988
C = 0.13/2 = 0.065 M
ANswer is 11.988
e] it will be negative of D ==> -11.988
f] 100 ml of 0.1 mole of D and 0.005 moles of L
Specific rotation of D = 1.846 deg / M*cm
0.1*1.846 / 100*10^-3 + 0.005*(-1.846) / 100*10^-3 = + 1.75 deg
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