Would you expect two enantiomers such as (R)-2-bromobutane and (S)-2-bromobutane to have identical or different IR spectra? Explain.

Which of the following complexes can exist as enantiomers? Draw the structure of both enantiomers.
(a) $\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$
(b) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4(\mathrm{en})\right]^{3+}$
(c) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_2(\mathrm{en})_2\right]^{3+}$
(d) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right]^{+}$

Which of the following are chiral and, therefore, capable of existing as enantiomers? (a) 1,3- Dichlorobutane (b) 1,2- Dibromopropane (c) 1,5 -Dichloropentane (d) 3 -Ethylpentane (c) 2 -Bromobicyclo [1.1 .0] butane (f) 2 -Fluorobicyclo [2.2 .2] octane (g) 2-Chlorobicyclo[2.1.1]hexane (h) 5-Chlorobicyclo[2.1.1]hexane

The number of bacteria in the Petri dish, N, is given by the equation N= 3t^2 + $\frac {2}{3}$ t + 50, where t is time in hours since the bacteria were introduced to the Petri dish.

A) Draw this function to show one full day of growth.

B) How many bacteria were introduced at the start of the experiment?

C) How many bacteria were there, after one hour?

D) How long does it take the bacteria population to reach 1000?

a. Are d-erythrose and l-erythrose enantiomers or diastereomers?

b. Are l-erythrose and l-threose enantiomers or diastereomers?

Draw the structures of all possible diastereoisomers of an octahedral complex with the formula $\mathrm{MA}_2 \mathrm{B}_2 \mathrm{C}_2$. Which of the diastereoisomers, if any, can exist as enantiomers?

Although one enantiomer of the drug thalidomide is a sedative, the other is teratogenic (causes birth defects). Unfortunately, thalidomide is racemized in the body and, for that reason, both enantiomers are teratogenic. Assuming the availability of acids and bases as needed, give a curved-arrow mechanism for the base-catalyzed racemization of thalidomide in water.

Give a structure for an optically inactive compound $A$ $\left(\mathrm{C}_6 \mathrm{H}_{10} \mathrm{O}_4\right)$, that can be resolved into enantiomers and has the following NMR spectra: ${ }^{13} \mathrm{C}$ NMR: $\delta 13.5, \delta 41.2, \delta 177.9$ proton NMR: $\delta 1.13(6 H, \mathrm{~d}, J=7 \mathrm{~Hz}) ; \delta 2.65$ ( $2 H$, quintet, $J=7 \mathrm{~Hz}) ; \delta 9.9\left(2 \mathrm{H}\right.$, broad s, disappears after $\mathrm{D}_2 \mathrm{O}$ shake)

Give the structure of an isomer of compound A that has a different melting point than A and NMR spectra that are almost identical to those of A.

Explain the meaning of enantiomers

Only three stereoisomers are possible for 2,3-dibromo-2, 3-dichlorobutane. Draw them, indicating which pair are enantiomers. Why does the other isomer not have an enantiomer?

The following reactions give a mixture of two stereoisomers. Write their structures. Are they enantiomers or diastereomers? Are they chiral or achiral? Are they formed in equal amounts?

(a) $\mathrm{BrCH}_2 \mathrm{CH}_2 \mathrm{Br}+\mathrm{Cl}_2 \stackrel{\text { light }}{\longrightarrow} \mathrm{C}_2 \mathrm{H}_3 \mathrm{Br}_2 \mathrm{Cl}+\mathrm{HCl}$

(b) CC1CCC(C)(O)CC1

$$\stackrel{\mathrm{HCl}}{\longrightarrow}$$

(c) CC1(C)CCCC(C)(O)C1

$$\stackrel{\mathrm{HCl}}{\longrightarrow}$$

Both enantiomers and diastereomers are stereoisomers. How do they differ?

Define each of the following words: a. ostomy b. suppository c. fecal impaction d. enema e. enema

Which molecule can have enantiomers?

(A) CH$_4$

(B) CF$_2$H$_2$

(C ) CFCIBrI

(D) CF$_2$CIH