18. C-2 is the chiral center.
21. Yes, they are the non-superimposable mirror images of each other, hence they fit the criteria for optical isomers.
22. The mirror images of glyceraldehyde can be drawn as follows.

glceraldehyde molecule glyceraldehyde molecule IV. Using Models of Compounds with One Chiral Center 17. Use your...
V Using Models of Compounds with Two Chiral Centers 25. On your drawing, use arrows to indicate the at- oms that could be chiral centers (34). 23. Construct a model of 2,3,4-trihydroxybutanal, as shown in Figure 4 26. Make a template for the atoms attached to carbon 2 in the molecule. The groups of atoms attached to carbon 2 may not touch the paper, but you can still mark their relative positions (35). OH OH HI H-C C aC 27....
3. Diastereomers and Meso Forms. When a molecule has two or more stereogenic centers, stereoisomers that are not mirror images can exist; these are called diastereoisomers. Within this general class, there are special types of stereoisomers that are always optically inactive and are called meso forms. Construct a model with four different colored balls about a carbon center. Construct another identical to the first and verify this by the superimposition test. Now remove the same colored balls, blue (C from...
3. Diastereomers and Meso Forms. When a molecule has two or more stereogenic centers, stereoisomers that are not mirror images can exist; these are called diastereoisomers. Within this general class, there are special types of stereoisomers that are always optically inactive and are called meso forms. Construct a model with four different colored balls about a carbon center. Construct another identical to the first and verify this by the superimposition test. Now remove the same colored balls, blue (C from...
19-26 thanks!
19-29*
PART 3: 2,3-BUTANEDIOL CH-CH(OH)-CH(OH)-CH, mirror images, not superimposable Build as many models of 2,3-butanediol as you can. First, attach two carbons with a single bond. To each carbon add one carbon, one hydrogen, and one oxygen. To complete the structure, Ti the remaining hydrogen atoms. Remember, a model is not different if it is completely superimposable on one already constructed! 13. How many stereochemically different models are possible for 2,3-butanediol? 14. What characteristic does one of these...
3. Cyclic compounds The presence of the ring in all but very large ring cyclic molecules prevents full rotation of the ring atoms. For this reason, stereoisomerism may also occur in cyclic molecules. a) Prepare a model of cyclohexane, C6H12. Draw the condensed formula. b) Build a model of methylcyclohexane (C7H14) by replacing one of the hydrogens of cyclohexane with a methyl group. Draw the skeletal formula for methylcyclohexane. 2 c) How many different isomers exist for methylcyclohexane (CyH34)? d)...
In this problem, how do you know which atoms or groups are
going away, towards you, or in plane from the chiral center? for
example, why do they assume that hydrogen is going away (dotted
line) and Ch3 is coming towards you (bold colored line)? And how do
you know which direction Ch2Ch2Br and Br is going in? its just a
single line (Not dotted or bold). I know directions are important
in determining R/S.
Ex: In the second photo...
A. Enantiomers: Certain substances have the unique property of rotating the plane of plane-polarized light. Such light rotation is detectable with the aid of a polarimeter. In order for a molecule to be optically active it must be chiral. Chiral objects lack a plane of symmetry and are non-superimposable on their mirror images. A sp?- hybridized carbon atom can fulfill these requirements if all four of its substituents are different. 1. Methane a) Prepare a methane molecule and then substitute...
Questions 7-15 The molecule is ethane
71 2 O ACTIVITY 1.2.1 Biological Macromolecules in 3-D 7. Orient the two molecules so that portions of the mo lecules that would normally form intermolecular bonds lie next to each other. In this activity, you will build molecular models of biologically important molecules using ball-and-spring molecular model 1) What intermolecular forces help to hold these mo- building kits and then you will view these and other molecules lecules together! of interest using computer-generated...
e. 18 Test Your Knowledge MULTIPLE CHOICE: Choose the one best answer. 1. Each element has its own characteristic atom in which a. the atomic mass is constant. b. the atomic number is constant. c. the mass number is constant. d. Two of the above are correct. e. All of the above are correct. 2. Which of the following is not a trace element in the human body? a. iodine b. zinc c. iron d. calcium e. fluorine 3. A...