Chem 3.5 answers #2

CHEMISTRY 3.5 ANSWERS

WORKSHEET TWO ORGANIC Isomerism

1. Isomers have the same molecular formula but different structural formula.

2. pentane 2-methylbutane

2,2-dimethylpropane (dimethylpropane)

3. but-1-ene but-2-ene

2-methylpropene

4. propanal propanone

5. (a) The molecule will have a chiral carbon atom, ie a carbon atom with four different groups on it.

(b) Two enantiomers have identical chemical properties, but in biochemical systems they behave differently. They also have the same physical properties except for their effect on plane-polarised light. One enantiomer will rotate the plane of polarisation clockwise and the other anticlockwise.

(c) Many biological molecules such as amino acids are optically active. Often only one of the isomers is able to function properly in living things.

6. (a) (b)

7. (a) NH2CH2CH2CH2CH(CH3)COOH

(b) CH3CHClCH2CHClCH2CH3

(c) CH3CHO

(d) CH3CH2CHBrCH3

(e) (CH3)2CHCH(CH3)COOH

(f) Any of the above arranged as in answer 6(a) above.

CH3CH2CH2CH2CH3 CH3CH(CH3)CH2CH3

CH2CHCH2CH3 CH3CHCHCH3

CH2C(CH3)CH3

CH3CH2CHO CH3COCH3

C

CH3CH2

HCl

CH3

C

CH3CH2

ClH

CH3

CH3CHCHH2C

CH2 CH3

CH3 C(CH3)2CH3