Organic Chemistry College help

Question

Im so lost on how to go about or even start these.

Draw structures for the following organic compounds:

a) 1,1,2-trichlorobutane

b) 3-ethyl-2,4,5-trimethyloctane

c) 1,3-butadiene

d) 1,2-pentadiene

thank you

Answer 1

1,1,2-trichrolo-butane:

Cl Cl H H

Cl C - C -C -C H

H H H H

4 carbons in a line. 1st carbon has 2 Cl's and 1 H;

2nd carbon has 1 Cl and 1 H

3rd carbon has 2 H's

4th carbon has 3 H's

name the backbone : butane for 4 carbons; numbers are carbon number that each subitution for hydrogen is on.

3-ethyl-2,4,5-trimethyloctane

C - C

|

C - C - C - C- C - C - C- C

| | |

C C C

I did not put in all of the hydrogens in the drawing.

a terminal carbon has three hydrogens and middle carbons have enough H's to give them 4 bonds. The ethyl group is H₃C-CH₂-; and the methyl group is H₃C. The numbers are for the carbon order that the substitute groups are on.

1,3-butadiene:

H H

H₂ C = C - C= CH₂

ene is for a double bond; the numbers are for the placements of the double bonds. Buta means four carbons

1,2- pentadiene: 1,2 pentadiene would not exsist due to molecular bond strain. A molecule must have a least one single bond between two double bonds.

1,3 -pentadiene would be similar to 1,3 butadiene with the 1st and 3rd bonds being double.

1,4-pentadiene and 2,4 also exist.

Penta means 5 carbons in a row.

Numbering is always in the order as being the lowest numbers as possible.