Question

question two (organic chemistry) 10 marks draw the condensed structural formula of 3 -ethyl-2,4,5 -trimethylheptane and 1 -isopropyl-3 -methylcyclohexane. 2 draw all the name the four possible structures for the compounds with the formula c4h8. 8

Explanation:

Step1: Draw 3 - ethyl - 2,4,5 - trimethylheptane

The parent chain is heptane (7 - carbon chain). At the 3 - position, there is an ethyl group ($-CH_2CH_3$), and at the 2, 4, and 5 positions, there are methyl groups ($-CH_3$). The condensed structural formula is $CH_3CH(CH_3)CH(C_2H_5)CH(CH_3)CH(CH_3)CH_2CH_3$.

Step2: Draw 1 - isopropyl - 3 - methylcyclohexane

The parent ring is cyclohexane. At the 1 - position, there is an isopropyl group ($-CH(CH_3)_2$) and at the 3 - position, there is a methyl group ($-CH_3$). The condensed structural formula is $C_6H_{10}(CH(CH_3)_2)(CH_3)$ where the $C_6H_{10}$ represents the cyclohexane ring with two substituents.

Step3: Find possible structures for $C_4H_8$

1. But - 1 - ene: $CH_2=CHCH_2CH_3$.
2. But - 2 - ene: $CH_3CH = CHCH_3$ (exists as cis - and trans - isomers).
3. Methylcyclopropane: A three - membered ring with a methyl group attached to one of the carbon atoms of the ring, $C_3H_5(CH_3)$.

Answer:

1. Condensed structural formula of 3 - ethyl - 2,4,5 - trimethylheptane: $CH_3CH(CH_3)CH(C_2H_5)CH(CH_3)CH(CH_3)CH_2CH_3$
2. Condensed structural formula of 1 - isopropyl - 3 - methylcyclohexane: $C_6H_{10}(CH(CH_3)_2)(CH_3)$
3. Possible structures for $C_4H_8$: But - 1 - ene ($CH_2=CHCH_2CH_3$), But - 2 - ene ($CH_3CH = CHCH_3$), Methylcyclopropane ($C_3H_5(CH_3)$)