rank the following compounds according to their heat of combustion. compound compound name heat of…

rank the following compounds according to their heat of combustion. compound compound name heat of combustion 2 - methylheptane select 2 - methylhexane select nonane select octane select

rank the following compounds according to their heat of combustion. compound compound name heat of combustion 2 - methylheptane select 2 - methylhexane select nonane select octane select

Answer

Explanation:

Step1: Recall heat - of - combustion principle

The heat of combustion of hydrocarbons increases with the number of carbon atoms. For isomers, the more branched - out isomer has a lower heat of combustion due to greater stability.

Step2: Count carbon atoms

Nonane ($C_9H_{20}$) has 9 carbon atoms, octane ($C_8H_{18}$) has 8 carbon atoms, 2 - methylheptane ($C_8H_{18}$) has 8 carbon atoms, and 2 - methylhexane ($C_7H_{16}$) has 7 carbon atoms.

Step3: Compare isomers

Among octane and 2 - methylheptane (both with 8 carbon atoms), 2 - methylheptane is branched and more stable, so it has a lower heat of combustion than octane.

Answer:

Nonane > Octane > 2 - methylheptane > 2 - methylhexane