The bigger the substituent, the more it is slowed down. Cis -Trans Isomerism Cis and trans isomers are molecules which have the exact same atomic attachments, but different arrangements of atoms in space. For two identical substituents on cyclopentane, two possible arrangements exist. These isomers can not be interconverted without breaking bonds. Therefore these are two distinct molecules with their own unique physical and chemical properties.
Similar isomers are possible for cyclopropane and butane.
Isomerism Chemical Reactions of Alkanes Combustion and Oxidation - alkanes in the form of various petroleum products are used as fuel to produce heat by burning in air. Depending on the precise conditions of reaction, i.e. amounts of each reactant, temp., pressure, etc. This reaction requires a catalyst of heat or light. No reaction will take place in the absence of light or heat. If sufficient halogen is present the reaction will proceed to replace additional H's with a halogen until eventually they will all be replaced.