4.1.2. Alkanes

One sp3 orbital from each carbon overlap to form a single C-C bond called a sigma bond

Increasing boiling points of alkanes can be explained by increasing number of electrons in the bigger molecules Increases size of induced dipole-dipole interactions between molecules Longer straight chains have a larger surface area of contact between molecules for London forces to form so have strong induced dipole interactions and higher boiling points

Low reactivity of alkanes with many reagents Due to high bond enthalpies of c-c and c-h bonds Low polarity of sigma bonds

Conversion of large hydrocarbons to smaller molecules by breaking c-c bonds

Petroleum fractions with shorter c chains are in more demand than larger fractions To make use of excess larger hydrocarbons to supply demand for shorter ones Products of cracking more valuable than starting materials

Slight pressure High temperature (450C) Zeolite catalyst used for making motor fuels

UV light homolytic fission - each atom gets one electron from the covalent bond

reactive species which possess an unpaired electron