$1.$ The classification of crude oil is primarily based on its $\_\_,$ content, and $\_\_,$ which affect its refining process and market value.

$2.$ In the desalting process of crude oil, water is used to remove $\_\_,,$ and other impurities before the oil undergoes further $\_\_.$

$3.$ Crude oil stabilization aims to remove $\_\_$ components, such as and $\_\_,$ to prevent issues during storage and transportation.

$8.$ Atmospheric distillation units operate at $\_\_$ pressure to separate crude oil into lighter fractions such as and $,$ whereas vacuum distillation units process heavier fractions under $\_\_$ conditions.