Refining crude oil into gasoline requires the use of chemicals, pressure, and heat to change the chemical makeup of the crude oil into a finished product of gasoline.

a. True
b. False

 a. True

Explanation:

The three major processes performed to refine crude oil into finished products are separation, conversion or changing and treatment.

In the first step, molecules are separated through atmospheric distillation (i.e. at normal atmospheric pressure), according to their molecular weight. During the process, the crude oil is heated at the bottom of a 60-meter distillation column at a temperature of 350 to 400°C, making it to vaporize. The vapors rise inside the column while the heaviest molecules, or residuals, remain at the bottom. As the vapors rise, the molecules condense into liquids at different temperatures in the column. Only gases reach the top, where the temperature has dropped to 150°C. The liquids, which are become increasingly light the higher they are found in the column, are collected on trays located at different heights of the column. Each tray collects a different petroleum fraction, with highly viscous preservation (hydrocarbons) like asphalt (bitumen) at the bottom and gases at the top of the column.  

There may still be many too heavy hydrocarbon molecules remaining after the separation process. To meet demand for lighter products, the heavy molecules are onverted or cracked into two or more lighter ones. This involves the use of chemical.

The conversion process, which is carried out at 500°C, is also known as catalytic cracking because it uses a substance called a catalyst to speed up the chemical reaction. This process converts 75% of the heavy products into gas, gasoline and diesel. The yield can be increased further by adding hydrogen or by using deep conversion to remove carbon.

Treating involves removing or significantly reducing molecules that are corrosive or cause air pollution, especially sulfur. The purpose of this measure is to improve air quality and optimize the effectiveness of catalytic converters used to treat exhaust gas.