Chapter 20, Problem 18A

Interpretation Introduction

Interpretation:

The major constituents of crude petroleum, natural gas and its preparation are to be written.

Concept introduction:

Crude petroleum and natural gas are non-renewable sources of energy. These are natural sources of energy. These sources should be used in a limited amount so that our future generations can also use these sources.

Answer to Problem 18A

Crude petroleum is a mixture of volatile liquid hydrocarbons.

Natural gas is mainly composed of methane.

Explanation of Solution

Crude petroleum is a mixture of volatile liquid hydrocarbons (compounds composed mainly of hydrogen and carbon), though it also contains some nitrogen, sulphur and oxygen. Almost all crude oil contains 82-87 % carbon by weight and 12-15 % hydrogen by weight. Crude oils are characterized by the type of hydrocarbon it contains as:

• Paraffins
• Naphthene
• Aromatics  

Paraffins are the most common hydrocarbons in crude oil. Naphthene is an important part of all liquid refinery products and the common aromatic in crude oil is benzene.

Crude oil is extracted from underground reservoirs by drilling wells.

Natural gas is mainly form of methane but in addition it contains nitrogen, hydrogen sulphide, carbon dioxide and water. It is formed when layers of dead plants and animals are exposed to heat and pressure under the earth’s surface for many years.

Conclusion

Thus, both crude oil and natural gas are mainly composed of hydrocarbons.