G2 Gas Fitter Practice Exam

What are the two main hydrocarbons that form natural gas?

1. Propane and Butane

2. Hexane and Heptane

3. Methane and Ethane

4. Octane and Nonane

The correct answer is: Methane and Ethane

The primary constituents of natural gas are methane and ethane. Methane, with the chemical formula CH₄, is the most abundant component, accounting for approximately 70-90% of natural gas. Ethane, with the formula C₂H₆, is typically present in smaller amounts, contributing to the energy content of the gas and influencing its combustion properties. Commercial natural gas typically consists of a mixture of various hydrocarbons, but methane is the key fuel component, which is why it is often considered the main component. Ethane, while not as prevalent as methane, is still significant in the composition of natural gas and is often included in discussions about its constituents. Understanding these two hydrocarbons helps clarify why they are crucial in natural gas applications, including heating, cooking, and electricity generation. The other hydrocarbon options, such as propane, butane, hexane, heptane, octane, and nonane, are either heavier hydrocarbons or not typically found in significant amounts in natural gas. They are more relevant in discussions of liquefied petroleum gas (LPG) or other fuel types rather than natural gas itself.