Texas CNG(Compressed Natural Gas) Driver Practice

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Prepare for the Texas CNG Driver Test with comprehensive quizzes and detailed explanations. Get equipped with essential knowledge to ace your certification exam efficiently!

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What is primarily contained in compressed natural gas?

A mix of gases and vapors
Hydrocarbons, mostly ethane
Hydrocarbons, consisting principally of methane
Only carbon dioxide and hydrogen

The correct answer is: Hydrocarbons, consisting principally of methane

Compressed natural gas is primarily composed of hydrocarbons, with methane being the main component. Methane (CH4) comprises about 70-90% or more of CNG, making it the dominant substance contained within the gas. This high concentration of methane is what allows CNG to be an efficient fuel source, as it combusts cleanly, emitting fewer pollutants compared to other fossil fuels. While there may be minor amounts of other hydrocarbons in CNG, such as ethane, propane, and butane, these make up a much smaller fraction of the overall composition. The presence of these additional gases does not significantly alter the fact that methane is the principal constituent. Therefore, the answer that identifies CNG as consisting principally of methane accurately reflects the composition of this fuel. The other options mentioned either suggest a composition that signifies a wider variety of gases without acknowledging methane's dominance, or incorrectly define CNG's components by excluding methane or including gases that are not primarily present in CNG. Thus, identifying methane as the main component offers a clear understanding of what compressed natural gas is made up of and its implications for use as a fuel source.