What percentage of heating oil comprises carbon?

Heating oil is primarily derived from petroleum and is predominantly composed of hydrocarbons. When we consider the composition of these hydrocarbons, it is important to note that carbon is a significant component due to its presence in the molecular structure of these compounds.

The correct answer, which suggests that 85% of heating oil is carbon, aligns with the understanding of the typical chemical makeup of heating oil. Generally, the carbon content in heating oil is high because hydrocarbons are primarily made up of carbon and hydrogen atoms. Although some variations exist based on the specific formulation of the heating oil and its additives, 85% is a recognized and commonly accepted approximation for the carbon composition.

In comparison, the other options present levels that are either too low or too high for heating oil's carbon content based on standard industry knowledge. For instance, values like 70% or 80% do not adequately capture the substantial carbon presence in heating oil, while 90% is slightly above what is typically observed. This highlights why 85% is the most accurate estimate for the carbon percentage in heating oil.