🔍 Key Concepts

• Chemical composition of fuel oil and how it relates to energy released during combustion • Role of combustible vs. non-combustible elements in producing heat • Which elements in the choices typically add energy, and which ones tend to dilute or reduce heat value

💭 Think About

• Which of the listed constituents actually burns to release heat, and which are mostly inert or even undesirable in fuel? • Think about which element(s) you want more of in a fuel if you want a higher calorific (heat) value. • For each option, ask yourself: does this mainly contribute to energy, pollution, or is it mostly non-reactive in combustion?

✅ Before You Answer

• Identify which option represents the primary combustible content of fuel oil. • Recall that high heat value fuels have a high proportion of burnable material and a low proportion of impurities. • Check which constituents in the list are usually considered impurities or pollutants rather than useful energy carriers.