A welding torch produces a flame by burning acetylene fuel in the presence of oxygen. This flame is used to melt a metal. Which energy transformation represents this process?

Burning acetylene releases energy stored in its chemical bonds. That energy heats the flame, so the main transformation is chemical energy into thermal energy. The thermal energy then melts the metal, making choice C, “chemical energy into thermal energy,” correct.

AI-written and checked against the verified answer.