Question

when a candle burns, soot forms on a knife held over it. which indication of change does the soot demonstrate? gas bubbles form during the process. a new solid forms as the candle burns. the knife is being dissolved by fire.

Explanation:

When a candle burns and soot forms on a knife held over it, a new substance (soot - a solid) is created through a chemical reaction. This is an indication of a chemical change as new substances are formed during chemical reactions. The first option about gas bubbles forming is not relevant here as there is no mention of gas - bubble formation in the described scenario. The third option about the knife being dissolved by fire is incorrect as the knife is not being dissolved; rather, soot is depositing on it.

Answer:

A new solid forms as the candle burns.