Question

15.Many observations can be made of a burning candle. Which of the following observations indicate that a chemical change has occurred?Select one:a. Wax drips down the side of the candle and hardens.b. Wax forms a pool around the wick.c. The wick turns into a black powder.d. The shape of the flame varies when wind currents change.

Answer 1

c. The wick turns into a black powder.

Step-by-step explanation

When a candle burns, the oxygen in the air reacts and forms carbon dioxide. A new substance (black powder), CO2 is formed. So it is a chemical change. When the candle melts, no new substance is formed and the molten wax can be again solidified and made into a candle and it is a reversible change.

The only observation in the given options that indicate that a chemical change has occurred is:

c. The wick turns into a black powder.