Question

When a sugar cube is placed in a pan on a hot stove, the sugar melts, the sugar burns and produces smoke, the sugar cube changes shape, and the air around the pan heats up. Which of these is an example of a chemical change?
Responses
A the sugar meltsthe sugar melts
B the sugar burns and produces smokethe sugar burns and produces smoke
C sugar cube changes shapesugar cube changes shape
D and the air around the pan heats up

Answer 1

B — the sugar burns and produces smoke.

Burning is a chemical change because the sugar reacts with oxygen to form new substances (gases, ash) and releases energy. Melting and a change of shape are physical changes, and warming the air is a physical change (temperature increase).