Katrin chops wood for a fire. She places the logs in the fireplace and sets one on fire. She watches as all the logs begin to burn, creating ash in the fireplace. Katrin is warmed by the fire.

Question

What evidence shows that a chemical change has happened in this example?

Select all that apply.

Responses

the wood is chopped
the wood is chopped

ash, a new substance, forms
ash, a new substance, forms

wood is set in the fireplace
wood is set in the fireplace

the temperature changes
the temperature changes

Answer 1

The evidence that shows a chemical change has happened in this example includes:

• ash, a new substance, forms: This indicates a chemical change as the wood has transformed into a different substance (ash) during the burning process.

• the temperature changes: The production of heat (warming Katrin) is a typical sign of a chemical change, as energy is released when the wood combusts.

The other options (the wood is chopped and the wood is set in the fireplace) do not indicate a chemical change; they are physical changes or actions related to the preparation of the wood for burning.