Question

which two facts are about a chemical change? the change cannot be reversed. the substance changes size or shape but remains the same substance. the change results in a new substance. it is usually possible to change the substance back.

Explanation:

A chemical change results in a new substance and is often irreversible. Changing size or shape is a physical change, and chemical - changes are not easily reversed.

Answer:

The change cannot be reversed.
The change results in a new substance.