Question

hypothesis: if a material undergoes a chemical change, then it will not retain its original properties because a new substance is formed.
to test the hypothesis above, you will observe the changes during the experiment.
to do this, you will use these observations to compare the
of the substances
to the
of the substances.
done

Explanation:

The goal is to test if a chemical - change results in loss of original properties. So, one should compare the properties of substances before (original state) and after (new - formed state) the chemical change.

Answer:

properties before the chemical change; properties after the chemical change