Question

the substances which undergo chemical change are called??????????

Answer 1

The following can indicate that a chemical change has taken place, although this evidence is not conclusive: Change of odor. Change of color (for example, silver to reddish-brown when iron rusts). Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat.

Answer 2

reactants are the substances which undergo reaction
and products are the substances which are formed after any chemical reaction