Question

All the following are signs of a chemical reaction, except



A. a change in color or odor.
B. a release of gas.
C. a change of state.
D. a change in energy.

Answer 1

C. a change of state. It can be a physical or a chemical state of change.

Answer 2

C. a change of state. 

Signs of a chemical reaction include;
Change of color
formation of gas
change of temperature
Precipitate formation
Energy production.