Respuesta :
Hello, I see you need help and I am here to do just that I believe it is C the release of heat Energy hope this helps!
Answer: C) release of heat energy
Explanation: A chemical change is a change which is accompanied by a change in chemical composition of the atoms.
Chemical changes are accompanied by:
a) Change in color
b) Absorption or release of heat
c) formation of precipitates
d) production of gas.
Here no change in color is there, but is given that the tube gets hot, that means the energy has been released.