Now, what we know is that the reaction would be exothermic. This knowledge is extractable in two ways. We know quite well that heat is released to the environment or surroundings and also the value of the enthalpy is negative. Thus we conclude that the reaction is exothermic.
Now, since heat is released to the environment, there is the need for an apparatus that would cool down the increased surrounding temperature. Hence, we can conclude that what we need actually is to provide cooling for the reaction mixture
Particles in a solid have fixed locations in a volume that does not change. Solids have a definite volume and shape because particles in a solid vibrate around fixed locations.
