Respuesta :
Answer is:
Both resulted in gas formation.
Both resulted in temperature change.
One involved chemical change while the other involved physical change.
1) Balanced chemical reaction of magnesium and hydrochloric acid:
Mg + 2HCl → MgCl₂ + H₂(g).
Hydrogen(H₂) is a gas. This is exothermic reaction (energy is released). This is chemical change, new substances are formed.
2) Boiling water is physical change, no new substances are formed. This is endothermic reaction, heat is added. Steam is gas.