18.-Escriba el símbolo químico de : a) Sodio
g) Bario
b) Magnesio
h) Bismuto
i) Vanadio
c)) Neón
d) Estroncio
e) Yodo
j) Cobalto
k) Manganeso
1) Litio
f) Polonio
18

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?