We subtract the enthalpies of the reactants from that of the products:
Since this is < 0, this is an exothermic reaction.
Im sorry about my answer a while ago.
answer: it will not be half empty ever. because any gas take all the space of the tank. molecules are everywhere they take so much space.
Oxidation number of an atom is the charge that atom would have if the compound is composed of ions. In neutral substances that contains atoms of one element the oxidation number of an atom is zero. Thus atoms in O2, Ni2, and aluminium all have oxidation number of zero.
In this case, Ni2, the oxidation number of Ni atom is zero,
for NiO4-, assuming oxidation number of Ni is x
(x ×1) + (-2 × 4) = -1
x = + 7
Therefore, the oxidation number goes from 0 to +7
