1. Al2O3 Al= ; O= Total # atoms= 2. Ca(OH)2 Ca= ; O= ; H= ___ Total # atoms=

3. Cu(NO3)2 Cu= ___; N= ___; O= ___ Total # atoms=

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.

answer carbon and three oxygen atoms;