Atotal of 5 mol iron oxide has a mass of (798.5g)

Yes , 5 mole of Iron Oxide has mass of  798.5 g

Explanation:

Formula of iron oxide:

Atomic mass of Fe = 55.84 amu

Atomic mass of O = 15.99 amu

Molar mass of Fe2O3 = 2(atomic mass of Fe) + 3(atomic mass of O)

= 2(55.84) + 3(15.99)

=111.68 + 47.97

= 159.69 g/mol

Molar mass always equal to 1 mole of the substance.

1 mole = 159.69 g

5 mole =

= 798.45 g

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.