When one atom of sodium (na) combines with one atom of fluorine (f), they form the compound sodium fluoride (naf). which of the following best describes the arrangement of valence electrons in a bond between na and f? the valence electrons are shared equally between na and f. the valence electrons spend more time around the atom of na. the valence electrons spend more time around the atom of f. the valence electrons are given up by the na and gained by the f.

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.

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