Energy is always conserved. It cannot be created or destroyed. It can, however, be transferred between objects or systems, from one form to another. Which of the following is true of the relationship between kinetic and potential energy?
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When a system loses kinetic energy, it loses potential energy.
o
As kinetic energy decreases, potential energy decreases.
When a system gains kinetic energy, it loses potential energy.
As kinetic energy increases, potential energy increases.

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.

let that person have a turn to speak : )